external_doc doesn't work with crates.io yet :(

# Changes

## Client is now a trait
And `Channel<Req, Resp>` implements `Client<Req, Resp>`. Previously, `Client<Req, Resp>` was a thin wrapper around `Channel<Req, Resp>`.

This was changed to allow for mapping the request and response types. For example, you can take a `channel: Channel<Req, Resp>` and do:

```rust
channel
    .with_request(|req: Req2| -> Req { ... })
    .map_response(|resp: Resp| -> Resp2 { ... })
```

...which returns a type that implements `Client<Req2, Resp2>`.

### Why would you want to map request and response types?

The main benefit of this is that it enables creating different client types backed by the same channel. For example, you could run multiple clients multiplexing requests over a single `TcpStream`. I have a demo in `tarpc/examples/service_registry.rs` showing how you might do this with a bincode transport. I am considering factoring out the service registry portion of that to an actual library, because it's doing pretty cool stuff. For this PR, though, it'll just be part of the example.

## Client::new is now client::new

This is pretty minor, but necessary because async fns can't currently exist on traits. I changed `Server::new` to match this as well.

## Macro-generated Clients are generic over the backing Client.

This is a natural consequence of the above change. However, it is transparent to the user by keeping `Channel<Req, Resp>` as the default type for the `<C: Client>` type parameter. `new_stub` returns `Client<Channel<Req, Resp>>`, and other clients can be created via the `From` trait.

## example-service/ now has two binaries, one for client and one for server.

This serves as a "realistic" example of how one might set up a service. The other examples all run the client and server in the same binary, which isn't realistic in distributed systems use cases.

## `service!` trait fns take self by value.

Services are already cloned per request, so this just passes on that flexibility to the trait implementers.

# Open Questions

In the service registry example, multiple services are running on a single port, and thus multiple clients are sending requests over a single `TcpStream`. This has implications for throttling: [`max_in_flight_requests_per_connection`](https://github.com/google/tarpc/blob/master/rpc/src/server/mod.rs#L57-L60) will set a maximum for the sum of requests for all clients sharing a single connection. I think this is reasonable behavior, but users may expect this setting to act like `max_in_flight_requests_per_client`.

Fixes #103 #153 #205

.travis.yml

@@ -1,34 +1,13 @@
 language: rust
-sudo: false
-
 rust:
     - nightly
+sudo: false
+cache: cargo
 
 os:
+    - osx
     - linux
 
-addons:
-  apt:
-    packages:
-    - libcurl4-openssl-dev
-    - libelf-dev
-    - libdw-dev
-
-before_script:
-- |
-    pip install 'travis-cargo<0.2' --user &&
-    export PATH=$HOME/.local/bin:$PATH
-
 script:
-- |
-    travis-cargo build -- --features tls && travis-cargo test -- --features tls && travis-cargo bench -- --features tls &&
-    rustdoc --test README.md -L target/debug/deps -L target/debug &&
-    travis-cargo build && travis-cargo test && travis-cargo bench
-
-after_success:
-- travis-cargo coveralls --no-sudo
-
-env:
-  global:
-    # override the default `--features unstable` used for the nightly branch
-    - TRAVIS_CARGO_NIGHTLY_FEATURE=""
+  - cargo test --all-targets --all-features
+  - cargo test --doc --all-features

Cargo.toml

@@ -1,56 +1,10 @@
-[package]
-name = "tarpc"
-version = "0.12.0"
-authors = ["Adam Wright <adam.austin.wright@gmail.com>", "Tim Kuehn <timothy.j.kuehn@gmail.com>"]
-license = "MIT"
-documentation = "https://docs.rs/tarpc"
-homepage = "https://github.com/google/tarpc"
-repository = "https://github.com/google/tarpc"
-keywords = ["rpc", "network", "server", "api", "tls"]
-categories = ["asynchronous", "network-programming"]
-readme = "README.md"
-description = "An RPC framework for Rust with a focus on ease of use."
-
-[badges]
-travis-ci = { repository = "google/tarpc" }
-
-[dependencies]
-bincode = "1.0"
-byteorder = "1.0"
-bytes = "0.4"
-cfg-if = "0.1.0"
-futures = "0.1.11"
-lazy_static = "1.0"
-log = "0.4"
-net2 = "0.2"
-num_cpus = "1.0"
-serde = "1.0"
-serde_derive = "1.0"
-tarpc-plugins = { path = "src/plugins", version = "0.4.0" }
-thread-pool = "0.1.1"
-tokio-codec = "0.1"
-tokio-core = "0.1.6"
-tokio-io = "0.1"
-tokio-proto = "0.1.1"
-tokio-service = "0.1"
-
-# Optional dependencies
-native-tls = { version = "0.1", optional = true }
-tokio-tls = { version = "0.1", optional = true }
-
-[dev-dependencies]
-chrono = "0.4"
-env_logger = "0.5"
-futures-cpupool = "0.1"
-clap = "2.0"
-serde_bytes = "0.10"
-
-[target.'cfg(target_os = "macos")'.dev-dependencies]
-security-framework = "0.2"
-
-[features]
-default = []
-tls = ["tokio-tls", "native-tls"]
-unstable = ["serde/unstable"]
-
 [workspace]
+
+members = [
+    "example-service",
+    "rpc",
+    "trace",
+    "bincode-transport",
+    "tarpc",
+    "plugins",
+]

README.md

@@ -31,281 +31,107 @@ works with the community-backed library serde: any serde-serializable type can b
 arguments to tarpc fns.
 
 ## Usage
-**NB**: *this example is for master. Are you looking for other
-[versions](https://docs.rs/tarpc)?*
-
 Add to your `Cargo.toml` dependencies:
 
 ```toml
-tarpc = "0.12.0"
-tarpc-plugins = "0.4.0"
-```
-
-## Example: Sync
-
-tarpc has two APIs: `sync` for blocking code and `future` for asynchronous
-code. Here's how to use the sync api.
-
-```rust
-#![feature(plugin, use_extern_macros, proc_macro_path_invoc)]
-#![plugin(tarpc_plugins)]
-
-#[macro_use]
-extern crate tarpc;
-
-use std::sync::mpsc;
-use std::thread;
-use tarpc::sync::{client, server};
-use tarpc::sync::client::ClientExt;
-use tarpc::util::{FirstSocketAddr, Never};
-
-service! {
-    rpc hello(name: String) -> String;
-}
-
-#[derive(Clone)]
-struct HelloServer;
-
-impl SyncService for HelloServer {
-    fn hello(&self, name: String) -> Result<String, Never> {
-        Ok(format!("Hello, {}!", name))
-    }
-}
-
-fn main() {
-    let (tx, rx) = mpsc::channel();
-    thread::spawn(move || {
-        let mut handle = HelloServer.listen("localhost:0", server::Options::default())
-            .unwrap();
-        tx.send(handle.addr()).unwrap();
-        handle.run();
-    });
-    let client = SyncClient::connect(rx.recv().unwrap(), client::Options::default()).unwrap();
-    println!("{}", client.hello("Mom".to_string()).unwrap());
-}
+tarpc = "0.14.0"
 ```
 
 The `service!` macro expands to a collection of items that form an
 rpc service. In the above example, the macro is called within the
-`hello_service` module. This module will contain `SyncClient`, `AsyncClient`,
-and `FutureClient` types, and `SyncService` and `AsyncService` traits.  There is
-also a `ServiceExt` trait that provides starter `fn`s for services, with an
-umbrella impl for all services.  These generated types make it easy and
-ergonomic to write servers without dealing with sockets or serialization
+`hello_service` module. This module will contain a `Client` stub and `Service` trait.  There is
+These generated types make it easy and ergonomic to write servers without dealing with serialization
 directly. Simply implement one of the generated traits, and you're off to the
-races! See the `tarpc_examples` package for more examples.
+races!
 
-## Example: Futures
+## Example
 
-Here's the same service, implemented using futures.
+Here's a small service.
 
 ```rust
-#![feature(plugin, use_extern_macros, proc_macro_path_invoc)]
-#![plugin(tarpc_plugins)]
+#![feature(futures_api, pin, arbitrary_self_types, await_macro, async_await, proc_macro_hygiene)]
 
-extern crate futures;
-#[macro_use]
-extern crate tarpc;
-extern crate tokio_core;
 
-use futures::Future;
-use tarpc::future::{client, server};
-use tarpc::future::client::ClientExt;
-use tarpc::util::{FirstSocketAddr, Never};
-use tokio_core::reactor;
+use futures::{
+    compat::TokioDefaultSpawner,
+    future::{self, Ready},
+    prelude::*,
+};
+use tarpc::{
+    client, context,
+    server::{self, Handler},
+};
+use std::io;
 
-service! {
+// This is the service definition. It looks a lot like a trait definition.
+// It defines one RPC, hello, which takes one arg, name, and returns a String.
+tarpc::service! {
+    /// Returns a greeting for name.
     rpc hello(name: String) -> String;
 }
 
+// This is the type that implements the generated Service trait. It is the business logic
+// and is used to start the server.
 #[derive(Clone)]
 struct HelloServer;
 
-impl FutureService for HelloServer {
-    type HelloFut = Result<String, Never>;
+impl Service for HelloServer {
+    // Each defined rpc generates two items in the trait, a fn that serves the RPC, and
+    // an associated type representing the future output by the fn.
 
-    fn hello(&self, name: String) -> Self::HelloFut {
-        Ok(format!("Hello, {}!", name))
+    type HelloFut = Ready<String>;
+
+    fn hello(self, _: context::Context, name: String) -> Self::HelloFut {
+        future::ready(format!("Hello, {}!", name))
     }
 }
 
-fn main() {
-    let mut reactor = reactor::Core::new().unwrap();
-    let (handle, server) = HelloServer.listen("localhost:10000".first_socket_addr(),
-                                  &reactor.handle(),
-                                  server::Options::default())
-                          .unwrap();
-    reactor.handle().spawn(server);
-    let options = client::Options::default().handle(reactor.handle());
-    reactor.run(FutureClient::connect(handle.addr(), options)
-            .map_err(tarpc::Error::from)
-            .and_then(|client| client.hello("Mom".to_string()))
-            .map(|resp| println!("{}", resp)))
-        .unwrap();
-}
-```
+async fn run() -> io::Result<()> {
+    // bincode_transport is provided by the associated crate bincode-transport. It makes it easy
+    // to start up a serde-powered bincode serialization strategy over TCP.
+    let transport = bincode_transport::listen(&"0.0.0.0:0".parse().unwrap())?;
+    let addr = transport.local_addr();
 
-## Example: Futures + TLS
+    // The server is configured with the defaults.
+    let server = server::new(server::Config::default())
+        // Server can listen on any type that implements the Transport trait.
+        .incoming(transport)
+        // Close the stream after the client connects
+        .take(1)
+        // serve is generated by the service! macro. It takes as input any type implementing
+        // the generated Service trait.
+        .respond_with(serve(HelloServer));
 
-By default, tarpc internally uses a [`TcpStream`] for communication between your clients and
-servers. However, TCP by itself has no encryption. As a result, your communication will be sent in
-the clear. If you want your RPC communications to be encrypted, you can choose to use [TLS]. TLS
-operates as an encryption layer on top of TCP. When using TLS, your communication will occur over a
-[`TlsStream<TcpStream>`]. You can add the ability to make TLS clients and servers by adding `tarpc`
-with the `tls` feature flag enabled.
+    tokio_executor::spawn(server.unit_error().boxed().compat());
 
-When using TLS, some additional information is required. You will need to make [`TlsAcceptor`] and
-`client::tls::Context` structs; `client::tls::Context` requires a [`TlsConnector`]. The
-[`TlsAcceptor`] and [`TlsConnector`] types are defined in the [native-tls]. tarpc re-exports
-external TLS-related types in its `native_tls` module (`tarpc::native_tls`).
+    let transport = await!(bincode_transport::connect(&addr))?;
 
-[TLS]: https://en.wikipedia.org/wiki/Transport_Layer_Security
-[`TcpStream`]: https://docs.rs/tokio-core/0.1/tokio_core/net/struct.TcpStream.html
-[`TlsStream<TcpStream>`]: https://docs.rs/native-tls/0.1/native_tls/struct.TlsStream.html
-[`TlsAcceptor`]: https://docs.rs/native-tls/0.1/native_tls/struct.TlsAcceptor.html
-[`TlsConnector`]: https://docs.rs/native-tls/0.1/native_tls/struct.TlsConnector.html
-[native-tls]: https://github.com/sfackler/rust-native-tls
+    // new_stub is generated by the service! macro. Like Server, it takes a config and any
+    // Transport as input, and returns a Client, also generated by the macro.
+    // by the service mcro.
+    let mut client = await!(new_stub(client::Config::default(), transport))?;
 
-Both TLS streams and TCP streams are supported in the same binary when the `tls` feature is enabled.
-However, if you are working with both stream types, ensure that you use the TLS clients with TLS
-servers and TCP clients with TCP servers.
+    // The client has an RPC method for each RPC defined in service!. It takes the same args
+    // as defined, with the addition of a Context, which is always the first arg. The Context
+    // specifies a deadline and trace information which can be helpful in debugging requests.
+    let hello = await!(client.hello(context::current(), "Stim".to_string()))?;
 
-```rust,no_run
-#![feature(plugin, use_extern_macros, proc_macro_path_invoc)]
-#![plugin(tarpc_plugins)]
+    println!("{}", hello);
 
-extern crate futures;
-#[macro_use]
-extern crate tarpc;
-extern crate tokio_core;
-
-use futures::Future;
-use tarpc::future::{client, server};
-use tarpc::future::client::ClientExt;
-use tarpc::tls;
-use tarpc::util::{FirstSocketAddr, Never};
-use tokio_core::reactor;
-use tarpc::native_tls::{Pkcs12, TlsAcceptor};
-
-service! {
-    rpc hello(name: String) -> String;
-}
-
-#[derive(Clone)]
-struct HelloServer;
-
-impl FutureService for HelloServer {
-    type HelloFut = Result<String, Never>;
-
-    fn hello(&self, name: String) -> Self::HelloFut {
-        Ok(format!("Hello, {}!", name))
-    }
-}
-
-fn get_acceptor() -> TlsAcceptor {
-    let buf = include_bytes!("test/identity.p12");
-    let pkcs12 = Pkcs12::from_der(buf, "password").unwrap();
-    TlsAcceptor::builder(pkcs12).unwrap().build().unwrap()
+    Ok(())
 }
 
 fn main() {
-    let mut reactor = reactor::Core::new().unwrap();
-    let acceptor = get_acceptor();
-    let (handle, server) = HelloServer.listen("localhost:10000".first_socket_addr(),
-                                            &reactor.handle(),
-                                            server::Options::default().tls(acceptor)).unwrap();
-    reactor.handle().spawn(server);
-    let options = client::Options::default()
-                                   .handle(reactor.handle())
-                                   .tls(tls::client::Context::new("foobar.com").unwrap());
-    reactor.run(FutureClient::connect(handle.addr(), options)
-            .map_err(tarpc::Error::from)
-            .and_then(|client| client.hello("Mom".to_string()))
-            .map(|resp| println!("{}", resp)))
-        .unwrap();
+    tarpc::init(TokioDefaultSpawner);
+    tokio::run(run()
+            .map_err(|e| eprintln!("Oh no: {}", e))
+            .boxed()
+            .compat(),
+    );
 }
 ```
 
-## Tips
-
-### Sync vs Futures
-
-A single `service!` invocation generates code for both synchronous and future-based applications.
-It's up to the user whether they want to implement the sync API or the futures API. The sync API has
-the simplest programming model, at the cost of some overhead - each RPC is handled in its own
-thread. The futures API is based on tokio and can run on any tokio-compatible executor. This mean a
-service that implements the futures API for a tarpc service can run on a single thread, avoiding
-context switches and the memory overhead of having a thread per RPC.
-
-### Errors
-
-All generated tarpc RPC methods return either `tarpc::Result<T, E>` or something like `Future<T,
-E>`. The error type defaults to `tarpc::util::Never` (a wrapper for `!` which implements
-`std::error::Error`) if no error type is explicitly specified in the `service!` macro invocation. An
-error type can be specified like so:
-
-```rust,ignore
-use tarpc::util::Message;
-
-service! {
-    rpc hello(name: String) -> String | Message
-}
-```
-
-`tarpc::util::Message` is just a wrapper around string that implements `std::error::Error` provided
-for service implementations that don't require complex error handling. The pipe is used as syntax
-for specifying the error type in a way that's agnostic of whether the service implementation is
-synchronous or future-based. Note that in the simpler examples in the readme, no pipe is used, and
-the macro automatically chooses `tarpc::util::Never` as the error type.
-
-The above declaration would produce the following synchronous service trait:
-
-```rust,ignore
-trait SyncService {
-    fn hello(&self, name: String) -> Result<String, Message>;
-}
-```
-
-and the following future-based trait:
-
-```rust,ignore
-trait FutureService {
-    type HelloFut: IntoFuture<String, Message>;
-
-    fn hello(&mut self, name: String) -> Self::HelloFut;
-}
-```
-
-## Documentation
+## Service Documentation
 
 Use `cargo doc` as you normally would to see the documentation created for all
 items expanded by a `service!` invocation.
-
-## Additional Features
-
-- Concurrent requests from a single client.
-- Compatible with tokio services.
-- Run any number of clients and services on a single event loop.
-- Any type that `impl`s `serde`'s `Serialize` and `Deserialize` can be used in
-  rpc signatures.
-- Attributes can be specified on rpc methods. These will be included on both the
-  services' trait methods as well as on the clients' stub methods.
-
-## Gaps/Potential Improvements (not necessarily actively being worked on)
-
-- Configurable server rate limiting.
-- Automatic client retries with exponential backoff when server is busy.
-- Load balancing
-- Service discovery
-- Automatically reconnect on the client side when the connection cuts out.
-- Support generic serialization protocols.
-
-## Contributing
-
-To contribute to tarpc, please see [CONTRIBUTING](CONTRIBUTING.md).
-
-## License
-
-tarpc is distributed under the terms of the MIT license.
-
-See [LICENSE](LICENSE) for details.

RELEASES.md

@@ -1,21 +1,52 @@
+## 0.13.0 (2018-10-16)
+
+### Breaking Changes 
+
+Version 0.13 marks a significant departure from previous versions of tarpc. The
+API has changed significantly. The tokio-proto crate has been torn out and
+replaced with a homegrown rpc framework. Additionally, the crate has been
+modularized, so that the tarpc crate itself contains only the macro code.
+
+### New Crates
+
+- crate rpc contains the core client/server request-response framework, as well as a transport trait.
+- crate bincode-transport implements a transport that works almost exactly as tarpc works today (not to say it's wire-compatible).
+- crate trace has some foundational types for tracing. This isn't really fleshed out yet, but it's useful for in-process log tracing, at least.
+
+All crates are now at the top level. e.g. tarpc-plugins is now tarpc/plugins rather than tarpc/src/plugins. tarpc itself is now a *very* small code surface, as most functionality has been moved into the other more granular crates.
+
+### New Features
+- deadlines: all requests specify a deadline, and a server will stop processing a response when past its deadline.
+- client cancellation propagation: when a client drops a request, the client sends a message to the server informing it to cancel its response. This means cancellations can propagate across multiple server hops.
+- trace context stuff as mentioned above
+- more server configuration for total connection limits, per-connection request limits, etc.
+
+### Removals
+- no more shutdown handle.  I left it out for now because of time and not being sure what the right solution is.
+- all async now, no blocking stub or server interface. This helps with maintainability, and async/await makes async code much more usable. The service trait is thusly renamed Service, and the client is renamed Client.
+- no built-in transport. Tarpc is now transport agnostic (see bincode-transport for transitioning existing uses).
+- going along with the previous bullet, no preferred transport means no TLS support at this time. We could make a tls transport or make bincode-transport compatible with TLS.
+- a lot of examples were removed because I couldn't keep up with maintaining all of them. Hopefully the ones I kept are still illustrative.
+- no more plugins!
+
 ## 0.10.0 (2018-04-08)
 
-## Breaking Changes
+### Breaking Changes
 Fixed rustc breakage in tarpc-plugins. These changes require a recent version of rustc.
 
 ## 0.10.0 (2018-03-26)
 
-## Breaking Changes
+### Breaking Changes
 Updates bincode to version 1.0.
 
 ## 0.9.0 (2017-09-17)
 
-## Breaking Changes
+### Breaking Changes
 Updates tarpc to use tarpc-plugins 0.2.
 
 ## 0.8.0 (2017-05-05)
 
-## Breaking Changes
+### Breaking Changes
 This release updates tarpc to use serde 1.0.
 As such, users must also update to use serde 1.0.
 The serde 1.0 [release notes](https://github.com/serde-rs/serde/releases/tag/v1.0.0)
@@ -28,7 +59,7 @@ clients. No breaking changes.
 
 ## 0.7.2 (2017-04-22)
 
-## Breaking Changes
+### Breaking Changes
 This release updates tarpc-plugins to work with rustc master. Thus, older
 versions of rustc are no longer supported. We chose a minor version bump
 because it is still source-compatible with existing code using tarpc.
@@ -39,7 +70,7 @@ This release was purely doc fixes. No breaking changes.
 
 ## 0.7 (2017-03-31)
 
-## Breaking Changes
+### Breaking Changes
 This release is a complete overhaul to build tarpc on top of the tokio stack.
 It's safe to assume that everything broke with this release.
 

benches/latency.rs

@@ -1,58 +0,0 @@
-// Copyright 2016 Google Inc. All Rights Reserved.
-//
-// Licensed under the MIT License, <LICENSE or http://opensource.org/licenses/MIT>.
-// This file may not be copied, modified, or distributed except according to those terms.
-
-#![feature(plugin, test, use_extern_macros, proc_macro_path_invoc)]
-#![plugin(tarpc_plugins)]
-
-#[macro_use]
-extern crate tarpc;
-#[cfg(test)]
-extern crate test;
-extern crate env_logger;
-extern crate futures;
-extern crate tokio_core;
-
-use tarpc::future::{client, server};
-use tarpc::future::client::ClientExt;
-use tarpc::util::{FirstSocketAddr, Never};
-#[cfg(test)]
-use test::Bencher;
-use tokio_core::reactor;
-
-service! {
-    rpc ack();
-}
-
-#[derive(Clone)]
-struct Server;
-
-impl FutureService for Server {
-    type AckFut = futures::Finished<(), Never>;
-    fn ack(&self) -> Self::AckFut {
-        futures::finished(())
-    }
-}
-
-#[cfg(test)]
-#[bench]
-fn latency(bencher: &mut Bencher) {
-    let _ = env_logger::try_init();
-    let mut reactor = reactor::Core::new().unwrap();
-    let (handle, server) = Server
-        .listen(
-            "localhost:0".first_socket_addr(),
-            &reactor.handle(),
-            server::Options::default(),
-        )
-        .unwrap();
-    reactor.handle().spawn(server);
-    let client = FutureClient::connect(
-        handle.addr(),
-        client::Options::default().handle(reactor.handle()),
-    );
-    let client = reactor.run(client).unwrap();
-
-    bencher.iter(|| reactor.run(client.ack()).unwrap());
-}

bincode-transport/Cargo.toml

@@ -0,0 +1,40 @@
+cargo-features = ["rename-dependency"]
+
+[package]
+name = "tarpc-bincode-transport"
+version = "0.3.0"
+authors = ["Tim Kuehn <tikue@google.com>"]
+edition = '2018'
+license = "MIT"
+documentation = "https://docs.rs/tarpc-bincode-transport"
+homepage = "https://github.com/google/tarpc"
+repository = "https://github.com/google/tarpc"
+keywords = ["rpc", "network", "bincode", "serde", "tarpc"]
+categories = ["asynchronous", "network-programming"]
+readme = "../README.md"
+description = "A bincode-based transport for tarpc services."
+
+[dependencies]
+bincode = { version = "1.0", features = ["i128"] }
+futures_legacy = { version = "0.1", package = "futures" }
+pin-utils = "0.1.0-alpha.3"
+rpc = { package = "tarpc-lib", version = "0.2", path = "../rpc", features = ["serde1"] }
+serde = "1.0"
+tokio-io = "0.1"
+async-bincode = "0.4"
+tokio-tcp = "0.1"
+
+[target.'cfg(not(test))'.dependencies]
+futures-preview = { version = "0.3.0-alpha.9", features = ["compat"] }
+
+[dev-dependencies]
+futures-preview = { version = "0.3.0-alpha.9", features = ["compat", "tokio-compat"] }
+env_logger = "0.5"
+humantime = "1.0"
+log = "0.4"
+rand = "0.5"
+tokio = "0.1"
+tokio-executor = "0.1"
+tokio-reactor = "0.1"
+tokio-serde = "0.2"
+tokio-timer = "0.2"

bincode-transport/rustfmt.toml

@@ -0,0 +1 @@
+edition = "2018"

bincode-transport/src/compat.rs

@@ -0,0 +1,150 @@
+use futures::{compat::Stream01CompatExt, prelude::*, ready};
+use futures_legacy::{
+    executor::{
+        self as executor01, Notify as Notify01, NotifyHandle as NotifyHandle01,
+        UnsafeNotify as UnsafeNotify01,
+    },
+    Async as Async01, AsyncSink as AsyncSink01, Sink as Sink01, Stream as Stream01,
+};
+use std::{
+    pin::Pin,
+    task::{self, LocalWaker, Poll},
+};
+
+/// A shim to convert a 0.1 Sink + Stream to a 0.3 Sink + Stream.
+#[derive(Debug)]
+pub struct Compat<S, SinkItem> {
+    staged_item: Option<SinkItem>,
+    inner: S,
+}
+
+impl<S, SinkItem> Compat<S, SinkItem> {
+    /// Returns a new Compat.
+    pub fn new(inner: S) -> Self {
+        Compat {
+            inner,
+            staged_item: None,
+        }
+    }
+
+    /// Unwraps Compat, returning the inner value.
+    pub fn into_inner(self) -> S {
+        self.inner
+    }
+
+    /// Returns a reference to the value wrapped by Compat.
+    pub fn get_ref(&self) -> &S {
+        &self.inner
+    }
+}
+
+impl<S, SinkItem> Stream for Compat<S, SinkItem>
+where
+    S: Stream01,
+{
+    type Item = Result<S::Item, S::Error>;
+
+    fn poll_next(self: Pin<&mut Self>, waker: &LocalWaker) -> Poll<Option<Self::Item>> {
+        unsafe {
+            let inner = &mut Pin::get_mut_unchecked(self).inner;
+            let mut compat = inner.compat();
+            let compat = Pin::new_unchecked(&mut compat);
+            match ready!(compat.poll_next(waker)) {
+                None => Poll::Ready(None),
+                Some(Ok(next)) => Poll::Ready(Some(Ok(next))),
+                Some(Err(e)) => Poll::Ready(Some(Err(e))),
+            }
+        }
+    }
+}
+
+impl<S, SinkItem> Sink for Compat<S, SinkItem>
+where
+    S: Sink01<SinkItem = SinkItem>,
+{
+    type SinkItem = SinkItem;
+    type SinkError = S::SinkError;
+
+    fn start_send(self: Pin<&mut Self>, item: SinkItem) -> Result<(), S::SinkError> {
+        let me = unsafe { Pin::get_mut_unchecked(self) };
+        assert!(me.staged_item.is_none());
+        me.staged_item = Some(item);
+        Ok(())
+    }
+
+    fn poll_ready(self: Pin<&mut Self>, waker: &LocalWaker) -> Poll<Result<(), S::SinkError>> {
+        let notify = &WakerToHandle(waker);
+
+        executor01::with_notify(notify, 0, move || {
+            let me = unsafe { Pin::get_mut_unchecked(self) };
+            match me.staged_item.take() {
+                Some(staged_item) => match me.inner.start_send(staged_item) {
+                    Ok(AsyncSink01::Ready) => Poll::Ready(Ok(())),
+                    Ok(AsyncSink01::NotReady(item)) => {
+                        me.staged_item = Some(item);
+                        Poll::Pending
+                    }
+                    Err(e) => Poll::Ready(Err(e)),
+                },
+                None => Poll::Ready(Ok(())),
+            }
+        })
+    }
+
+    fn poll_flush(self: Pin<&mut Self>, waker: &LocalWaker) -> Poll<Result<(), S::SinkError>> {
+        let notify = &WakerToHandle(waker);
+
+        executor01::with_notify(notify, 0, move || {
+            let me = unsafe { Pin::get_mut_unchecked(self) };
+            match me.inner.poll_complete() {
+                Ok(Async01::Ready(())) => Poll::Ready(Ok(())),
+                Ok(Async01::NotReady) => Poll::Pending,
+                Err(e) => Poll::Ready(Err(e)),
+            }
+        })
+    }
+
+    fn poll_close(self: Pin<&mut Self>, waker: &LocalWaker) -> Poll<Result<(), S::SinkError>> {
+        let notify = &WakerToHandle(waker);
+
+        executor01::with_notify(notify, 0, move || {
+            let me = unsafe { Pin::get_mut_unchecked(self) };
+            match me.inner.close() {
+                Ok(Async01::Ready(())) => Poll::Ready(Ok(())),
+                Ok(Async01::NotReady) => Poll::Pending,
+                Err(e) => Poll::Ready(Err(e)),
+            }
+        })
+    }
+}
+
+#[derive(Clone, Debug)]
+struct WakerToHandle<'a>(&'a LocalWaker);
+
+#[derive(Debug)]
+struct NotifyWaker(task::Waker);
+
+impl Notify01 for NotifyWaker {
+    fn notify(&self, _: usize) {
+        self.0.wake();
+    }
+}
+
+unsafe impl UnsafeNotify01 for NotifyWaker {
+    unsafe fn clone_raw(&self) -> NotifyHandle01 {
+        let ptr = Box::new(NotifyWaker(self.0.clone()));
+
+        NotifyHandle01::new(Box::into_raw(ptr))
+    }
+
+    unsafe fn drop_raw(&self) {
+        let ptr: *const dyn UnsafeNotify01 = self;
+        drop(Box::from_raw(ptr as *mut dyn UnsafeNotify01));
+    }
+}
+
+impl<'a> From<WakerToHandle<'a>> for NotifyHandle01 {
+    fn from(handle: WakerToHandle<'a>) -> NotifyHandle01 {
+        unsafe { NotifyWaker(handle.0.clone().into_waker()).clone_raw() }
+    }
+}

bincode-transport/src/lib.rs

@@ -0,0 +1,202 @@
+// Copyright 2018 Google LLC
+//
+// Use of this source code is governed by an MIT-style
+// license that can be found in the LICENSE file or at
+// https://opensource.org/licenses/MIT.
+
+//! A TCP [`Transport`] that serializes as bincode.
+
+#![feature(
+    futures_api,
+    pin,
+    arbitrary_self_types,
+    await_macro,
+    async_await
+)]
+#![deny(missing_docs, missing_debug_implementations)]
+
+use self::compat::Compat;
+use async_bincode::{AsyncBincodeStream, AsyncDestination};
+use futures::{
+    compat::{Compat01As03, Future01CompatExt, Stream01CompatExt},
+    prelude::*,
+    ready,
+};
+use pin_utils::unsafe_pinned;
+use serde::{Deserialize, Serialize};
+use std::{
+    error::Error,
+    io,
+    marker::PhantomData,
+    net::SocketAddr,
+    pin::Pin,
+    task::{LocalWaker, Poll},
+};
+use tokio_io::{AsyncRead, AsyncWrite};
+use tokio_tcp::{TcpListener, TcpStream};
+
+mod compat;
+
+/// A transport that serializes to, and deserializes from, a [`TcpStream`].
+#[derive(Debug)]
+pub struct Transport<S, Item, SinkItem> {
+    inner: Compat<AsyncBincodeStream<S, Item, SinkItem, AsyncDestination>, SinkItem>,
+}
+
+impl<S, Item, SinkItem> Transport<S, Item, SinkItem> {
+    /// Returns the transport underlying the bincode transport.
+    pub fn into_inner(self) -> S {
+        self.inner.into_inner().into_inner()
+    }
+}
+
+impl<S, Item, SinkItem> Transport<S, Item, SinkItem> {
+    unsafe_pinned!(
+        inner: Compat<AsyncBincodeStream<S, Item, SinkItem, AsyncDestination>, SinkItem>
+    );
+}
+
+impl<S, Item, SinkItem> Stream for Transport<S, Item, SinkItem>
+where
+    S: AsyncRead,
+    Item: for<'a> Deserialize<'a>,
+{
+    type Item = io::Result<Item>;
+
+    fn poll_next(mut self: Pin<&mut Self>, waker: &LocalWaker) -> Poll<Option<io::Result<Item>>> {
+        match self.inner().poll_next(waker) {
+            Poll::Pending => Poll::Pending,
+            Poll::Ready(None) => Poll::Ready(None),
+            Poll::Ready(Some(Ok(next))) => Poll::Ready(Some(Ok(next))),
+            Poll::Ready(Some(Err(e))) => {
+                Poll::Ready(Some(Err(io::Error::new(io::ErrorKind::Other, e))))
+            }
+        }
+    }
+}
+
+impl<S, Item, SinkItem> Sink for Transport<S, Item, SinkItem>
+where
+    S: AsyncWrite,
+    SinkItem: Serialize,
+{
+    type SinkItem = SinkItem;
+    type SinkError = io::Error;
+
+    fn start_send(mut self: Pin<&mut Self>, item: SinkItem) -> io::Result<()> {
+        self.inner()
+            .start_send(item)
+            .map_err(|e| io::Error::new(io::ErrorKind::Other, e))
+    }
+
+    fn poll_ready(mut self: Pin<&mut Self>, waker: &LocalWaker) -> Poll<io::Result<()>> {
+        convert(self.inner().poll_ready(waker))
+    }
+
+    fn poll_flush(mut self: Pin<&mut Self>, waker: &LocalWaker) -> Poll<io::Result<()>> {
+        convert(self.inner().poll_flush(waker))
+    }
+
+    fn poll_close(mut self: Pin<&mut Self>, waker: &LocalWaker) -> Poll<io::Result<()>> {
+        convert(self.inner().poll_close(waker))
+    }
+}
+
+fn convert<E: Into<Box<Error + Send + Sync>>>(poll: Poll<Result<(), E>>) -> Poll<io::Result<()>> {
+    match poll {
+        Poll::Pending => Poll::Pending,
+        Poll::Ready(Ok(())) => Poll::Ready(Ok(())),
+        Poll::Ready(Err(e)) => Poll::Ready(Err(io::Error::new(io::ErrorKind::Other, e))),
+    }
+}
+
+impl<Item, SinkItem> rpc::Transport for Transport<TcpStream, Item, SinkItem>
+where
+    Item: for<'de> Deserialize<'de>,
+    SinkItem: Serialize,
+{
+    type Item = Item;
+    type SinkItem = SinkItem;
+
+    fn peer_addr(&self) -> io::Result<SocketAddr> {
+        self.inner.get_ref().get_ref().peer_addr()
+    }
+
+    fn local_addr(&self) -> io::Result<SocketAddr> {
+        self.inner.get_ref().get_ref().local_addr()
+    }
+}
+
+/// Returns a new bincode transport that reads from and writes to `io`.
+pub fn new<Item, SinkItem>(io: TcpStream) -> Transport<TcpStream, Item, SinkItem>
+where
+    Item: for<'de> Deserialize<'de>,
+    SinkItem: Serialize,
+{
+    Transport::from(io)
+}
+
+impl<S, Item, SinkItem> From<S> for Transport<S, Item, SinkItem> {
+    fn from(inner: S) -> Self {
+        Transport {
+            inner: Compat::new(AsyncBincodeStream::from(inner).for_async()),
+        }
+    }
+}
+
+/// Connects to `addr`, wrapping the connection in a bincode transport.
+pub async fn connect<Item, SinkItem>(
+    addr: &SocketAddr,
+) -> io::Result<Transport<TcpStream, Item, SinkItem>>
+where
+    Item: for<'de> Deserialize<'de>,
+    SinkItem: Serialize,
+{
+    Ok(new(await!(TcpStream::connect(addr).compat())?))
+}
+
+/// Listens on `addr`, wrapping accepted connections in bincode transports.
+pub fn listen<Item, SinkItem>(addr: &SocketAddr) -> io::Result<Incoming<Item, SinkItem>>
+where
+    Item: for<'de> Deserialize<'de>,
+    SinkItem: Serialize,
+{
+    let listener = TcpListener::bind(addr)?;
+    let local_addr = listener.local_addr()?;
+    let incoming = listener.incoming().compat();
+    Ok(Incoming {
+        incoming,
+        local_addr,
+        ghost: PhantomData,
+    })
+}
+
+/// A [`TcpListener`] that wraps connections in bincode transports.
+#[derive(Debug)]
+pub struct Incoming<Item, SinkItem> {
+    incoming: Compat01As03<tokio_tcp::Incoming>,
+    local_addr: SocketAddr,
+    ghost: PhantomData<(Item, SinkItem)>,
+}
+
+impl<Item, SinkItem> Incoming<Item, SinkItem> {
+    unsafe_pinned!(incoming: Compat01As03<tokio_tcp::Incoming>);
+
+    /// Returns the address being listened on.
+    pub fn local_addr(&self) -> SocketAddr {
+        self.local_addr
+    }
+}
+
+impl<Item, SinkItem> Stream for Incoming<Item, SinkItem>
+where
+    Item: for<'a> Deserialize<'a>,
+    SinkItem: Serialize,
+{
+    type Item = io::Result<Transport<TcpStream, Item, SinkItem>>;
+
+    fn poll_next(mut self: Pin<&mut Self>, waker: &LocalWaker) -> Poll<Option<Self::Item>> {
+        let next = ready!(self.incoming().poll_next(waker)?);
+        Poll::Ready(next.map(|conn| Ok(new(conn))))
+    }
+}

bincode-transport/tests/bench.rs

@@ -0,0 +1,110 @@
+// Copyright 2018 Google LLC
+//
+// Use of this source code is governed by an MIT-style
+// license that can be found in the LICENSE file or at
+// https://opensource.org/licenses/MIT.
+
+//! Tests client/server control flow.
+
+#![feature(
+    test,
+    integer_atomics,
+    futures_api,
+    generators,
+    await_macro,
+    async_await
+)]
+
+extern crate test;
+
+use self::test::stats::Stats;
+use futures::{compat::TokioDefaultSpawner, prelude::*};
+use rpc::{
+    client, context,
+    server::{Handler, Server},
+};
+use std::{
+    io,
+    time::{Duration, Instant},
+};
+
+async fn bench() -> io::Result<()> {
+    let listener = tarpc_bincode_transport::listen(&"0.0.0.0:0".parse().unwrap())?;
+    let addr = listener.local_addr();
+
+    tokio_executor::spawn(
+        Server::<u32, u32>::default()
+            .incoming(listener)
+            .take(1)
+            .respond_with(|_ctx, request| futures::future::ready(Ok(request)))
+            .unit_error()
+            .boxed()
+            .compat(),
+    );
+
+    let conn = await!(tarpc_bincode_transport::connect(&addr))?;
+    let client = &mut await!(client::new::<u32, u32, _>(client::Config::default(), conn))?;
+
+    let total = 10_000usize;
+    let mut successful = 0u32;
+    let mut unsuccessful = 0u32;
+    let mut durations = vec![];
+    for _ in 1..=total {
+        let now = Instant::now();
+        let response = await!(client.call(context::current(), 0u32));
+        let elapsed = now.elapsed();
+
+        match response {
+            Ok(_) => successful += 1,
+            Err(_) => unsuccessful += 1,
+        };
+        durations.push(elapsed);
+    }
+
+    let durations_nanos = durations
+        .iter()
+        .map(|duration| duration.as_secs() as f64 * 1E9 + duration.subsec_nanos() as f64)
+        .collect::<Vec<_>>();
+
+    let (lower, median, upper) = durations_nanos.quartiles();
+
+    println!("Of {} runs:", durations_nanos.len());
+    println!("\tSuccessful: {}", successful);
+    println!("\tUnsuccessful: {}", unsuccessful);
+    println!(
+        "\tMean: {:?}",
+        Duration::from_nanos(durations_nanos.mean() as u64)
+    );
+    println!("\tMedian: {:?}", Duration::from_nanos(median as u64));
+    println!(
+        "\tStd Dev: {:?}",
+        Duration::from_nanos(durations_nanos.std_dev() as u64)
+    );
+    println!(
+        "\tMin: {:?}",
+        Duration::from_nanos(durations_nanos.min() as u64)
+    );
+    println!(
+        "\tMax: {:?}",
+        Duration::from_nanos(durations_nanos.max() as u64)
+    );
+    println!(
+        "\tQuartiles: ({:?}, {:?}, {:?})",
+        Duration::from_nanos(lower as u64),
+        Duration::from_nanos(median as u64),
+        Duration::from_nanos(upper as u64)
+    );
+
+    Ok(())
+}
+
+#[test]
+fn bench_small_packet() -> io::Result<()> {
+    env_logger::init();
+    rpc::init(TokioDefaultSpawner);
+
+    tokio::run(bench().map_err(|e| panic!(e.to_string())).boxed().compat());
+    println!("done");
+
+    Ok(())
+}

bincode-transport/tests/cancel.rs

@@ -0,0 +1,143 @@
+// Copyright 2018 Google LLC
+//
+// Use of this source code is governed by an MIT-style
+// license that can be found in the LICENSE file or at
+// https://opensource.org/licenses/MIT.
+
+//! Tests client/server control flow.
+
+#![feature(generators, await_macro, async_await, futures_api)]
+
+use futures::{
+    compat::{Future01CompatExt, TokioDefaultSpawner},
+    prelude::*,
+    stream,
+};
+use log::{info, trace};
+use rand::distributions::{Distribution, Normal};
+use rpc::{client, context, server::Server};
+use std::{
+    io,
+    time::{Duration, Instant, SystemTime},
+};
+use tokio::timer::Delay;
+
+pub trait AsDuration {
+    /// Delay of 0 if self is in the past
+    fn as_duration(&self) -> Duration;
+}
+
+impl AsDuration for SystemTime {
+    fn as_duration(&self) -> Duration {
+        self.duration_since(SystemTime::now()).unwrap_or_default()
+    }
+}
+
+async fn run() -> io::Result<()> {
+    let listener = tarpc_bincode_transport::listen(&"0.0.0.0:0".parse().unwrap())?;
+    let addr = listener.local_addr();
+    let server = Server::<String, String>::default()
+        .incoming(listener)
+        .take(1)
+        .for_each(async move |channel| {
+            let channel = if let Ok(channel) = channel {
+                channel
+            } else {
+                return;
+            };
+            let client_addr = *channel.client_addr();
+            let handler = channel.respond_with(move |ctx, request| {
+                // Sleep for a time sampled from a normal distribution with:
+                // - mean: 1/2 the deadline.
+                // - std dev: 1/2 the deadline.
+                let deadline: Duration = ctx.deadline.as_duration();
+                let deadline_millis = deadline.as_secs() * 1000 + deadline.subsec_millis() as u64;
+                let distribution =
+                    Normal::new(deadline_millis as f64 / 2., deadline_millis as f64 / 2.);
+                let delay_millis = distribution.sample(&mut rand::thread_rng()).max(0.);
+                let delay = Duration::from_millis(delay_millis as u64);
+
+                trace!(
+                    "[{}/{}] Responding to request in {:?}.",
+                    ctx.trace_id(),
+                    client_addr,
+                    delay,
+                );
+
+                let wait = Delay::new(Instant::now() + delay).compat();
+                async move {
+                    await!(wait).unwrap();
+                    Ok(request)
+                }
+            });
+            tokio_executor::spawn(handler.unit_error().boxed().compat());
+        });
+
+    tokio_executor::spawn(server.unit_error().boxed().compat());
+
+    let conn = await!(tarpc_bincode_transport::connect(&addr))?;
+    let client = await!(client::new::<String, String, _>(
+        client::Config::default(),
+        conn
+    ))?;
+
+    // Proxy service
+    let listener = tarpc_bincode_transport::listen(&"0.0.0.0:0".parse().unwrap())?;
+    let addr = listener.local_addr();
+    let proxy_server = Server::<String, String>::default()
+        .incoming(listener)
+        .take(1)
+        .for_each(move |channel| {
+            let client = client.clone();
+            async move {
+                let channel = if let Ok(channel) = channel {
+                    channel
+                } else {
+                    return;
+                };
+                let client_addr = *channel.client_addr();
+                let handler = channel.respond_with(move |ctx, request| {
+                    trace!("[{}/{}] Proxying request.", ctx.trace_id(), client_addr);
+                    let mut client = client.clone();
+                    async move { await!(client.call(ctx, request)) }
+                });
+                tokio_executor::spawn(handler.unit_error().boxed().compat());
+            }
+        });
+
+    tokio_executor::spawn(proxy_server.unit_error().boxed().compat());
+
+    let mut config = client::Config::default();
+    config.max_in_flight_requests = 10;
+    config.pending_request_buffer = 10;
+
+    let client = await!(client::new::<String, String, _>(
+        config,
+        await!(tarpc_bincode_transport::connect(&addr))?
+    ))?;
+
+    // Make 3 speculative requests, returning only the quickest.
+    let mut clients: Vec<_> = (1..=3u32).map(|_| client.clone()).collect();
+    let mut requests = vec![];
+    for client in &mut clients {
+        let mut ctx = context::current();
+        ctx.deadline = SystemTime::now() + Duration::from_millis(200);
+        let trace_id = *ctx.trace_id();
+        let response = client.call(ctx, "ping".into());
+        requests.push(response.map(move |r| (trace_id, r)));
+    }
+    let (fastest_response, _) = await!(stream::futures_unordered(requests).into_future());
+    let (trace_id, resp) = fastest_response.unwrap();
+    info!("[{}] fastest_response = {:?}", trace_id, resp);
+
+    Ok::<_, io::Error>(())
+}
+
+#[test]
+fn cancel_slower() -> io::Result<()> {
+    env_logger::init();
+    rpc::init(TokioDefaultSpawner);
+
+    tokio::run(run().boxed().map_err(|e| panic!(e)).compat());
+    Ok(())
+}

bincode-transport/tests/pushback.rs

@@ -0,0 +1,119 @@
+// Copyright 2018 Google LLC
+//
+// Use of this source code is governed by an MIT-style
+// license that can be found in the LICENSE file or at
+// https://opensource.org/licenses/MIT.
+
+//! Tests client/server control flow.
+
+#![feature(generators, await_macro, async_await, futures_api)]
+
+use futures::{
+    compat::{Future01CompatExt, TokioDefaultSpawner},
+    prelude::*,
+};
+use log::{error, info, trace};
+use rand::distributions::{Distribution, Normal};
+use rpc::{client, context, server::Server};
+use std::{
+    io,
+    time::{Duration, Instant, SystemTime},
+};
+use tokio::timer::Delay;
+
+pub trait AsDuration {
+    /// Delay of 0 if self is in the past
+    fn as_duration(&self) -> Duration;
+}
+
+impl AsDuration for SystemTime {
+    fn as_duration(&self) -> Duration {
+        self.duration_since(SystemTime::now()).unwrap_or_default()
+    }
+}
+
+async fn run() -> io::Result<()> {
+    let listener = tarpc_bincode_transport::listen(&"0.0.0.0:0".parse().unwrap())?;
+    let addr = listener.local_addr();
+    let server = Server::<String, String>::default()
+        .incoming(listener)
+        .take(1)
+        .for_each(async move |channel| {
+            let channel = if let Ok(channel) = channel {
+                channel
+            } else {
+                return;
+            };
+            let client_addr = *channel.client_addr();
+            let handler = channel.respond_with(move |ctx, request| {
+                // Sleep for a time sampled from a normal distribution with:
+                // - mean: 1/2 the deadline.
+                // - std dev: 1/2 the deadline.
+                let deadline: Duration = ctx.deadline.as_duration();
+                let deadline_millis = deadline.as_secs() * 1000 + deadline.subsec_millis() as u64;
+                let distribution =
+                    Normal::new(deadline_millis as f64 / 2., deadline_millis as f64 / 2.);
+                let delay_millis = distribution.sample(&mut rand::thread_rng()).max(0.);
+                let delay = Duration::from_millis(delay_millis as u64);
+
+                trace!(
+                    "[{}/{}] Responding to request in {:?}.",
+                    ctx.trace_id(),
+                    client_addr,
+                    delay,
+                );
+
+                let sleep = Delay::new(Instant::now() + delay).compat();
+                async {
+                    await!(sleep).unwrap();
+                    Ok(request)
+                }
+            });
+            tokio_executor::spawn(handler.unit_error().boxed().compat());
+        });
+
+    tokio_executor::spawn(server.unit_error().boxed().compat());
+
+    let mut config = client::Config::default();
+    config.max_in_flight_requests = 10;
+    config.pending_request_buffer = 10;
+
+    let conn = await!(tarpc_bincode_transport::connect(&addr))?;
+    let client = await!(client::new::<String, String, _>(config, conn))?;
+
+    let clients = (1..=100u32).map(|_| client.clone()).collect::<Vec<_>>();
+    for mut client in clients {
+        let ctx = context::current();
+        tokio_executor::spawn(
+            async move {
+                let trace_id = *ctx.trace_id();
+                let response = client.call(ctx, "ping".into());
+                match await!(response) {
+                    Ok(response) => info!("[{}] response: {}", trace_id, response),
+                    Err(e) => error!("[{}] request error: {:?}: {}", trace_id, e.kind(), e),
+                }
+            }
+                .unit_error()
+                .boxed()
+                .compat(),
+        );
+    }
+
+    Ok(())
+}
+
+#[test]
+fn ping_pong() -> io::Result<()> {
+    env_logger::init();
+    rpc::init(TokioDefaultSpawner);
+
+    tokio::run(
+        run()
+            .map_ok(|_| println!("done"))
+            .map_err(|e| panic!(e.to_string()))
+            .boxed()
+            .compat(),
+    );
+
+    Ok(())
+}

example-service/Cargo.toml

@@ -0,0 +1,36 @@
+cargo-features = ["rename-dependency"]
+
+[package]
+name = "tarpc-example-service"
+version = "0.2.0"
+authors = ["Tim Kuehn <tikue@google.com>"]
+edition = "2018"
+license = "MIT"
+documentation = "https://docs.rs/tarpc-example-service"
+homepage = "https://github.com/google/tarpc"
+repository = "https://github.com/google/tarpc"
+keywords = ["rpc", "network", "server", "microservices", "example"]
+categories = ["asynchronous", "network-programming"]
+readme = "../README.md"
+description = "An example server built on tarpc."
+
+[dependencies]
+bincode-transport = { package = "tarpc-bincode-transport", version = "0.3", path = "../bincode-transport" }
+clap = "2.0"
+futures-preview = { version = "0.3.0-alpha.9", features = ["compat", "tokio-compat"] }
+serde = { version = "1.0" }
+tarpc = { version = "0.14", path = "../tarpc", features = ["serde1"] }
+tokio = "0.1"
+tokio-executor = "0.1"
+
+[lib]
+name = "service"
+path = "src/lib.rs"
+
+[[bin]]
+name = "server"
+path = "src/server.rs"
+
+[[bin]]
+name = "client"
+path = "src/client.rs"

example-service/src/client.rs

@@ -0,0 +1,79 @@
+// Copyright 2018 Google LLC
+//
+// Use of this source code is governed by an MIT-style
+// license that can be found in the LICENSE file or at
+// https://opensource.org/licenses/MIT.
+
+#![feature(
+    futures_api,
+    pin,
+    arbitrary_self_types,
+    await_macro,
+    async_await
+)]
+
+use clap::{App, Arg};
+use futures::{compat::TokioDefaultSpawner, prelude::*};
+use std::{io, net::SocketAddr};
+use tarpc::{client, context};
+
+async fn run(server_addr: SocketAddr, name: String) -> io::Result<()> {
+    let transport = await!(bincode_transport::connect(&server_addr))?;
+
+    // new_stub is generated by the service! macro. Like Server, it takes a config and any
+    // Transport as input, and returns a Client, also generated by the macro.
+    // by the service mcro.
+    let mut client = await!(service::new_stub(client::Config::default(), transport))?;
+
+    // The client has an RPC method for each RPC defined in service!. It takes the same args
+    // as defined, with the addition of a Context, which is always the first arg. The Context
+    // specifies a deadline and trace information which can be helpful in debugging requests.
+    let hello = await!(client.hello(context::current(), name))?;
+
+    println!("{}", hello);
+
+    Ok(())
+}
+
+fn main() {
+    let flags = App::new("Hello Client")
+        .version("0.1")
+        .author("Tim <tikue@google.com>")
+        .about("Say hello!")
+        .arg(
+            Arg::with_name("server_addr")
+                .long("server_addr")
+                .value_name("ADDRESS")
+                .help("Sets the server address to connect to.")
+                .required(true)
+                .takes_value(true),
+        )
+        .arg(
+            Arg::with_name("name")
+                .short("n")
+                .long("name")
+                .value_name("STRING")
+                .help("Sets the name to say hello to.")
+                .required(true)
+                .takes_value(true),
+        )
+        .get_matches();
+
+    tarpc::init(TokioDefaultSpawner);
+
+    let server_addr = flags.value_of("server_addr").unwrap();
+    let server_addr = server_addr
+        .parse()
+        .unwrap_or_else(|e| panic!(r#"--server_addr value "{}" invalid: {}"#, server_addr, e));
+
+    let name = flags.value_of("name").unwrap();
+
+    tarpc::init(TokioDefaultSpawner);
+
+    tokio::run(
+        run(server_addr, name.into())
+            .map_err(|e| eprintln!("Oh no: {}", e))
+            .boxed()
+            .compat(),
+    );
+}

example-service/src/lib.rs

@@ -0,0 +1,21 @@
+// Copyright 2018 Google LLC
+//
+// Use of this source code is governed by an MIT-style
+// license that can be found in the LICENSE file or at
+// https://opensource.org/licenses/MIT.
+
+#![feature(
+    futures_api,
+    pin,
+    arbitrary_self_types,
+    await_macro,
+    async_await,
+    proc_macro_hygiene
+)]
+
+// This is the service definition. It looks a lot like a trait definition.
+// It defines one RPC, hello, which takes one arg, name, and returns a String.
+tarpc::service! {
+    /// Returns a greeting for name.
+    rpc hello(name: String) -> String;
+}

example-service/src/server.rs

@@ -0,0 +1,90 @@
+// Copyright 2018 Google LLC
+//
+// Use of this source code is governed by an MIT-style
+// license that can be found in the LICENSE file or at
+// https://opensource.org/licenses/MIT.
+
+#![feature(
+    futures_api,
+    pin,
+    arbitrary_self_types,
+    await_macro,
+    async_await
+)]
+
+use clap::{App, Arg};
+use futures::{
+    compat::TokioDefaultSpawner,
+    future::{self, Ready},
+    prelude::*,
+};
+use std::{io, net::SocketAddr};
+use tarpc::{
+    context,
+    server::{Handler, Server},
+};
+
+// This is the type that implements the generated Service trait. It is the business logic
+// and is used to start the server.
+#[derive(Clone)]
+struct HelloServer;
+
+impl service::Service for HelloServer {
+    // Each defined rpc generates two items in the trait, a fn that serves the RPC, and
+    // an associated type representing the future output by the fn.
+
+    type HelloFut = Ready<String>;
+
+    fn hello(self, _: context::Context, name: String) -> Self::HelloFut {
+        future::ready(format!("Hello, {}!", name))
+    }
+}
+
+async fn run(server_addr: SocketAddr) -> io::Result<()> {
+    // bincode_transport is provided by the associated crate bincode-transport. It makes it easy
+    // to start up a serde-powered bincode serialization strategy over TCP.
+    let transport = bincode_transport::listen(&server_addr)?;
+
+    // The server is configured with the defaults.
+    let server = Server::default()
+        // Server can listen on any type that implements the Transport trait.
+        .incoming(transport)
+        // serve is generated by the service! macro. It takes as input any type implementing
+        // the generated Service trait.
+        .respond_with(service::serve(HelloServer));
+
+    await!(server);
+
+    Ok(())
+}
+
+fn main() {
+    let flags = App::new("Hello Server")
+        .version("0.1")
+        .author("Tim <tikue@google.com>")
+        .about("Say hello!")
+        .arg(
+            Arg::with_name("port")
+                .short("p")
+                .long("port")
+                .value_name("NUMBER")
+                .help("Sets the port number to listen on")
+                .required(true)
+                .takes_value(true),
+        )
+        .get_matches();
+
+    let port = flags.value_of("port").unwrap();
+    let port = port
+        .parse()
+        .unwrap_or_else(|e| panic!(r#"--port value "{}" invalid: {}"#, port, e));
+
+    tarpc::init(TokioDefaultSpawner);
+
+    tokio::run(
+        run(([0, 0, 0, 0], port).into())
+            .map_err(|e| eprintln!("Oh no: {}", e))
+            .boxed()
+            .compat(),
+    );
+}

examples/concurrency.rs

@@ -1,208 +0,0 @@
-// Copyright 2016 Google Inc. All Rights Reserved.
-//
-// Licensed under the MIT License, <LICENSE or http://opensource.org/licenses/MIT>.
-// This file may not be copied, modified, or distributed except according to those terms.
-
-#![feature(plugin, never_type, use_extern_macros, proc_macro_path_invoc)]
-#![plugin(tarpc_plugins)]
-
-extern crate chrono;
-extern crate clap;
-extern crate env_logger;
-extern crate futures;
-#[macro_use]
-extern crate log;
-extern crate serde_bytes;
-#[macro_use]
-extern crate tarpc;
-extern crate tokio_core;
-extern crate futures_cpupool;
-
-use clap::{Arg, App};
-use futures::{Future, Stream};
-use futures_cpupool::{CpuFuture, CpuPool};
-use std::{cmp, thread};
-use std::sync::{Arc, mpsc};
-use std::sync::atomic::{AtomicUsize, Ordering};
-use std::time::{Duration, Instant};
-use tarpc::future::{client, server};
-use tarpc::future::client::ClientExt;
-use tarpc::util::{FirstSocketAddr, Never};
-use tokio_core::reactor;
-
-service! {
-    rpc read(size: u32) -> serde_bytes::ByteBuf;
-}
-
-#[derive(Clone)]
-struct Server {
-    pool: CpuPool,
-    request_count: Arc<AtomicUsize>,
-}
-
-impl Server {
-    fn new() -> Self {
-        Server {
-            pool: CpuPool::new_num_cpus(),
-            request_count: Arc::new(AtomicUsize::new(1)),
-        }
-    }
-}
-
-impl FutureService for Server {
-    type ReadFut = CpuFuture<serde_bytes::ByteBuf, Never>;
-
-    fn read(&self, size: u32) -> Self::ReadFut {
-        let request_number = self.request_count.fetch_add(1, Ordering::SeqCst);
-        debug!("Server received read({}) no. {}", size, request_number);
-        self.pool.spawn(futures::lazy(move || {
-            let mut vec = Vec::with_capacity(size as usize);
-            for i in 0..size {
-                vec.push(((i % 2) << 8) as u8);
-            }
-            debug!("Server sending response no. {}", request_number);
-            Ok(vec.into())
-        }))
-    }
-}
-
-const CHUNK_SIZE: u32 = 1 << 10;
-
-trait Microseconds {
-    fn microseconds(&self) -> i64;
-}
-
-impl Microseconds for Duration {
-    fn microseconds(&self) -> i64 {
-        chrono::Duration::from_std(*self)
-            .unwrap()
-            .num_microseconds()
-            .unwrap()
-    }
-}
-
-#[derive(Default)]
-struct Stats {
-    sum: Duration,
-    count: u64,
-    min: Option<Duration>,
-    max: Option<Duration>,
-}
-
-/// Spawns a `reactor::Core` running forever on a new thread.
-fn spawn_core() -> reactor::Remote {
-    let (tx, rx) = mpsc::channel();
-    thread::spawn(move || {
-        let mut core = reactor::Core::new().unwrap();
-        tx.send(core.handle().remote().clone()).unwrap();
-
-        // Run forever
-        core.run(futures::empty::<(), !>()).unwrap();
-    });
-    rx.recv().unwrap()
-}
-
-fn run_once(
-    clients: Vec<FutureClient>,
-    concurrency: u32,
-) -> impl Future<Item = (), Error = ()> + 'static {
-    let start = Instant::now();
-    futures::stream::futures_unordered(
-        (0..concurrency as usize)
-            .zip(clients.iter().enumerate().cycle())
-            .map(|(iteration, (client_idx, client))| {
-                let start = Instant::now();
-                debug!("Client {} reading (iteration {})...", client_idx, iteration);
-                client
-                    .read(CHUNK_SIZE)
-                    .map(move |_| (client_idx, iteration, start))
-            }),
-    ).map(|(client_idx, iteration, start)| {
-        let elapsed = start.elapsed();
-        debug!(
-            "Client {} received reply (iteration {}).",
-            client_idx,
-            iteration
-        );
-        elapsed
-    })
-        .map_err(|e| panic!(e))
-        .fold(Stats::default(), move |mut stats, elapsed| {
-            stats.sum += elapsed;
-            stats.count += 1;
-            stats.min = Some(cmp::min(stats.min.unwrap_or(elapsed), elapsed));
-            stats.max = Some(cmp::max(stats.max.unwrap_or(elapsed), elapsed));
-            Ok(stats)
-        })
-        .map(move |stats| {
-            info!(
-                "{} requests => Mean={}µs, Min={}µs, Max={}µs, Total={}µs",
-                stats.count,
-                stats.sum.microseconds() as f64 / stats.count as f64,
-                stats.min.unwrap().microseconds(),
-                stats.max.unwrap().microseconds(),
-                start.elapsed().microseconds()
-            );
-        })
-}
-
-fn main() {
-    env_logger::init();
-    let matches = App::new("Tarpc Concurrency")
-        .about(
-            "Demonstrates making concurrent requests to a tarpc service.",
-        )
-        .arg(
-            Arg::with_name("concurrency")
-                .short("c")
-                .long("concurrency")
-                .value_name("LEVEL")
-                .help("Sets a custom concurrency level")
-                .takes_value(true),
-        )
-        .arg(
-            Arg::with_name("clients")
-                .short("n")
-                .long("num_clients")
-                .value_name("AMOUNT")
-                .help("How many clients to distribute requests between")
-                .takes_value(true),
-        )
-        .get_matches();
-    let concurrency = matches
-        .value_of("concurrency")
-        .map(&str::parse)
-        .map(Result::unwrap)
-        .unwrap_or(10);
-    let num_clients = matches
-        .value_of("clients")
-        .map(&str::parse)
-        .map(Result::unwrap)
-        .unwrap_or(4);
-
-    let mut reactor = reactor::Core::new().unwrap();
-    let (handle, server) = Server::new()
-        .listen(
-            "localhost:0".first_socket_addr(),
-            &reactor.handle(),
-            server::Options::default(),
-        )
-        .unwrap();
-    reactor.handle().spawn(server);
-    info!("Server listening on {}.", handle.addr());
-
-    let clients = (0..num_clients)
-        // Spin up a couple threads to drive the clients.
-        .map(|i| (i, spawn_core()))
-        .map(|(i, remote)| {
-            info!("Client {} connecting...", i);
-            FutureClient::connect(handle.addr(), client::Options::default().remote(remote))
-                .map_err(|e| panic!(e))
-        });
-
-    let run = futures::collect(clients).and_then(|clients| run_once(clients, concurrency));
-
-    info!("Starting...");
-
-    reactor.run(run).unwrap();
-}

examples/pubsub.rs

@@ -1,160 +0,0 @@
-// Copyright 2016 Google Inc. All Rights Reserved.
-//
-// Licensed under the MIT License, <LICENSE or http://opensource.org/licenses/MIT>.
-// This file may not be copied, modified, or distributed except according to those terms.
-
-#![feature(plugin, use_extern_macros, proc_macro_path_invoc)]
-#![plugin(tarpc_plugins)]
-
-extern crate env_logger;
-extern crate futures;
-#[macro_use]
-extern crate tarpc;
-extern crate tokio_core;
-
-use futures::{Future, future};
-use publisher::FutureServiceExt as PublisherExt;
-use std::cell::RefCell;
-use std::collections::HashMap;
-use std::net::SocketAddr;
-use std::rc::Rc;
-use std::thread;
-use std::time::Duration;
-use subscriber::FutureServiceExt as SubscriberExt;
-use tarpc::future::{client, server};
-use tarpc::future::client::ClientExt;
-use tarpc::util::{FirstSocketAddr, Message, Never};
-use tokio_core::reactor;
-
-pub mod subscriber {
-    service! {
-        rpc receive(message: String);
-    }
-}
-
-pub mod publisher {
-    use std::net::SocketAddr;
-    use tarpc::util::Message;
-
-    service! {
-        rpc broadcast(message: String);
-        rpc subscribe(id: u32, address: SocketAddr) | Message;
-        rpc unsubscribe(id: u32);
-    }
-}
-
-#[derive(Clone, Debug)]
-struct Subscriber {
-    id: u32,
-}
-
-impl subscriber::FutureService for Subscriber {
-    type ReceiveFut = Result<(), Never>;
-
-    fn receive(&self, message: String) -> Self::ReceiveFut {
-        println!("{} received message: {}", self.id, message);
-        Ok(())
-    }
-}
-
-impl Subscriber {
-    fn listen(id: u32, handle: &reactor::Handle, options: server::Options) -> server::Handle {
-        let (server_handle, server) = Subscriber { id: id }
-            .listen("localhost:0".first_socket_addr(), handle, options)
-            .unwrap();
-        handle.spawn(server);
-        server_handle
-    }
-}
-
-#[derive(Clone, Debug)]
-struct Publisher {
-    clients: Rc<RefCell<HashMap<u32, subscriber::FutureClient>>>,
-}
-
-impl Publisher {
-    fn new() -> Publisher {
-        Publisher {
-            clients: Rc::new(RefCell::new(HashMap::new())),
-        }
-    }
-}
-
-impl publisher::FutureService for Publisher {
-    type BroadcastFut = Box<Future<Item = (), Error = Never>>;
-
-    fn broadcast(&self, message: String) -> Self::BroadcastFut {
-        let acks = self.clients
-                       .borrow()
-                       .values()
-                       .map(move |client| client.receive(message.clone())
-                           // Ignore failing subscribers. In a real pubsub,
-                           // you'd want to continually retry until subscribers
-                           // ack.
-                           .then(|_| Ok(())))
-                       // Collect to a vec to end the borrow on `self.clients`.
-                       .collect::<Vec<_>>();
-        Box::new(future::join_all(acks).map(|_| ()))
-    }
-
-    type SubscribeFut = Box<Future<Item = (), Error = Message>>;
-
-    fn subscribe(&self, id: u32, address: SocketAddr) -> Self::SubscribeFut {
-        let clients = Rc::clone(&self.clients);
-        Box::new(
-            subscriber::FutureClient::connect(address, client::Options::default())
-                .map(move |subscriber| {
-                    println!("Subscribing {}.", id);
-                    clients.borrow_mut().insert(id, subscriber);
-                    ()
-                })
-                .map_err(|e| e.to_string().into()),
-        )
-    }
-
-    type UnsubscribeFut = Box<Future<Item = (), Error = Never>>;
-
-    fn unsubscribe(&self, id: u32) -> Self::UnsubscribeFut {
-        println!("Unsubscribing {}", id);
-        self.clients.borrow_mut().remove(&id).unwrap();
-        Box::new(futures::finished(()))
-    }
-}
-
-fn main() {
-    env_logger::init();
-    let mut reactor = reactor::Core::new().unwrap();
-    let (publisher_handle, server) = Publisher::new()
-        .listen(
-            "localhost:0".first_socket_addr(),
-            &reactor.handle(),
-            server::Options::default(),
-        )
-        .unwrap();
-    reactor.handle().spawn(server);
-
-    let subscriber1 = Subscriber::listen(0, &reactor.handle(), server::Options::default());
-    let subscriber2 = Subscriber::listen(1, &reactor.handle(), server::Options::default());
-
-    let publisher = reactor
-        .run(publisher::FutureClient::connect(
-            publisher_handle.addr(),
-            client::Options::default(),
-        ))
-        .unwrap();
-    reactor
-        .run(
-            publisher
-                .subscribe(0, subscriber1.addr())
-                .and_then(|_| publisher.subscribe(1, subscriber2.addr()))
-                .map_err(|e| panic!(e))
-                .and_then(|_| {
-                    println!("Broadcasting...");
-                    publisher.broadcast("hello to all".to_string())
-                })
-                .and_then(|_| publisher.unsubscribe(1))
-                .and_then(|_| publisher.broadcast("hi again".to_string())),
-        )
-        .unwrap();
-    thread::sleep(Duration::from_millis(300));
-}

examples/readme_errors.rs

@@ -1,65 +0,0 @@
-// Copyright 2016 Google Inc. All Rights Reserved.
-//
-// Licensed under the MIT License, <LICENSE or http://opensource.org/licenses/MIT>.
-// This file may not be copied, modified, or distributed except according to those terms.
-
-#![feature(plugin, use_extern_macros, proc_macro_path_invoc)]
-#![plugin(tarpc_plugins)]
-
-#[macro_use]
-extern crate tarpc;
-#[macro_use]
-extern crate serde_derive;
-
-use std::error::Error;
-use std::fmt;
-use std::sync::mpsc;
-use std::thread;
-use tarpc::sync::{client, server};
-use tarpc::sync::client::ClientExt;
-
-service! {
-    rpc hello(name: String) -> String | NoNameGiven;
-}
-
-#[derive(Debug, Deserialize, Serialize)]
-pub struct NoNameGiven;
-
-impl fmt::Display for NoNameGiven {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        write!(f, "{}", self.description())
-    }
-}
-
-impl Error for NoNameGiven {
-    fn description(&self) -> &str {
-        r#"The empty String, "", is not a valid argument to rpc `hello`."#
-    }
-}
-
-#[derive(Clone)]
-struct HelloServer;
-
-impl SyncService for HelloServer {
-    fn hello(&self, name: String) -> Result<String, NoNameGiven> {
-        if name == "" {
-            Err(NoNameGiven)
-        } else {
-            Ok(format!("Hello, {}!", name))
-        }
-    }
-}
-
-fn main() {
-    let (tx, rx) = mpsc::channel();
-    thread::spawn(move || {
-        let handle = HelloServer
-            .listen("localhost:10000", server::Options::default())
-            .unwrap();
-        tx.send(handle.addr()).unwrap();
-        handle.run();
-    });
-    let client = SyncClient::connect(rx.recv().unwrap(), client::Options::default()).unwrap();
-    println!("{}", client.hello("Mom".to_string()).unwrap());
-    println!("{}", client.hello("".to_string()).unwrap_err());
-}

examples/readme_futures.rs

@@ -1,55 +0,0 @@
-// Copyright 2016 Google Inc. All Rights Reserved.
-//
-// Licensed under the MIT License, <LICENSE or http://opensource.org/licenses/MIT>.
-// This file may not be copied, modified, or distributed except according to those terms.
-
-#![feature(plugin, use_extern_macros, proc_macro_path_invoc)]
-#![plugin(tarpc_plugins)]
-
-extern crate futures;
-#[macro_use]
-extern crate tarpc;
-extern crate tokio_core;
-
-use futures::Future;
-use tarpc::future::{client, server};
-use tarpc::future::client::ClientExt;
-use tarpc::util::{FirstSocketAddr, Never};
-use tokio_core::reactor;
-
-service! {
-    rpc hello(name: String) -> String;
-}
-
-#[derive(Clone)]
-struct HelloServer;
-
-impl FutureService for HelloServer {
-    type HelloFut = Result<String, Never>;
-
-    fn hello(&self, name: String) -> Self::HelloFut {
-        Ok(format!("Hello, {}!", name))
-    }
-}
-
-fn main() {
-    let mut reactor = reactor::Core::new().unwrap();
-    let (handle, server) = HelloServer
-        .listen(
-            "localhost:10000".first_socket_addr(),
-            &reactor.handle(),
-            server::Options::default(),
-        )
-        .unwrap();
-    reactor.handle().spawn(server);
-
-    let options = client::Options::default().handle(reactor.handle());
-    reactor
-        .run(
-            FutureClient::connect(handle.addr(), options)
-                .map_err(tarpc::Error::from)
-                .and_then(|client| client.hello("Mom".to_string()))
-                .map(|resp| println!("{}", resp)),
-        )
-        .unwrap();
-}

examples/readme_sync.rs

@@ -1,47 +0,0 @@
-// Copyright 2016 Google Inc. All Rights Reserved.
-//
-// Licensed under the MIT License, <LICENSE or http://opensource.org/licenses/MIT>.
-// This file may not be copied, modified, or distributed except according to those terms.
-
-// required by `FutureClient` (not used directly in this example)
-#![feature(plugin, use_extern_macros, proc_macro_path_invoc)]
-#![plugin(tarpc_plugins)]
-
-#[macro_use]
-extern crate tarpc;
-
-use std::sync::mpsc;
-use std::thread;
-use tarpc::sync::{client, server};
-use tarpc::sync::client::ClientExt;
-use tarpc::util::Never;
-
-service! {
-    rpc hello(name: String) -> String;
-}
-
-#[derive(Clone)]
-struct HelloServer;
-
-impl SyncService for HelloServer {
-    fn hello(&self, name: String) -> Result<String, Never> {
-        Ok(format!(
-            "Hello from thread {}, {}!",
-            thread::current().name().unwrap(),
-            name
-        ))
-    }
-}
-
-fn main() {
-    let (tx, rx) = mpsc::channel();
-    thread::spawn(move || {
-        let handle = HelloServer
-            .listen("localhost:0", server::Options::default())
-            .unwrap();
-        tx.send(handle.addr()).unwrap();
-        handle.run();
-    });
-    let client = SyncClient::connect(rx.recv().unwrap(), client::Options::default()).unwrap();
-    println!("{}", client.hello("Mom".to_string()).unwrap());
-}

examples/server_calling_server.rs

@@ -1,113 +0,0 @@
-// Copyright 2016 Google Inc. All Rights Reserved.
-//
-// Licensed under the MIT License, <LICENSE or http://opensource.org/licenses/MIT>.
-// This file may not be copied, modified, or distributed except according to those terms.
-
-#![feature(plugin, use_extern_macros, proc_macro_path_invoc)]
-#![plugin(tarpc_plugins)]
-
-extern crate env_logger;
-#[macro_use]
-extern crate tarpc;
-extern crate futures;
-extern crate tokio_core;
-
-use add::{FutureService as AddFutureService, FutureServiceExt as AddExt};
-use double::{FutureService as DoubleFutureService, FutureServiceExt as DoubleExt};
-use futures::{Future, Stream};
-use tarpc::future::{client, server};
-use tarpc::future::client::ClientExt as Fc;
-use tarpc::util::{FirstSocketAddr, Message, Never};
-use tokio_core::reactor;
-
-pub mod add {
-    service! {
-        /// Add two ints together.
-        rpc add(x: i32, y: i32) -> i32;
-    }
-}
-
-pub mod double {
-    use tarpc::util::Message;
-
-    service! {
-        /// 2 * x
-        rpc double(x: i32) -> i32 | Message;
-    }
-}
-
-#[derive(Clone)]
-struct AddServer;
-
-impl AddFutureService for AddServer {
-    type AddFut = Result<i32, Never>;
-
-    fn add(&self, x: i32, y: i32) -> Self::AddFut {
-        Ok(x + y)
-    }
-}
-
-#[derive(Clone)]
-struct DoubleServer {
-    client: add::FutureClient,
-}
-
-impl DoubleServer {
-    fn new(client: add::FutureClient) -> Self {
-        DoubleServer { client: client }
-    }
-}
-
-impl DoubleFutureService for DoubleServer {
-    type DoubleFut = Box<Future<Item=i32, Error=Message>>;
-
-    fn double(&self, x: i32) -> Self::DoubleFut {
-        Box::new(self.client
-            .add(x, x)
-            .map_err(|e| e.to_string().into()))
-    }
-}
-
-fn main() {
-    env_logger::init();
-    let mut reactor = reactor::Core::new().unwrap();
-    let (add, server) = AddServer
-        .listen(
-            "localhost:0".first_socket_addr(),
-            &reactor.handle(),
-            server::Options::default(),
-        )
-        .unwrap();
-    reactor.handle().spawn(server);
-
-    let options = client::Options::default().handle(reactor.handle());
-    let add_client = reactor
-        .run(add::FutureClient::connect(add.addr(), options))
-        .unwrap();
-
-    let (double, server) = DoubleServer::new(add_client)
-        .listen(
-            "localhost:0".first_socket_addr(),
-            &reactor.handle(),
-            server::Options::default(),
-        )
-        .unwrap();
-    reactor.handle().spawn(server);
-
-    let double_client = reactor
-        .run(double::FutureClient::connect(
-            double.addr(),
-            client::Options::default(),
-        ))
-        .unwrap();
-    reactor
-        .run(
-            futures::stream::futures_unordered((0..5).map(|i| double_client.double(i)))
-                .map_err(|e| println!("{}", e))
-                .for_each(|i| {
-                    println!("{:?}", i);
-                    Ok(())
-                }),
-        )
-        .unwrap();
-}

examples/sync_server_calling_server.rs

@@ -1,98 +0,0 @@
-// Copyright 2016 Google Inc. All Rights Reserved.
-//
-// Licensed under the MIT License, <LICENSE or http://opensource.org/licenses/MIT>.
-// This file may not be copied, modified, or distributed except according to those terms.
-
-#![feature(plugin, use_extern_macros, proc_macro_path_invoc)]
-#![plugin(tarpc_plugins)]
-
-extern crate env_logger;
-#[macro_use]
-extern crate tarpc;
-
-use add::{SyncService as AddSyncService, SyncServiceExt as AddExt};
-use double::{SyncService as DoubleSyncService, SyncServiceExt as DoubleExt};
-use std::sync::mpsc;
-use std::thread;
-use tarpc::sync::{client, server};
-use tarpc::sync::client::ClientExt as Fc;
-use tarpc::util::{FirstSocketAddr, Message, Never};
-
-pub mod add {
-    service! {
-        /// Add two ints together.
-        rpc add(x: i32, y: i32) -> i32;
-    }
-}
-
-pub mod double {
-    use tarpc::util::Message;
-
-    service! {
-        /// 2 * x
-        rpc double(x: i32) -> i32 | Message;
-    }
-}
-
-#[derive(Clone)]
-struct AddServer;
-
-impl AddSyncService for AddServer {
-    fn add(&self, x: i32, y: i32) -> Result<i32, Never> {
-        Ok(x + y)
-    }
-}
-
-#[derive(Clone)]
-struct DoubleServer {
-    client: add::SyncClient,
-}
-
-impl DoubleServer {
-    fn new(client: add::SyncClient) -> Self {
-        DoubleServer { client: client }
-    }
-}
-
-impl DoubleSyncService for DoubleServer {
-    fn double(&self, x: i32) -> Result<i32, Message> {
-        self.client.add(x, x).map_err(|e| e.to_string().into())
-    }
-}
-
-fn main() {
-    env_logger::init();
-    let (tx, rx) = mpsc::channel();
-    thread::spawn(move || {
-        let handle = AddServer
-            .listen(
-                "localhost:0".first_socket_addr(),
-                server::Options::default(),
-            )
-            .unwrap();
-        tx.send(handle.addr()).unwrap();
-        handle.run();
-    });
-
-
-    let add = rx.recv().unwrap();
-    let (tx, rx) = mpsc::channel();
-    thread::spawn(move || {
-        let add_client = add::SyncClient::connect(add, client::Options::default()).unwrap();
-        let handle = DoubleServer::new(add_client)
-            .listen(
-                "localhost:0".first_socket_addr(),
-                server::Options::default(),
-            )
-            .unwrap();
-        tx.send(handle.addr()).unwrap();
-        handle.run();
-    });
-    let double = rx.recv().unwrap();
-
-    let double_client = double::SyncClient::connect(double, client::Options::default()).unwrap();
-    for i in 0..5 {
-        let doubled = double_client.double(i).unwrap();
-        println!("{:?}", doubled);
-    }
-}

examples/throughput.rs

@@ -1,119 +0,0 @@
-// Copyright 2016 Google Inc. All Rights Reserved.
-//
-// Licensed under the MIT License, <LICENSE or http://opensource.org/licenses/MIT>.
-// This file may not be copied, modified, or distributed except according to those terms.
-
-#![feature(plugin, use_extern_macros, proc_macro_path_invoc)]
-#![plugin(tarpc_plugins)]
-
-#[macro_use]
-extern crate lazy_static;
-#[macro_use]
-extern crate tarpc;
-extern crate env_logger;
-extern crate serde_bytes;
-extern crate tokio_core;
-
-use std::io::{Read, Write, stdout};
-use std::net;
-use std::sync::mpsc;
-use std::thread;
-use std::time;
-use tarpc::future::server;
-use tarpc::sync::client::{self, ClientExt};
-use tarpc::util::{FirstSocketAddr, Never};
-use tokio_core::reactor;
-
-lazy_static! {
-    static ref BUF: serde_bytes::ByteBuf = gen_vec(CHUNK_SIZE as usize).into();
-}
-
-fn gen_vec(size: usize) -> Vec<u8> {
-    let mut vec: Vec<u8> = Vec::with_capacity(size);
-    for i in 0..size {
-        vec.push(((i % 2) << 8) as u8);
-    }
-    vec
-}
-
-service! {
-    rpc read() -> serde_bytes::ByteBuf;
-}
-
-#[derive(Clone)]
-struct Server;
-
-impl FutureService for Server {
-    type ReadFut = Result<serde_bytes::ByteBuf, Never>;
-
-    fn read(&self) -> Self::ReadFut {
-        Ok(BUF.clone())
-    }
-}
-
-const CHUNK_SIZE: u32 = 1 << 19;
-
-fn bench_tarpc(target: u64) {
-    let (tx, rx) = mpsc::channel();
-    thread::spawn(move || {
-        let mut reactor = reactor::Core::new().unwrap();
-        let (addr, server) = Server
-            .listen(
-                "localhost:0".first_socket_addr(),
-                &reactor.handle(),
-                server::Options::default(),
-            )
-            .unwrap();
-        tx.send(addr).unwrap();
-        reactor.run(server).unwrap();
-    });
-    let client =
-        SyncClient::connect(rx.recv().unwrap().addr(), client::Options::default()).unwrap();
-    let start = time::Instant::now();
-    let mut nread = 0;
-    while nread < target {
-        nread += client.read().unwrap().len() as u64;
-        print!(".");
-        stdout().flush().unwrap();
-    }
-    println!("done");
-    let duration = time::Instant::now() - start;
-    println!(
-        "TARPC: {}MB/s",
-        (target as f64 / (1024f64 * 1024f64)) /
-            (duration.as_secs() as f64 + duration.subsec_nanos() as f64 / 10E9)
-    );
-}
-
-fn bench_tcp(target: u64) {
-    let l = net::TcpListener::bind("localhost:0").unwrap();
-    let addr = l.local_addr().unwrap();
-    thread::spawn(move || {
-        let (mut stream, _) = l.accept().unwrap();
-        while let Ok(_) = stream.write_all(&*BUF) {}
-    });
-    let mut stream = net::TcpStream::connect(&addr).unwrap();
-    let mut buf = vec![0; CHUNK_SIZE as usize];
-    let start = time::Instant::now();
-    let mut nread = 0;
-    while nread < target {
-        stream.read_exact(&mut buf[..]).unwrap();
-        nread += CHUNK_SIZE as u64;
-        print!(".");
-        stdout().flush().unwrap();
-    }
-    println!("done");
-    let duration = time::Instant::now() - start;
-    println!(
-        "TCP:   {}MB/s",
-        (target as f64 / (1024f64 * 1024f64)) /
-            (duration.as_secs() as f64 + duration.subsec_nanos() as f64 / 10E9)
-    );
-}
-
-fn main() {
-    env_logger::init();
-    let _ = *BUF; // To non-lazily initialize it.
-    bench_tcp(256 << 20);
-    bench_tarpc(256 << 20);
-}

examples/two_clients.rs

@@ -1,105 +0,0 @@
-// Copyright 2016 Google Inc. All Rights Reserved.
-//
-// Licensed under the MIT License, <LICENSE or http://opensource.org/licenses/MIT>.
-// This file may not be copied, modified, or distributed except according to those terms.
-
-#![feature(plugin, use_extern_macros, proc_macro_path_invoc)]
-#![plugin(tarpc_plugins)]
-
-#[macro_use]
-extern crate log;
-#[macro_use]
-extern crate tarpc;
-extern crate env_logger;
-extern crate tokio_core;
-
-use bar::FutureServiceExt as BarExt;
-use baz::FutureServiceExt as BazExt;
-use std::sync::mpsc;
-use std::thread;
-use tarpc::future::server;
-use tarpc::sync::client;
-use tarpc::sync::client::ClientExt;
-use tarpc::util::{FirstSocketAddr, Never};
-use tokio_core::reactor;
-
-mod bar {
-    service! {
-        rpc bar(i: i32) -> i32;
-    }
-}
-
-#[derive(Clone)]
-struct Bar;
-impl bar::FutureService for Bar {
-    type BarFut = Result<i32, Never>;
-
-    fn bar(&self, i: i32) -> Self::BarFut {
-        Ok(i)
-    }
-}
-
-mod baz {
-    service! {
-        rpc baz(s: String) -> String;
-    }
-}
-
-#[derive(Clone)]
-struct Baz;
-impl baz::FutureService for Baz {
-    type BazFut = Result<String, Never>;
-
-    fn baz(&self, s: String) -> Self::BazFut {
-        Ok(format!("Hello, {}!", s))
-    }
-}
-
-fn main() {
-    env_logger::init();
-    let bar_client = {
-        let (tx, rx) = mpsc::channel();
-        thread::spawn(move || {
-            let mut reactor = reactor::Core::new().unwrap();
-            let (handle, server) = Bar.listen(
-                "localhost:0".first_socket_addr(),
-                &reactor.handle(),
-                server::Options::default(),
-            ).unwrap();
-            tx.send(handle).unwrap();
-            reactor.run(server).unwrap();
-        });
-        let handle = rx.recv().unwrap();
-        bar::SyncClient::connect(handle.addr(), client::Options::default()).unwrap()
-    };
-
-    let baz_client = {
-        let (tx, rx) = mpsc::channel();
-        thread::spawn(move || {
-            let mut reactor = reactor::Core::new().unwrap();
-            let (handle, server) = Baz.listen(
-                "localhost:0".first_socket_addr(),
-                &reactor.handle(),
-                server::Options::default(),
-            ).unwrap();
-            tx.send(handle).unwrap();
-            reactor.run(server).unwrap();
-        });
-        let handle = rx.recv().unwrap();
-        baz::SyncClient::connect(handle.addr(), client::Options::default()).unwrap()
-    };
-
-
-    info!("Result: {:?}", bar_client.bar(17));
-
-    let total = 20;
-    for i in 1..(total + 1) {
-        if i % 2 == 0 {
-            info!("Result 1: {:?}", bar_client.bar(i));
-        } else {
-            info!("Result 2: {:?}", baz_client.baz(i.to_string()));
-        }
-    }
-
-    info!("Done.");
-}

hooks/pre-push

@@ -91,11 +91,8 @@ if [ "$?" == 0 ]; then
 
     try_run "Building ... " cargo build --color=always
     try_run "Testing ... " cargo test --color=always
-    try_run "Benching ... " cargo bench --color=always
+    try_run "Doc Test ... " cargo clean && cargo build --tests && rustdoc --test README.md --edition 2018 -L target/debug/deps -Z unstable-options
 
-    try_run "Building with tls ... " cargo build --color=always --features tls
-    try_run "Testing with tls ... " cargo test --color=always --features tls
-    try_run "Benching with tls ... " cargo bench --color=always --features tls
 fi
 
 exit $PREPUSH_RESULT

plugins/Cargo.toml

@@ -1,21 +1,24 @@
 [package]
 name = "tarpc-plugins"
-version = "0.4.0"
+version = "0.5.0"
 authors = ["Adam Wright <adam.austin.wright@gmail.com>", "Tim Kuehn <timothy.j.kuehn@gmail.com>"]
 license = "MIT"
-documentation = "https://docs.rs/tarpc"
+documentation = "https://docs.rs/tarpc-plugins"
 homepage = "https://github.com/google/tarpc"
 repository = "https://github.com/google/tarpc"
-keywords = ["rpc", "network", "server", "api", "tls"]
+keywords = ["rpc", "network", "server", "api", "microservices"]
 categories = ["asynchronous", "network-programming"]
-readme = "../../README.md"
-description = "Plugins for tarpc, an RPC framework for Rust with a focus on ease of use."
+readme = "../README.md"
+description = "Proc macros for tarpc."
 
 [badges]
 travis-ci = { repository = "google/tarpc" }
 
 [dependencies]
 itertools = "0.7"
+syn = { version = "0.15", features = ["full", "extra-traits"] }
+quote = "0.6"
+proc-macro2 = "0.4"
 
 [lib]
-plugin = true
+proc-macro = true

plugins/rustfmt.toml

@@ -0,0 +1 @@
+edition = "2018"

plugins/src/lib.rs

@@ -0,0 +1,90 @@
+// Copyright 2018 Google LLC
+//
+// Use of this source code is governed by an MIT-style
+// license that can be found in the LICENSE file or at
+// https://opensource.org/licenses/MIT.
+
+extern crate itertools;
+extern crate proc_macro;
+extern crate proc_macro2;
+extern crate quote;
+extern crate syn;
+
+use proc_macro::TokenStream;
+
+use itertools::Itertools;
+use proc_macro2::Span;
+use quote::ToTokens;
+use std::str::FromStr;
+use syn::{parse, Ident, TraitItemType, TypePath};
+
+#[proc_macro]
+pub fn snake_to_camel(input: TokenStream) -> TokenStream {
+    let i = input.clone();
+    let mut assoc_type = parse::<TraitItemType>(input)
+        .unwrap_or_else(|_| panic!("Could not parse trait item from:\n{}", i));
+
+    let old_ident = convert(&mut assoc_type.ident);
+
+    for mut attr in &mut assoc_type.attrs {
+        if let Some(pair) = attr.path.segments.first() {
+            if pair.value().ident == "doc" {
+                attr.tts = proc_macro2::TokenStream::from_str(
+                    &attr.tts.to_string().replace("{}", &old_ident),
+                )
+                .unwrap();
+            }
+        }
+    }
+
+    assoc_type.into_token_stream().into()
+}
+
+#[proc_macro]
+pub fn ty_snake_to_camel(input: TokenStream) -> TokenStream {
+    let mut path = parse::<TypePath>(input).unwrap();
+
+    // Only capitalize the final segment
+    convert(&mut path.path.segments.last_mut().unwrap().into_value().ident);
+
+    path.into_token_stream().into()
+}
+
+/// Converts an ident in-place to CamelCase and returns the previous ident.
+fn convert(ident: &mut Ident) -> String {
+    let ident_str = ident.to_string();
+    let mut camel_ty = String::new();
+
+    {
+        // Find the first non-underscore and add it capitalized.
+        let mut chars = ident_str.chars();
+
+        // Find the first non-underscore char, uppercase it, and append it.
+        // Guaranteed to succeed because all idents must have at least one non-underscore char.
+        camel_ty.extend(chars.find(|&c| c != '_').unwrap().to_uppercase());
+
+        // When we find an underscore, we remove it and capitalize the next char. To do this,
+        // we need to ensure the next char is not another underscore.
+        let mut chars = chars.coalesce(|c1, c2| {
+            if c1 == '_' && c2 == '_' {
+                Ok(c1)
+            } else {
+                Err((c1, c2))
+            }
+        });
+
+        while let Some(c) = chars.next() {
+            if c != '_' {
+                camel_ty.push(c);
+            } else if let Some(c) = chars.next() {
+                camel_ty.extend(c.to_uppercase());
+            }
+        }
+    }
+
+    // The Fut suffix is hardcoded right now; this macro isn't really meant to be general-purpose.
+    camel_ty.push_str("Fut");
+
+    *ident = Ident::new(&camel_ty, Span::call_site());
+    ident_str
+}

rpc/Cargo.toml

@@ -0,0 +1,38 @@
+cargo-features = ["rename-dependency"]
+
+[package]
+name = "tarpc-lib"
+version = "0.2.0"
+authors = ["Tim Kuehn <tikue@google.com>"]
+edition = '2018'
+license = "MIT"
+documentation = "https://docs.rs/tarpc-lib"
+homepage = "https://github.com/google/tarpc"
+repository = "https://github.com/google/tarpc"
+keywords = ["rpc", "network", "server", "api", "microservices"]
+categories = ["asynchronous", "network-programming"]
+readme = "../README.md"
+description = "An RPC framework for Rust with a focus on ease of use."
+
+[features]
+default = []
+serde1 = ["trace/serde", "serde", "serde/derive"]
+
+[dependencies]
+fnv = "1.0"
+humantime = "1.0"
+log = "0.4"
+pin-utils = "0.1.0-alpha.3"
+rand = "0.5"
+tokio-timer = "0.2"
+trace = { package = "tarpc-trace", version = "0.1", path = "../trace" }
+serde = { optional = true, version = "1.0" }
+
+[target.'cfg(not(test))'.dependencies]
+futures-preview = { version = "0.3.0-alpha.9", features = ["compat"] }
+
+[dev-dependencies]
+futures-preview = { version = "0.3.0-alpha.9", features = ["compat", "tokio-compat"] }
+futures-test-preview = { version = "0.3.0-alpha.9" }
+env_logger = "0.5"
+tokio = "0.1"

rpc/rustfmt.toml

@@ -0,0 +1 @@
+edition = "2018"

rpc/src/client/channel.rs

@@ -0,0 +1,945 @@
+// Copyright 2018 Google LLC
+//
+// Use of this source code is governed by an MIT-style
+// license that can be found in the LICENSE file or at
+// https://opensource.org/licenses/MIT.
+
+use crate::{
+    context,
+    util::{deadline_compat, AsDuration, Compact},
+    ClientMessage, ClientMessageKind, Request, Response, Transport,
+};
+use fnv::FnvHashMap;
+use futures::{
+    channel::{mpsc, oneshot},
+    prelude::*,
+    ready,
+    stream::Fuse,
+    task::LocalWaker,
+    Poll,
+};
+use humantime::format_rfc3339;
+use log::{debug, error, info, trace};
+use pin_utils::{unsafe_pinned, unsafe_unpinned};
+use std::{
+    io,
+    marker::{self, Unpin},
+    net::SocketAddr,
+    pin::Pin,
+    sync::{
+        atomic::{AtomicU64, Ordering},
+        Arc,
+    },
+    time::Instant,
+};
+use trace::SpanId;
+
+use super::Config;
+
+/// Handles communication from the client to request dispatch.
+#[derive(Debug)]
+pub struct Channel<Req, Resp> {
+    to_dispatch: mpsc::Sender<DispatchRequest<Req, Resp>>,
+    /// Channel to send a cancel message to the dispatcher.
+    cancellation: RequestCancellation,
+    /// The ID to use for the next request to stage.
+    next_request_id: Arc<AtomicU64>,
+    server_addr: SocketAddr,
+}
+
+impl<Req, Resp> Clone for Channel<Req, Resp> {
+    fn clone(&self) -> Self {
+        Self {
+            to_dispatch: self.to_dispatch.clone(),
+            cancellation: self.cancellation.clone(),
+            next_request_id: self.next_request_id.clone(),
+            server_addr: self.server_addr,
+        }
+    }
+}
+
+/// A future returned by [`Channel::send`] that resolves to a server response.
+#[derive(Debug)]
+#[must_use = "futures do nothing unless polled"]
+struct Send<'a, Req, Resp> {
+    fut: MapOkDispatchResponse<
+        MapErrConnectionReset<futures::sink::Send<'a, mpsc::Sender<DispatchRequest<Req, Resp>>>>,
+        Resp,
+    >,
+}
+
+impl<'a, Req, Resp> Send<'a, Req, Resp> {
+    unsafe_pinned!(
+        fut: MapOkDispatchResponse<
+            MapErrConnectionReset<
+                futures::sink::Send<'a, mpsc::Sender<DispatchRequest<Req, Resp>>>,
+            >,
+            Resp,
+        >
+    );
+}
+
+impl<'a, Req, Resp> Future for Send<'a, Req, Resp> {
+    type Output = io::Result<DispatchResponse<Resp>>;
+
+    fn poll(mut self: Pin<&mut Self>, lw: &LocalWaker) -> Poll<Self::Output> {
+        self.fut().poll(lw)
+    }
+}
+
+/// A future returned by [`Channel::call`] that resolves to a server response.
+#[derive(Debug)]
+#[must_use = "futures do nothing unless polled"]
+pub struct Call<'a, Req, Resp> {
+    fut: AndThenIdent<Send<'a, Req, Resp>, DispatchResponse<Resp>>,
+}
+
+impl<'a, Req, Resp> Call<'a, Req, Resp> {
+    unsafe_pinned!(fut: AndThenIdent<Send<'a, Req, Resp>, DispatchResponse<Resp>>);
+}
+
+impl<'a, Req, Resp> Future for Call<'a, Req, Resp> {
+    type Output = io::Result<Resp>;
+
+    fn poll(mut self: Pin<&mut Self>, lw: &LocalWaker) -> Poll<Self::Output> {
+        self.fut().poll(lw)
+    }
+}
+
+impl<Req, Resp> Channel<Req, Resp> {
+    /// Sends a request to the dispatch task to forward to the server, returning a [`Future`] that
+    /// resolves when the request is sent (not when the response is received).
+    fn send<'a>(&'a mut self, mut ctx: context::Context, request: Req) -> Send<'a, Req, Resp> {
+        // Convert the context to the call context.
+        ctx.trace_context.parent_id = Some(ctx.trace_context.span_id);
+        ctx.trace_context.span_id = SpanId::random(&mut rand::thread_rng());
+
+        let timeout = ctx.deadline.as_duration();
+        let deadline = Instant::now() + timeout;
+        trace!(
+            "[{}/{}] Queuing request with deadline {} (timeout {:?}).",
+            ctx.trace_id(),
+            self.server_addr,
+            format_rfc3339(ctx.deadline),
+            timeout,
+        );
+
+        let (response_completion, response) = oneshot::channel();
+        let cancellation = self.cancellation.clone();
+        let request_id = self.next_request_id.fetch_add(1, Ordering::Relaxed);
+        let server_addr = self.server_addr;
+        Send {
+            fut: MapOkDispatchResponse::new(
+                MapErrConnectionReset::new(self.to_dispatch.send(DispatchRequest {
+                    ctx,
+                    request_id,
+                    request,
+                    response_completion,
+                })),
+                DispatchResponse {
+                    response: deadline_compat::Deadline::new(response, deadline),
+                    complete: false,
+                    request_id,
+                    cancellation,
+                    ctx,
+                    server_addr,
+                },
+            ),
+        }
+    }
+
+    /// Sends a request to the dispatch task to forward to the server, returning a [`Future`] that
+    /// resolves to the response.
+    pub fn call<'a>(&'a mut self, context: context::Context, request: Req) -> Call<'a, Req, Resp> {
+        Call {
+            fut: AndThenIdent::new(self.send(context, request)),
+        }
+    }
+}
+
+/// A server response that is completed by request dispatch when the corresponding response
+/// arrives off the wire.
+#[derive(Debug)]
+struct DispatchResponse<Resp> {
+    response: deadline_compat::Deadline<oneshot::Receiver<Response<Resp>>>,
+    ctx: context::Context,
+    complete: bool,
+    cancellation: RequestCancellation,
+    request_id: u64,
+    server_addr: SocketAddr,
+}
+
+impl<Resp> DispatchResponse<Resp> {
+    unsafe_pinned!(server_addr: SocketAddr);
+    unsafe_pinned!(ctx: context::Context);
+}
+
+impl<Resp> Future for DispatchResponse<Resp> {
+    type Output = io::Result<Resp>;
+
+    fn poll(mut self: Pin<&mut Self>, waker: &LocalWaker) -> Poll<io::Result<Resp>> {
+        let resp = ready!(self.response.poll_unpin(waker));
+
+        self.complete = true;
+
+        Poll::Ready(match resp {
+            Ok(resp) => Ok(resp.message?),
+            Err(e) => Err({
+                let trace_id = *self.ctx().trace_id();
+                let server_addr = *self.server_addr();
+
+                if e.is_elapsed() {
+                    io::Error::new(
+                        io::ErrorKind::TimedOut,
+                        "Client dropped expired request.".to_string(),
+                    )
+                } else if e.is_timer() {
+                    let e = e.into_timer().unwrap();
+                    if e.is_at_capacity() {
+                        io::Error::new(
+                            io::ErrorKind::Other,
+                            "Cancelling request because an expiration could not be set \
+                             due to the timer being at capacity."
+                                .to_string(),
+                        )
+                    } else if e.is_shutdown() {
+                        panic!("[{}/{}] Timer was shutdown", trace_id, server_addr)
+                    } else {
+                        panic!(
+                            "[{}/{}] Unrecognized timer error: {}",
+                            trace_id, server_addr, e
+                        )
+                    }
+                } else if e.is_inner() {
+                    // The oneshot is Canceled when the dispatch task ends.
+                    io::Error::from(io::ErrorKind::ConnectionReset)
+                } else {
+                    panic!(
+                        "[{}/{}] Unrecognized deadline error: {}",
+                        trace_id, server_addr, e
+                    )
+                }
+            }),
+        })
+    }
+}
+
+// Cancels the request when dropped, if not already complete.
+impl<Resp> Drop for DispatchResponse<Resp> {
+    fn drop(&mut self) {
+        if !self.complete {
+            // The receiver needs to be closed to handle the edge case that the request has not
+            // yet been received by the dispatch task. It is possible for the cancel message to
+            // arrive before the request itself, in which case the request could get stuck in the
+            // dispatch map forever if the server never responds (e.g. if the server dies while
+            // responding). Even if the server does respond, it will have unnecessarily done work
+            // for a client no longer waiting for a response. To avoid this, the dispatch task
+            // checks if the receiver is closed before inserting the request in the map. By
+            // closing the receiver before sending the cancel message, it is guaranteed that if the
+            // dispatch task misses an early-arriving cancellation message, then it will see the
+            // receiver as closed.
+            self.response.get_mut().close();
+            self.cancellation.cancel(self.request_id);
+        }
+    }
+}
+
+/// Spawns a dispatch task on the default executor that manages the lifecycle of requests initiated
+/// by the returned [`Channel`].
+pub async fn spawn<Req, Resp, C>(
+    config: Config,
+    transport: C,
+    server_addr: SocketAddr,
+) -> io::Result<Channel<Req, Resp>>
+where
+    Req: marker::Send + 'static,
+    Resp: marker::Send + 'static,
+    C: Transport<Item = Response<Resp>, SinkItem = ClientMessage<Req>> + marker::Send + 'static,
+{
+    let (to_dispatch, pending_requests) = mpsc::channel(config.pending_request_buffer);
+    let (cancellation, canceled_requests) = cancellations();
+
+    crate::spawn(
+        RequestDispatch {
+            config,
+            server_addr,
+            canceled_requests,
+            transport: transport.fuse(),
+            in_flight_requests: FnvHashMap::default(),
+            pending_requests: pending_requests.fuse(),
+        }
+        .unwrap_or_else(move |e| error!("[{}] Connection broken: {}", server_addr, e)),
+    )
+    .map_err(|e| {
+        io::Error::new(
+            io::ErrorKind::Other,
+            format!(
+                "Could not spawn client dispatch task. Is shutdown: {}",
+                e.is_shutdown()
+            ),
+        )
+    })?;
+
+    Ok(Channel {
+        to_dispatch,
+        cancellation,
+        server_addr,
+        next_request_id: Arc::new(AtomicU64::new(0)),
+    })
+}
+
+/// Handles the lifecycle of requests, writing requests to the wire, managing cancellations,
+/// and dispatching responses to the appropriate channel.
+struct RequestDispatch<Req, Resp, C> {
+    /// Writes requests to the wire and reads responses off the wire.
+    transport: Fuse<C>,
+    /// Requests waiting to be written to the wire.
+    pending_requests: Fuse<mpsc::Receiver<DispatchRequest<Req, Resp>>>,
+    /// Requests that were dropped.
+    canceled_requests: CanceledRequests,
+    /// Requests already written to the wire that haven't yet received responses.
+    in_flight_requests: FnvHashMap<u64, InFlightData<Resp>>,
+    /// Configures limits to prevent unlimited resource usage.
+    config: Config,
+    /// The address of the server connected to.
+    server_addr: SocketAddr,
+}
+
+impl<Req, Resp, C> RequestDispatch<Req, Resp, C>
+where
+    Req: marker::Send,
+    Resp: marker::Send,
+    C: Transport<Item = Response<Resp>, SinkItem = ClientMessage<Req>>,
+{
+    unsafe_pinned!(server_addr: SocketAddr);
+    unsafe_pinned!(in_flight_requests: FnvHashMap<u64, InFlightData<Resp>>);
+    unsafe_pinned!(canceled_requests: CanceledRequests);
+    unsafe_pinned!(pending_requests: Fuse<mpsc::Receiver<DispatchRequest<Req, Resp>>>);
+    unsafe_pinned!(transport: Fuse<C>);
+
+    fn pump_read(self: &mut Pin<&mut Self>, waker: &LocalWaker) -> Poll<Option<io::Result<()>>> {
+        Poll::Ready(match ready!(self.transport().poll_next(waker)?) {
+            Some(response) => {
+                self.complete(response);
+                Some(Ok(()))
+            }
+            None => {
+                trace!("[{}] read half closed", self.server_addr());
+                None
+            }
+        })
+    }
+
+    fn pump_write(self: &mut Pin<&mut Self>, waker: &LocalWaker) -> Poll<Option<io::Result<()>>> {
+        enum ReceiverStatus {
+            NotReady,
+            Closed,
+        }
+
+        let pending_requests_status = match self.poll_next_request(waker)? {
+            Poll::Ready(Some(dispatch_request)) => {
+                self.write_request(dispatch_request)?;
+                return Poll::Ready(Some(Ok(())));
+            }
+            Poll::Ready(None) => ReceiverStatus::Closed,
+            Poll::Pending => ReceiverStatus::NotReady,
+        };
+
+        let canceled_requests_status = match self.poll_next_cancellation(waker)? {
+            Poll::Ready(Some((context, request_id))) => {
+                self.write_cancel(context, request_id)?;
+                return Poll::Ready(Some(Ok(())));
+            }
+            Poll::Ready(None) => ReceiverStatus::Closed,
+            Poll::Pending => ReceiverStatus::NotReady,
+        };
+
+        match (pending_requests_status, canceled_requests_status) {
+            (ReceiverStatus::Closed, ReceiverStatus::Closed) => {
+                ready!(self.transport().poll_flush(waker)?);
+                Poll::Ready(None)
+            }
+            (ReceiverStatus::NotReady, _) | (_, ReceiverStatus::NotReady) => {
+                // No more messages to process, so flush any messages buffered in the transport.
+                ready!(self.transport().poll_flush(waker)?);
+
+                // Even if we fully-flush, we return Pending, because we have no more requests
+                // or cancellations right now.
+                Poll::Pending
+            }
+        }
+    }
+
+    /// Yields the next pending request, if one is ready to be sent.
+    fn poll_next_request(
+        self: &mut Pin<&mut Self>,
+        waker: &LocalWaker,
+    ) -> Poll<Option<io::Result<DispatchRequest<Req, Resp>>>> {
+        if self.in_flight_requests().len() >= self.config.max_in_flight_requests {
+            info!(
+                "At in-flight request capacity ({}/{}).",
+                self.in_flight_requests().len(),
+                self.config.max_in_flight_requests
+            );
+
+            // No need to schedule a wakeup, because timers and responses are responsible
+            // for clearing out in-flight requests.
+            return Poll::Pending;
+        }
+
+        while let Poll::Pending = self.transport().poll_ready(waker)? {
+            // We can't yield a request-to-be-sent before the transport is capable of buffering it.
+            ready!(self.transport().poll_flush(waker)?);
+        }
+
+        loop {
+            match ready!(self.pending_requests().poll_next_unpin(waker)) {
+                Some(request) => {
+                    if request.response_completion.is_canceled() {
+                        trace!(
+                            "[{}] Request canceled before being sent.",
+                            request.ctx.trace_id()
+                        );
+                        continue;
+                    }
+
+                    return Poll::Ready(Some(Ok(request)));
+                }
+                None => {
+                    trace!("[{}] pending_requests closed", self.server_addr());
+                    return Poll::Ready(None);
+                }
+            }
+        }
+    }
+
+    /// Yields the next pending cancellation, and, if one is ready, cancels the associated request.
+    fn poll_next_cancellation(
+        self: &mut Pin<&mut Self>,
+        waker: &LocalWaker,
+    ) -> Poll<Option<io::Result<(context::Context, u64)>>> {
+        while let Poll::Pending = self.transport().poll_ready(waker)? {
+            ready!(self.transport().poll_flush(waker)?);
+        }
+
+        loop {
+            match ready!(self.canceled_requests().poll_next_unpin(waker)) {
+                Some(request_id) => {
+                    if let Some(in_flight_data) = self.in_flight_requests().remove(&request_id) {
+                        self.in_flight_requests().compact(0.1);
+
+                        debug!(
+                            "[{}/{}] Removed request.",
+                            in_flight_data.ctx.trace_id(),
+                            self.server_addr()
+                        );
+
+                        return Poll::Ready(Some(Ok((in_flight_data.ctx, request_id))));
+                    }
+                }
+                None => {
+                    trace!("[{}] canceled_requests closed.", self.server_addr());
+                    return Poll::Ready(None);
+                }
+            }
+        }
+    }
+
+    fn write_request(
+        self: &mut Pin<&mut Self>,
+        dispatch_request: DispatchRequest<Req, Resp>,
+    ) -> io::Result<()> {
+        let request_id = dispatch_request.request_id;
+        let request = ClientMessage {
+            trace_context: dispatch_request.ctx.trace_context,
+            message: ClientMessageKind::Request(Request {
+                id: request_id,
+                message: dispatch_request.request,
+                deadline: dispatch_request.ctx.deadline,
+            }),
+        };
+        self.transport().start_send(request)?;
+        self.in_flight_requests().insert(
+            request_id,
+            InFlightData {
+                ctx: dispatch_request.ctx,
+                response_completion: dispatch_request.response_completion,
+            },
+        );
+        Ok(())
+    }
+
+    fn write_cancel(
+        self: &mut Pin<&mut Self>,
+        context: context::Context,
+        request_id: u64,
+    ) -> io::Result<()> {
+        let trace_id = *context.trace_id();
+        let cancel = ClientMessage {
+            trace_context: context.trace_context,
+            message: ClientMessageKind::Cancel { request_id },
+        };
+        self.transport().start_send(cancel)?;
+        trace!("[{}/{}] Cancel message sent.", trace_id, self.server_addr());
+        return Ok(());
+    }
+
+    /// Sends a server response to the client task that initiated the associated request.
+    fn complete(self: &mut Pin<&mut Self>, response: Response<Resp>) -> bool {
+        if let Some(in_flight_data) = self.in_flight_requests().remove(&response.request_id) {
+            self.in_flight_requests().compact(0.1);
+
+            trace!(
+                "[{}/{}] Received response.",
+                in_flight_data.ctx.trace_id(),
+                self.server_addr()
+            );
+            let _ = in_flight_data.response_completion.send(response);
+            return true;
+        }
+
+        debug!(
+            "[{}] No in-flight request found for request_id = {}.",
+            self.server_addr(),
+            response.request_id
+        );
+
+        // If the response completion was absent, then the request was already canceled.
+        false
+    }
+}
+
+impl<Req, Resp, C> Future for RequestDispatch<Req, Resp, C>
+where
+    Req: marker::Send,
+    Resp: marker::Send,
+    C: Transport<Item = Response<Resp>, SinkItem = ClientMessage<Req>>,
+{
+    type Output = io::Result<()>;
+
+    fn poll(mut self: Pin<&mut Self>, waker: &LocalWaker) -> Poll<io::Result<()>> {
+        trace!("[{}] RequestDispatch::poll", self.server_addr());
+        loop {
+            match (self.pump_read(waker)?, self.pump_write(waker)?) {
+                (read, write @ Poll::Ready(None)) => {
+                    if self.in_flight_requests().is_empty() {
+                        info!(
+                            "[{}] Shutdown: write half closed, and no requests in flight.",
+                            self.server_addr()
+                        );
+                        return Poll::Ready(Ok(()));
+                    }
+                    match read {
+                        Poll::Ready(Some(())) => continue,
+                        _ => {
+                            trace!(
+                                "[{}] read: {:?}, write: {:?}, (not ready)",
+                                self.server_addr(),
+                                read,
+                                write,
+                            );
+                            return Poll::Pending;
+                        }
+                    }
+                }
+                (read @ Poll::Ready(Some(())), write) | (read, write @ Poll::Ready(Some(()))) => {
+                    trace!(
+                        "[{}] read: {:?}, write: {:?}",
+                        self.server_addr(),
+                        read,
+                        write,
+                    )
+                }
+                (read, write) => {
+                    trace!(
+                        "[{}] read: {:?}, write: {:?} (not ready)",
+                        self.server_addr(),
+                        read,
+                        write,
+                    );
+                    return Poll::Pending;
+                }
+            }
+        }
+    }
+}
+
+/// A server-bound request sent from a [`Channel`] to request dispatch, which will then manage
+/// the lifecycle of the request.
+#[derive(Debug)]
+struct DispatchRequest<Req, Resp> {
+    ctx: context::Context,
+    request_id: u64,
+    request: Req,
+    response_completion: oneshot::Sender<Response<Resp>>,
+}
+
+struct InFlightData<Resp> {
+    ctx: context::Context,
+    response_completion: oneshot::Sender<Response<Resp>>,
+}
+
+/// Sends request cancellation signals.
+#[derive(Debug, Clone)]
+struct RequestCancellation(mpsc::UnboundedSender<u64>);
+
+/// A stream of IDs of requests that have been canceled.
+#[derive(Debug)]
+struct CanceledRequests(mpsc::UnboundedReceiver<u64>);
+
+/// Returns a channel to send request cancellation messages.
+fn cancellations() -> (RequestCancellation, CanceledRequests) {
+    // Unbounded because messages are sent in the drop fn. This is fine, because it's still
+    // bounded by the number of in-flight requests. Additionally, each request has a clone
+    // of the sender, so the bounded channel would have the same behavior,
+    // since it guarantees a slot.
+    let (tx, rx) = mpsc::unbounded();
+    (RequestCancellation(tx), CanceledRequests(rx))
+}
+
+impl RequestCancellation {
+    /// Cancels the request with ID `request_id`.
+    fn cancel(&mut self, request_id: u64) {
+        let _ = self.0.unbounded_send(request_id);
+    }
+}
+
+impl Stream for CanceledRequests {
+    type Item = u64;
+
+    fn poll_next(mut self: Pin<&mut Self>, waker: &LocalWaker) -> Poll<Option<u64>> {
+        self.0.poll_next_unpin(waker)
+    }
+}
+
+#[derive(Debug)]
+#[must_use = "futures do nothing unless polled"]
+struct MapErrConnectionReset<Fut> {
+    future: Fut,
+    finished: Option<()>,
+}
+
+impl<Fut> MapErrConnectionReset<Fut> {
+    unsafe_pinned!(future: Fut);
+    unsafe_unpinned!(finished: Option<()>);
+
+    fn new(future: Fut) -> MapErrConnectionReset<Fut> {
+        MapErrConnectionReset {
+            future,
+            finished: Some(()),
+        }
+    }
+}
+
+impl<Fut: Unpin> Unpin for MapErrConnectionReset<Fut> {}
+
+impl<Fut> Future for MapErrConnectionReset<Fut>
+where
+    Fut: TryFuture,
+{
+    type Output = io::Result<Fut::Ok>;
+
+    fn poll(mut self: Pin<&mut Self>, lw: &LocalWaker) -> Poll<Self::Output> {
+        match self.future().try_poll(lw) {
+            Poll::Pending => Poll::Pending,
+            Poll::Ready(result) => {
+                self.finished().take().expect(
+                    "MapErrConnectionReset must not be polled after it returned `Poll::Ready`",
+                );
+                Poll::Ready(result.map_err(|_| io::Error::from(io::ErrorKind::ConnectionReset)))
+            }
+        }
+    }
+}
+
+#[derive(Debug)]
+#[must_use = "futures do nothing unless polled"]
+struct MapOkDispatchResponse<Fut, Resp> {
+    future: Fut,
+    response: Option<DispatchResponse<Resp>>,
+}
+
+impl<Fut, Resp> MapOkDispatchResponse<Fut, Resp> {
+    unsafe_pinned!(future: Fut);
+    unsafe_unpinned!(response: Option<DispatchResponse<Resp>>);
+
+    fn new(future: Fut, response: DispatchResponse<Resp>) -> MapOkDispatchResponse<Fut, Resp> {
+        MapOkDispatchResponse {
+            future,
+            response: Some(response),
+        }
+    }
+}
+
+impl<Fut: Unpin, Resp> Unpin for MapOkDispatchResponse<Fut, Resp> {}
+
+impl<Fut, Resp> Future for MapOkDispatchResponse<Fut, Resp>
+where
+    Fut: TryFuture,
+{
+    type Output = Result<DispatchResponse<Resp>, Fut::Error>;
+
+    fn poll(mut self: Pin<&mut Self>, lw: &LocalWaker) -> Poll<Self::Output> {
+        match self.future().try_poll(lw) {
+            Poll::Pending => Poll::Pending,
+            Poll::Ready(result) => {
+                let response = self
+                    .response()
+                    .take()
+                    .expect("MapOk must not be polled after it returned `Poll::Ready`");
+                Poll::Ready(result.map(|_| response))
+            }
+        }
+    }
+}
+
+#[derive(Debug)]
+#[must_use = "futures do nothing unless polled"]
+struct AndThenIdent<Fut1, Fut2> {
+    try_chain: TryChain<Fut1, Fut2>,
+}
+
+impl<Fut1, Fut2> AndThenIdent<Fut1, Fut2>
+where
+    Fut1: TryFuture<Ok = Fut2>,
+    Fut2: TryFuture,
+{
+    unsafe_pinned!(try_chain: TryChain<Fut1, Fut2>);
+
+    /// Creates a new `Then`.
+    fn new(future: Fut1) -> AndThenIdent<Fut1, Fut2> {
+        AndThenIdent {
+            try_chain: TryChain::new(future),
+        }
+    }
+}
+
+impl<Fut1, Fut2> Future for AndThenIdent<Fut1, Fut2>
+where
+    Fut1: TryFuture<Ok = Fut2>,
+    Fut2: TryFuture<Error = Fut1::Error>,
+{
+    type Output = Result<Fut2::Ok, Fut2::Error>;
+
+    fn poll(mut self: Pin<&mut Self>, lw: &LocalWaker) -> Poll<Self::Output> {
+        self.try_chain().poll(lw, |result| match result {
+            Ok(ok) => TryChainAction::Future(ok),
+            Err(err) => TryChainAction::Output(Err(err)),
+        })
+    }
+}
+
+#[must_use = "futures do nothing unless polled"]
+#[derive(Debug)]
+enum TryChain<Fut1, Fut2> {
+    First(Fut1),
+    Second(Fut2),
+    Empty,
+}
+
+enum TryChainAction<Fut2>
+where
+    Fut2: TryFuture,
+{
+    Future(Fut2),
+    Output(Result<Fut2::Ok, Fut2::Error>),
+}
+
+impl<Fut1, Fut2> TryChain<Fut1, Fut2>
+where
+    Fut1: TryFuture<Ok = Fut2>,
+    Fut2: TryFuture,
+{
+    fn new(fut1: Fut1) -> TryChain<Fut1, Fut2> {
+        TryChain::First(fut1)
+    }
+
+    fn poll<F>(self: Pin<&mut Self>, lw: &LocalWaker, f: F) -> Poll<Result<Fut2::Ok, Fut2::Error>>
+    where
+        F: FnOnce(Result<Fut1::Ok, Fut1::Error>) -> TryChainAction<Fut2>,
+    {
+        let mut f = Some(f);
+
+        // Safe to call `get_mut_unchecked` because we won't move the futures.
+        let this = unsafe { Pin::get_mut_unchecked(self) };
+
+        loop {
+            let output = match this {
+                TryChain::First(fut1) => {
+                    // Poll the first future
+                    match unsafe { Pin::new_unchecked(fut1) }.try_poll(lw) {
+                        Poll::Pending => return Poll::Pending,
+                        Poll::Ready(output) => output,
+                    }
+                }
+                TryChain::Second(fut2) => {
+                    // Poll the second future
+                    return unsafe { Pin::new_unchecked(fut2) }.try_poll(lw);
+                }
+                TryChain::Empty => {
+                    panic!("future must not be polled after it returned `Poll::Ready`");
+                }
+            };
+
+            *this = TryChain::Empty; // Drop fut1
+            let f = f.take().unwrap();
+            match f(output) {
+                TryChainAction::Future(fut2) => *this = TryChain::Second(fut2),
+                TryChainAction::Output(output) => return Poll::Ready(output),
+            }
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::{CanceledRequests, Channel, RequestCancellation, RequestDispatch};
+    use crate::{
+        client::Config,
+        context,
+        transport::{self, channel::UnboundedChannel},
+        ClientMessage, Response,
+    };
+    use fnv::FnvHashMap;
+    use futures::{channel::mpsc, prelude::*, Poll};
+    use futures_test::task::noop_local_waker_ref;
+    use std::{
+        marker,
+        net::{IpAddr, Ipv4Addr, SocketAddr},
+        pin::Pin,
+        sync::atomic::AtomicU64,
+        sync::Arc,
+    };
+
+    #[test]
+    fn stage_request() {
+        let (mut dispatch, mut channel, _server_channel) = set_up();
+
+        // Test that a request future dropped before it's processed by dispatch will cause the request
+        // to not be added to the in-flight request map.
+        let _resp = tokio::runtime::current_thread::block_on_all(
+            channel
+                .send(context::current(), "hi".to_string())
+                .boxed()
+                .compat(),
+        );
+
+        let mut dispatch = Pin::new(&mut dispatch);
+        let waker = &noop_local_waker_ref();
+
+        let req = dispatch.poll_next_request(waker).ready();
+        assert!(req.is_some());
+
+        let req = req.unwrap();
+        assert_eq!(req.request_id, 0);
+        assert_eq!(req.request, "hi".to_string());
+    }
+
+    #[test]
+    fn stage_request_response_future_dropped() {
+        let (mut dispatch, mut channel, _server_channel) = set_up();
+
+        // Test that a request future dropped before it's processed by dispatch will cause the request
+        // to not be added to the in-flight request map.
+        let resp = tokio::runtime::current_thread::block_on_all(
+            channel
+                .send(context::current(), "hi".into())
+                .boxed()
+                .compat(),
+        )
+        .unwrap();
+        drop(resp);
+        drop(channel);
+
+        let mut dispatch = Pin::new(&mut dispatch);
+        let waker = &noop_local_waker_ref();
+
+        dispatch.poll_next_cancellation(waker).unwrap();
+        assert!(dispatch.poll_next_request(waker).ready().is_none());
+    }
+
+    #[test]
+    fn stage_request_response_future_closed() {
+        let (mut dispatch, mut channel, _server_channel) = set_up();
+
+        // Test that a request future that's closed its receiver but not yet canceled its request --
+        // i.e. still in `drop fn` -- will cause the request to not be added to the in-flight request
+        // map.
+        let resp = tokio::runtime::current_thread::block_on_all(
+            channel
+                .send(context::current(), "hi".into())
+                .boxed()
+                .compat(),
+        )
+        .unwrap();
+        drop(resp);
+        drop(channel);
+
+        let mut dispatch = Pin::new(&mut dispatch);
+        let waker = &noop_local_waker_ref();
+        assert!(dispatch.poll_next_request(waker).ready().is_none());
+    }
+
+    fn set_up() -> (
+        RequestDispatch<String, String, UnboundedChannel<Response<String>, ClientMessage<String>>>,
+        Channel<String, String>,
+        UnboundedChannel<ClientMessage<String>, Response<String>>,
+    ) {
+        let _ = env_logger::try_init();
+
+        let (to_dispatch, pending_requests) = mpsc::channel(1);
+        let (cancel_tx, canceled_requests) = mpsc::unbounded();
+        let (client_channel, server_channel) = transport::channel::unbounded();
+
+        let dispatch = RequestDispatch::<String, String, _> {
+            transport: client_channel.fuse(),
+            pending_requests: pending_requests.fuse(),
+            canceled_requests: CanceledRequests(canceled_requests),
+            in_flight_requests: FnvHashMap::default(),
+            config: Config::default(),
+            server_addr: SocketAddr::new(IpAddr::V4(Ipv4Addr::LOCALHOST), 0),
+        };
+
+        let cancellation = RequestCancellation(cancel_tx);
+        let channel = Channel {
+            to_dispatch,
+            cancellation,
+            next_request_id: Arc::new(AtomicU64::new(0)),
+            server_addr: SocketAddr::new(Ipv4Addr::UNSPECIFIED.into(), 0),
+        };
+
+        (dispatch, channel, server_channel)
+    }
+
+    trait PollTest {
+        type T;
+        fn unwrap(self) -> Poll<Self::T>;
+        fn ready(self) -> Self::T;
+    }
+
+    impl<T, E> PollTest for Poll<Option<Result<T, E>>>
+    where
+        E: ::std::fmt::Display + marker::Send + 'static,
+    {
+        type T = Option<T>;
+
+        fn unwrap(self) -> Poll<Option<T>> {
+            match self {
+                Poll::Ready(Some(Ok(t))) => Poll::Ready(Some(t)),
+                Poll::Ready(None) => Poll::Ready(None),
+                Poll::Ready(Some(Err(e))) => panic!(e.to_string()),
+                Poll::Pending => Poll::Pending,
+            }
+        }
+
+        fn ready(self) -> Option<T> {
+            match self {
+                Poll::Ready(Some(Ok(t))) => Some(t),
+                Poll::Ready(None) => None,
+                Poll::Ready(Some(Err(e))) => panic!(e.to_string()),
+                Poll::Pending => panic!("Pending"),
+            }
+        }
+    }
+
+}

rpc/src/client/mod.rs

@@ -0,0 +1,151 @@
+// Copyright 2018 Google LLC
+//
+// Use of this source code is governed by an MIT-style
+// license that can be found in the LICENSE file or at
+// https://opensource.org/licenses/MIT.
+
+//! Provides a client that connects to a server and sends multiplexed requests.
+
+use crate::{context, ClientMessage, Response, Transport};
+use futures::prelude::*;
+use log::warn;
+use std::{
+    io,
+    net::{Ipv4Addr, SocketAddr},
+};
+
+/// Provides a [`Client`] backed by a transport.
+pub mod channel;
+pub use self::channel::Channel;
+
+/// Sends multiplexed requests to, and receives responses from, a server.
+pub trait Client<'a, Req> {
+    /// The response type.
+    type Response;
+
+    /// The future response.
+    type Future: Future<Output = io::Result<Self::Response>> + 'a;
+
+    /// Initiates a request, sending it to the dispatch task.
+    ///
+    /// Returns a [`Future`] that resolves to this client and the future response
+    /// once the request is successfully enqueued.
+    ///
+    /// [`Future`]: futures::Future
+    fn call(&'a mut self, ctx: context::Context, request: Req) -> Self::Future;
+
+    /// Returns a Client that applies a post-processing function to the returned response.
+    fn map_response<F, R>(self, f: F) -> MapResponse<Self, F>
+    where
+        F: FnMut(Self::Response) -> R,
+        Self: Sized,
+    {
+        MapResponse { inner: self, f }
+    }
+
+    /// Returns a Client that applies a pre-processing function to the request.
+    fn with_request<F, Req2>(self, f: F) -> WithRequest<Self, F>
+    where
+        F: FnMut(Req2) -> Req,
+        Self: Sized,
+    {
+        WithRequest { inner: self, f }
+    }
+}
+
+/// A Client that applies a function to the returned response.
+#[derive(Clone, Debug)]
+pub struct MapResponse<C, F> {
+    inner: C,
+    f: F,
+}
+
+impl<'a, C, F, Req, Resp, Resp2> Client<'a, Req> for MapResponse<C, F>
+where
+    C: Client<'a, Req, Response = Resp>,
+    F: FnMut(Resp) -> Resp2 + 'a,
+{
+    type Response = Resp2;
+    type Future = futures::future::MapOk<<C as Client<'a, Req>>::Future, &'a mut F>;
+
+    fn call(&'a mut self, ctx: context::Context, request: Req) -> Self::Future {
+        self.inner.call(ctx, request).map_ok(&mut self.f)
+    }
+}
+
+/// A Client that applies a pre-processing function to the request.
+#[derive(Clone, Debug)]
+pub struct WithRequest<C, F> {
+    inner: C,
+    f: F,
+}
+
+impl<'a, C, F, Req, Req2, Resp> Client<'a, Req2> for WithRequest<C, F>
+where
+    C: Client<'a, Req, Response = Resp>,
+    F: FnMut(Req2) -> Req,
+{
+    type Response = Resp;
+    type Future = <C as Client<'a, Req>>::Future;
+
+    fn call(&'a mut self, ctx: context::Context, request: Req2) -> Self::Future {
+        self.inner.call(ctx, (self.f)(request))
+    }
+}
+
+impl<'a, Req, Resp> Client<'a, Req> for Channel<Req, Resp>
+where
+    Req: 'a,
+    Resp: 'a,
+{
+    type Response = Resp;
+    type Future = channel::Call<'a, Req, Resp>;
+
+    fn call(&'a mut self, ctx: context::Context, request: Req) -> channel::Call<'a, Req, Resp> {
+        self.call(ctx, request)
+    }
+}
+
+/// Settings that control the behavior of the client.
+#[non_exhaustive]
+#[derive(Clone, Debug)]
+pub struct Config {
+    /// The number of requests that can be in flight at once.
+    /// `max_in_flight_requests` controls the size of the map used by the client
+    /// for storing pending requests.
+    pub max_in_flight_requests: usize,
+    /// The number of requests that can be buffered client-side before being sent.
+    /// `pending_requests_buffer` controls the size of the channel clients use
+    /// to communicate with the request dispatch task.
+    pub pending_request_buffer: usize,
+}
+
+impl Default for Config {
+    fn default() -> Self {
+        Config {
+            max_in_flight_requests: 1_000,
+            pending_request_buffer: 100,
+        }
+    }
+}
+
+/// Creates a new Client by wrapping a [`Transport`] and spawning a dispatch task
+/// that manages the lifecycle of requests.
+///
+/// Must only be called from on an executor.
+pub async fn new<Req, Resp, T>(config: Config, transport: T) -> io::Result<Channel<Req, Resp>>
+where
+    Req: Send + 'static,
+    Resp: Send + 'static,
+    T: Transport<Item = Response<Resp>, SinkItem = ClientMessage<Req>> + Send + 'static,
+{
+    let server_addr = transport.peer_addr().unwrap_or_else(|e| {
+        warn!(
+            "Setting peer to unspecified because peer could not be determined: {}",
+            e
+        );
+        SocketAddr::new(Ipv4Addr::UNSPECIFIED.into(), 0)
+    });
+
+    Ok(await!(channel::spawn(config, transport, server_addr))?)
+}

rpc/src/context.rs

@@ -0,0 +1,45 @@
+// Copyright 2018 Google LLC
+//
+// Use of this source code is governed by an MIT-style
+// license that can be found in the LICENSE file or at
+// https://opensource.org/licenses/MIT.
+
+//! Provides a request context that carries a deadline and trace context. This context is sent from
+//! client to server and is used by the server to enforce response deadlines.
+
+use std::time::{Duration, SystemTime};
+use trace::{self, TraceId};
+
+/// A request context that carries request-scoped information like deadlines and trace information.
+/// It is sent from client to server and is used by the server to enforce response deadlines.
+///
+/// The context should not be stored directly in a server implementation, because the context will
+/// be different for each request in scope.
+#[derive(Clone, Copy, Debug)]
+#[non_exhaustive]
+pub struct Context {
+    /// When the client expects the request to be complete by. The server should cancel the request
+    /// if it is not complete by this time.
+    pub deadline: SystemTime,
+    /// Uniquely identifies requests originating from the same source.
+    /// When a service handles a request by making requests itself, those requests should
+    /// include the same `trace_id` as that included on the original request. This way,
+    /// users can trace related actions across a distributed system.
+    pub trace_context: trace::Context,
+}
+
+/// Returns the context for the current request, or a default Context if no request is active.
+// TODO: populate Context with request-scoped data, with default fallbacks.
+pub fn current() -> Context {
+    Context {
+        deadline: SystemTime::now() + Duration::from_secs(10),
+        trace_context: trace::Context::new_root(),
+    }
+}
+
+impl Context {
+    /// Returns the ID of the request-scoped trace.
+    pub fn trace_id(&self) -> &TraceId {
+        &self.trace_context.trace_id
+    }
+}

rpc/src/lib.rs

@@ -0,0 +1,209 @@
+// Copyright 2018 Google LLC
+//
+// Use of this source code is governed by an MIT-style
+// license that can be found in the LICENSE file or at
+// https://opensource.org/licenses/MIT.
+
+#![feature(
+    non_exhaustive,
+    integer_atomics,
+    try_trait,
+    futures_api,
+    pin,
+    arbitrary_self_types,
+    await_macro,
+    async_await,
+)]
+#![deny(missing_docs, missing_debug_implementations)]
+
+//! An RPC framework providing client and server.
+//!
+//! Features:
+//! * RPC deadlines, both client- and server-side.
+//! * Cascading cancellation (works with multiple hops).
+//! * Configurable limits
+//!    * In-flight requests, both client and server-side.
+//!        * Server-side limit is per-connection.
+//!        * When the server reaches the in-flight request maximum, it returns a throttled error
+//!          to the client.
+//!        * When the client reaches the in-flight request max, messages are buffered up to a
+//!          configurable maximum, beyond which the requests are back-pressured.
+//!    * Server connections.
+//!        * Total and per-IP limits.
+//!        * When an incoming connection is accepted, if already at maximum, the connection is
+//!          dropped.
+//! * Transport agnostic.
+
+pub mod client;
+pub mod context;
+pub mod server;
+pub mod transport;
+pub(crate) mod util;
+
+pub use crate::{client::Client, server::Server, transport::Transport};
+
+use futures::{
+    task::{Spawn, SpawnError, SpawnExt},
+    Future,
+};
+use std::{cell::RefCell, io, sync::Once, time::SystemTime};
+
+/// A message from a client to a server.
+#[derive(Debug)]
+#[cfg_attr(
+    feature = "serde1",
+    derive(serde::Serialize, serde::Deserialize)
+)]
+#[non_exhaustive]
+pub struct ClientMessage<T> {
+    /// The trace context associates the message with a specific chain of causally-related actions,
+    /// possibly orchestrated across many distributed systems.
+    pub trace_context: trace::Context,
+    /// The message payload.
+    pub message: ClientMessageKind<T>,
+}
+
+/// Different messages that can be sent from a client to a server.
+#[derive(Debug)]
+#[cfg_attr(
+    feature = "serde1",
+    derive(serde::Serialize, serde::Deserialize)
+)]
+#[non_exhaustive]
+pub enum ClientMessageKind<T> {
+    /// A request initiated by a user. The server responds to a request by invoking a
+    /// service-provided request handler.  The handler completes with a [`response`](Response), which
+    /// the server sends back to the client.
+    Request(Request<T>),
+    /// A command to cancel an in-flight request, automatically sent by the client when a response
+    /// future is dropped.
+    ///
+    /// When received, the server will immediately cancel the main task (top-level future) of the
+    /// request handler for the associated request. Any tasks spawned by the request handler will
+    /// not be canceled, because the framework layer does not
+    /// know about them.
+    Cancel {
+        /// The ID of the request to cancel.
+        request_id: u64,
+    },
+}
+
+/// A request from a client to a server.
+#[derive(Debug)]
+#[cfg_attr(
+    feature = "serde1",
+    derive(serde::Serialize, serde::Deserialize)
+)]
+#[non_exhaustive]
+pub struct Request<T> {
+    /// Uniquely identifies the request across all requests sent over a single channel.
+    pub id: u64,
+    /// The request body.
+    pub message: T,
+    /// When the client expects the request to be complete by. The server will cancel the request
+    /// if it is not complete by this time.
+    #[cfg_attr(
+        feature = "serde1",
+        serde(serialize_with = "util::serde::serialize_epoch_secs")
+    )]
+    #[cfg_attr(
+        feature = "serde1",
+        serde(deserialize_with = "util::serde::deserialize_epoch_secs")
+    )]
+    pub deadline: SystemTime,
+}
+
+/// A response from a server to a client.
+#[derive(Debug, PartialEq, Eq)]
+#[cfg_attr(
+    feature = "serde1",
+    derive(serde::Serialize, serde::Deserialize)
+)]
+#[non_exhaustive]
+pub struct Response<T> {
+    /// The ID of the request being responded to.
+    pub request_id: u64,
+    /// The response body, or an error if the request failed.
+    pub message: Result<T, ServerError>,
+}
+
+/// An error response from a server to a client.
+#[derive(Debug, PartialEq, Eq)]
+#[cfg_attr(
+    feature = "serde1",
+    derive(serde::Serialize, serde::Deserialize)
+)]
+#[non_exhaustive]
+pub struct ServerError {
+    #[cfg_attr(
+        feature = "serde1",
+        serde(serialize_with = "util::serde::serialize_io_error_kind_as_u32")
+    )]
+    #[cfg_attr(
+        feature = "serde1",
+        serde(deserialize_with = "util::serde::deserialize_io_error_kind_from_u32")
+    )]
+    /// The type of error that occurred to fail the request.
+    pub kind: io::ErrorKind,
+    /// A message describing more detail about the error that occurred.
+    pub detail: Option<String>,
+}
+
+impl From<ServerError> for io::Error {
+    fn from(e: ServerError) -> io::Error {
+        io::Error::new(e.kind, e.detail.unwrap_or_default())
+    }
+}
+
+impl<T> Request<T> {
+    /// Returns the deadline for this request.
+    pub fn deadline(&self) -> &SystemTime {
+        &self.deadline
+    }
+}
+
+static INIT: Once = Once::new();
+static mut SEED_SPAWN: Option<Box<dyn CloneSpawn>> = None;
+thread_local! {
+    static SPAWN: RefCell<Box<dyn CloneSpawn>> = {
+        unsafe {
+            // INIT must always be called before accessing SPAWN.
+            // Otherwise, accessing SPAWN can trigger undefined behavior due to race conditions.
+            INIT.call_once(|| {});
+            RefCell::new(SEED_SPAWN.clone().expect("init() must be called."))
+        }
+    };
+}
+
+/// Initializes the RPC library with a mechanism to spawn futures on the user's runtime.
+/// Client stubs and servers both use the initialized spawn.
+///
+/// Init only has an effect the first time it is called. If called previously, successive calls to
+/// init are noops.
+pub fn init(spawn: impl Spawn + Clone + 'static) {
+    unsafe {
+        INIT.call_once(|| {
+            SEED_SPAWN = Some(Box::new(spawn));
+        });
+    }
+}
+
+pub(crate) fn spawn(future: impl Future<Output = ()> + Send + 'static) -> Result<(), SpawnError> {
+    SPAWN.with(|spawn| spawn.borrow_mut().spawn(future))
+}
+
+trait CloneSpawn: Spawn {
+    fn box_clone(&self) -> Box<dyn CloneSpawn>;
+}
+
+impl Clone for Box<dyn CloneSpawn> {
+    fn clone(&self) -> Self {
+        self.box_clone()
+    }
+}
+
+impl<S: Spawn + Clone + 'static> CloneSpawn for S {
+    fn box_clone(&self) -> Box<dyn CloneSpawn> {
+        Box::new(self.clone())
+    }
+}

rpc/src/server/filter.rs

@@ -0,0 +1,260 @@
+// Copyright 2018 Google LLC
+//
+// Use of this source code is governed by an MIT-style
+// license that can be found in the LICENSE file or at
+// https://opensource.org/licenses/MIT.
+
+use crate::{
+    server::{Channel, Config},
+    util::Compact,
+    ClientMessage, Response, Transport,
+};
+use fnv::FnvHashMap;
+use futures::{
+    channel::mpsc,
+    prelude::*,
+    ready,
+    stream::Fuse,
+    task::{LocalWaker, Poll},
+};
+use log::{debug, error, info, trace, warn};
+use pin_utils::unsafe_pinned;
+use std::{
+    collections::hash_map::Entry,
+    io,
+    marker::PhantomData,
+    net::{IpAddr, SocketAddr},
+    ops::Try,
+    option::NoneError,
+    pin::Pin,
+};
+
+/// Drops connections under configurable conditions:
+///
+/// 1. If the max number of connections is reached.
+/// 2. If the max number of connections for a single IP is reached.
+#[derive(Debug)]
+pub struct ConnectionFilter<S, Req, Resp> {
+    listener: Fuse<S>,
+    closed_connections: mpsc::UnboundedSender<SocketAddr>,
+    closed_connections_rx: mpsc::UnboundedReceiver<SocketAddr>,
+    config: Config,
+    connections_per_ip: FnvHashMap<IpAddr, usize>,
+    open_connections: usize,
+    ghost: PhantomData<(Req, Resp)>,
+}
+
+enum NewConnection<Req, Resp, C> {
+    Filtered,
+    Accepted(Channel<Req, Resp, C>),
+}
+
+impl<Req, Resp, C> Try for NewConnection<Req, Resp, C> {
+    type Ok = Channel<Req, Resp, C>;
+    type Error = NoneError;
+
+    fn into_result(self) -> Result<Channel<Req, Resp, C>, NoneError> {
+        match self {
+            NewConnection::Filtered => Err(NoneError),
+            NewConnection::Accepted(channel) => Ok(channel),
+        }
+    }
+
+    fn from_error(_: NoneError) -> Self {
+        NewConnection::Filtered
+    }
+
+    fn from_ok(channel: Channel<Req, Resp, C>) -> Self {
+        NewConnection::Accepted(channel)
+    }
+}
+
+impl<S, Req, Resp> ConnectionFilter<S, Req, Resp> {
+    unsafe_pinned!(open_connections: usize);
+    unsafe_pinned!(config: Config);
+    unsafe_pinned!(connections_per_ip: FnvHashMap<IpAddr, usize>);
+    unsafe_pinned!(closed_connections_rx: mpsc::UnboundedReceiver<SocketAddr>);
+    unsafe_pinned!(listener: Fuse<S>);
+
+    /// Sheds new connections to stay under configured limits.
+    pub fn filter<C>(listener: S, config: Config) -> Self
+    where
+        S: Stream<Item = Result<C, io::Error>>,
+        C: Transport<Item = ClientMessage<Req>, SinkItem = Response<Resp>> + Send,
+    {
+        let (closed_connections, closed_connections_rx) = mpsc::unbounded();
+
+        ConnectionFilter {
+            listener: listener.fuse(),
+            closed_connections,
+            closed_connections_rx,
+            config,
+            connections_per_ip: FnvHashMap::default(),
+            open_connections: 0,
+            ghost: PhantomData,
+        }
+    }
+
+    fn handle_new_connection<C>(self: &mut Pin<&mut Self>, stream: C) -> NewConnection<Req, Resp, C>
+    where
+        C: Transport<Item = ClientMessage<Req>, SinkItem = Response<Resp>> + Send,
+    {
+        let peer = match stream.peer_addr() {
+            Ok(peer) => peer,
+            Err(e) => {
+                warn!("Could not get peer_addr of new connection: {}", e);
+                return NewConnection::Filtered;
+            }
+        };
+
+        let open_connections = *self.open_connections();
+        if open_connections >= self.config().max_connections {
+            warn!(
+                "[{}] Shedding connection because the maximum open connections \
+                 limit is reached ({}/{}).",
+                peer,
+                open_connections,
+                self.config().max_connections
+            );
+            return NewConnection::Filtered;
+        }
+
+        let config = self.config.clone();
+        let open_connections_for_ip = self.increment_connections_for_ip(&peer)?;
+        *self.open_connections() += 1;
+
+        debug!(
+            "[{}] Opening channel ({}/{} connections for IP, {} total).",
+            peer,
+            open_connections_for_ip,
+            config.max_connections_per_ip,
+            self.open_connections(),
+        );
+
+        NewConnection::Accepted(Channel {
+            client_addr: peer,
+            closed_connections: self.closed_connections.clone(),
+            transport: stream.fuse(),
+            config,
+            ghost: PhantomData,
+        })
+    }
+
+    fn handle_closed_connection(self: &mut Pin<&mut Self>, addr: &SocketAddr) {
+        *self.open_connections() -= 1;
+        debug!(
+            "[{}] Closing channel. {} open connections remaining.",
+            addr, self.open_connections
+        );
+        self.decrement_connections_for_ip(&addr);
+        self.connections_per_ip().compact(0.1);
+    }
+
+    fn increment_connections_for_ip(self: &mut Pin<&mut Self>, peer: &SocketAddr) -> Option<usize> {
+        let max_connections_per_ip = self.config().max_connections_per_ip;
+        let mut occupied;
+        let mut connections_per_ip = self.connections_per_ip();
+        let occupied = match connections_per_ip.entry(peer.ip()) {
+            Entry::Vacant(vacant) => vacant.insert(0),
+            Entry::Occupied(o) => {
+                if *o.get() < max_connections_per_ip {
+                    // Store the reference outside the block to extend the lifetime.
+                    occupied = o;
+                    occupied.get_mut()
+                } else {
+                    info!(
+                        "[{}] Opened max connections from IP ({}/{}).",
+                        peer,
+                        o.get(),
+                        max_connections_per_ip
+                    );
+                    return None;
+                }
+            }
+        };
+        *occupied += 1;
+        Some(*occupied)
+    }
+
+    fn decrement_connections_for_ip(self: &mut Pin<&mut Self>, addr: &SocketAddr) {
+        let should_compact = match self.connections_per_ip().entry(addr.ip()) {
+            Entry::Vacant(_) => {
+                error!("[{}] Got vacant entry when closing connection.", addr);
+                return;
+            }
+            Entry::Occupied(mut occupied) => {
+                *occupied.get_mut() -= 1;
+                if *occupied.get() == 0 {
+                    occupied.remove();
+                    true
+                } else {
+                    false
+                }
+            }
+        };
+        if should_compact {
+            self.connections_per_ip().compact(0.1);
+        }
+    }
+
+    fn poll_listener<C>(
+        self: &mut Pin<&mut Self>,
+        cx: &LocalWaker,
+    ) -> Poll<Option<io::Result<NewConnection<Req, Resp, C>>>>
+    where
+        S: Stream<Item = Result<C, io::Error>>,
+        C: Transport<Item = ClientMessage<Req>, SinkItem = Response<Resp>> + Send,
+    {
+        match ready!(self.listener().poll_next_unpin(cx)?) {
+            Some(codec) => Poll::Ready(Some(Ok(self.handle_new_connection(codec)))),
+            None => Poll::Ready(None),
+        }
+    }
+
+    fn poll_closed_connections(self: &mut Pin<&mut Self>, cx: &LocalWaker) -> Poll<io::Result<()>> {
+        match ready!(self.closed_connections_rx().poll_next_unpin(cx)) {
+            Some(addr) => {
+                self.handle_closed_connection(&addr);
+                Poll::Ready(Ok(()))
+            }
+            None => unreachable!("Holding a copy of closed_connections and didn't close it."),
+        }
+    }
+}
+
+impl<S, Req, Resp, T> Stream for ConnectionFilter<S, Req, Resp>
+where
+    S: Stream<Item = Result<T, io::Error>>,
+    T: Transport<Item = ClientMessage<Req>, SinkItem = Response<Resp>> + Send,
+{
+    type Item = io::Result<Channel<Req, Resp, T>>;
+
+    fn poll_next(
+        mut self: Pin<&mut Self>,
+        cx: &LocalWaker,
+    ) -> Poll<Option<io::Result<Channel<Req, Resp, T>>>> {
+        loop {
+            match (self.poll_listener(cx)?, self.poll_closed_connections(cx)?) {
+                (Poll::Ready(Some(NewConnection::Accepted(channel))), _) => {
+                    return Poll::Ready(Some(Ok(channel)))
+                }
+                (Poll::Ready(Some(NewConnection::Filtered)), _) | (_, Poll::Ready(())) => {
+                    trace!("Filtered a connection; {} open.", self.open_connections());
+                    continue;
+                }
+                (Poll::Pending, Poll::Pending) => return Poll::Pending,
+                (Poll::Ready(None), Poll::Pending) => {
+                    if *self.open_connections() > 0 {
+                        trace!(
+                            "Listener closed; {} open connections.",
+                            self.open_connections()
+                        );
+                        return Poll::Pending;
+                    }
+                    trace!("Shutting down listener: all connections closed, and no more coming.");
+                    return Poll::Ready(None);
+                }
+            }
+        }
+    }
+}

rpc/src/server/mod.rs

@@ -0,0 +1,609 @@
+// Copyright 2018 Google LLC
+//
+// Use of this source code is governed by an MIT-style
+// license that can be found in the LICENSE file or at
+// https://opensource.org/licenses/MIT.
+
+//! Provides a server that concurrently handles many connections sending multiplexed requests.
+
+use crate::{
+    context::Context, util::deadline_compat, util::AsDuration, util::Compact, ClientMessage,
+    ClientMessageKind, Request, Response, ServerError, Transport,
+};
+use fnv::FnvHashMap;
+use futures::{
+    channel::mpsc,
+    future::{abortable, AbortHandle},
+    prelude::*,
+    ready,
+    stream::Fuse,
+    task::{LocalWaker, Poll},
+    try_ready,
+};
+use humantime::format_rfc3339;
+use log::{debug, error, info, trace, warn};
+use pin_utils::{unsafe_pinned, unsafe_unpinned};
+use std::{
+    error::Error as StdError,
+    io,
+    marker::PhantomData,
+    net::SocketAddr,
+    pin::Pin,
+    time::{Instant, SystemTime},
+};
+use tokio_timer::timeout;
+use trace::{self, TraceId};
+
+mod filter;
+
+/// Manages clients, serving multiplexed requests over each connection.
+#[derive(Debug)]
+pub struct Server<Req, Resp> {
+    config: Config,
+    ghost: PhantomData<(Req, Resp)>,
+}
+
+impl<Req, Resp> Default for Server<Req, Resp> {
+    fn default() -> Self {
+        new(Config::default())
+    }
+}
+
+/// Settings that control the behavior of the server.
+#[non_exhaustive]
+#[derive(Clone, Debug)]
+pub struct Config {
+    /// The maximum number of clients that can be connected to the server at once. When at the
+    /// limit, existing connections are honored and new connections are rejected.
+    pub max_connections: usize,
+    /// The maximum number of clients per IP address that can be connected to the server at once.
+    /// When an IP is at the limit, existing connections are honored and new connections on that IP
+    /// address are rejected.
+    pub max_connections_per_ip: usize,
+    /// The maximum number of requests that can be in flight for each client. When a client is at
+    /// the in-flight request limit, existing requests are fulfilled and new requests are rejected.
+    /// Rejected requests are sent a response error.
+    pub max_in_flight_requests_per_connection: usize,
+    /// The number of responses per client that can be buffered server-side before being sent.
+    /// `pending_response_buffer` controls the buffer size of the channel that a server's
+    /// response tasks use to send responses to the client handler task.
+    pub pending_response_buffer: usize,
+}
+
+impl Default for Config {
+    fn default() -> Self {
+        Config {
+            max_connections: 1_000_000,
+            max_connections_per_ip: 1_000,
+            max_in_flight_requests_per_connection: 1_000,
+            pending_response_buffer: 100,
+        }
+    }
+}
+
+/// Returns a new server with configuration specified `config`.
+pub fn new<Req, Resp>(config: Config) -> Server<Req, Resp> {
+    Server {
+        config,
+        ghost: PhantomData,
+    }
+}
+
+impl<Req, Resp> Server<Req, Resp> {
+    /// Returns the config for this server.
+    pub fn config(&self) -> &Config {
+        &self.config
+    }
+
+    /// Returns a stream of the incoming connections to the server.
+    pub fn incoming<S, T>(
+        self,
+        listener: S,
+    ) -> impl Stream<Item = io::Result<Channel<Req, Resp, T>>>
+    where
+        Req: Send,
+        Resp: Send,
+        S: Stream<Item = io::Result<T>>,
+        T: Transport<Item = ClientMessage<Req>, SinkItem = Response<Resp>> + Send,
+    {
+        self::filter::ConnectionFilter::filter(listener, self.config.clone())
+    }
+}
+
+/// The future driving the server.
+#[derive(Debug)]
+pub struct Running<S, F> {
+    incoming: S,
+    request_handler: F,
+}
+
+impl<S, F> Running<S, F> {
+    unsafe_pinned!(incoming: S);
+    unsafe_unpinned!(request_handler: F);
+}
+
+impl<S, T, Req, Resp, F, Fut> Future for Running<S, F>
+where
+    S: Sized + Stream<Item = io::Result<Channel<Req, Resp, T>>>,
+    Req: Send + 'static,
+    Resp: Send + 'static,
+    T: Transport<Item = ClientMessage<Req>, SinkItem = Response<Resp>> + Send + 'static,
+    F: FnOnce(Context, Req) -> Fut + Send + 'static + Clone,
+    Fut: Future<Output = io::Result<Resp>> + Send + 'static,
+{
+    type Output = ();
+
+    fn poll(mut self: Pin<&mut Self>, cx: &LocalWaker) -> Poll<()> {
+        while let Some(channel) = ready!(self.incoming().poll_next(cx)) {
+            match channel {
+                Ok(channel) => {
+                    let peer = channel.client_addr;
+                    if let Err(e) =
+                        crate::spawn(channel.respond_with(self.request_handler().clone()))
+                    {
+                        warn!("[{}] Failed to spawn connection handler: {:?}", peer, e);
+                    }
+                }
+                Err(e) => {
+                    warn!("Incoming connection error: {}", e);
+                }
+            }
+        }
+        info!("Server shutting down.");
+        return Poll::Ready(());
+    }
+}
+
+/// A utility trait enabling a stream to fluently chain a request handler.
+pub trait Handler<T, Req, Resp>
+where
+    Self: Sized + Stream<Item = io::Result<Channel<Req, Resp, T>>>,
+    Req: Send,
+    Resp: Send,
+    T: Transport<Item = ClientMessage<Req>, SinkItem = Response<Resp>> + Send,
+{
+    /// Responds to all requests with `request_handler`.
+    fn respond_with<F, Fut>(self, request_handler: F) -> Running<Self, F>
+    where
+        F: FnOnce(Context, Req) -> Fut + Send + 'static + Clone,
+        Fut: Future<Output = io::Result<Resp>> + Send + 'static,
+    {
+        Running {
+            incoming: self,
+            request_handler,
+        }
+    }
+}
+
+impl<T, Req, Resp, S> Handler<T, Req, Resp> for S
+where
+    S: Sized + Stream<Item = io::Result<Channel<Req, Resp, T>>>,
+    Req: Send,
+    Resp: Send,
+    T: Transport<Item = ClientMessage<Req>, SinkItem = Response<Resp>> + Send,
+{}
+
+/// Responds to all requests with `request_handler`.
+/// The server end of an open connection with a client.
+#[derive(Debug)]
+pub struct Channel<Req, Resp, T> {
+    /// Writes responses to the wire and reads requests off the wire.
+    transport: Fuse<T>,
+    /// Signals the connection is closed when `Channel` is dropped.
+    closed_connections: mpsc::UnboundedSender<SocketAddr>,
+    /// Channel limits to prevent unlimited resource usage.
+    config: Config,
+    /// The address of the server connected to.
+    client_addr: SocketAddr,
+    /// Types the request and response.
+    ghost: PhantomData<(Req, Resp)>,
+}
+
+impl<Req, Resp, T> Drop for Channel<Req, Resp, T> {
+    fn drop(&mut self) {
+        trace!("[{}] Closing channel.", self.client_addr);
+
+        // Even in a bounded channel, each connection would have a guaranteed slot, so using
+        // an unbounded sender is actually no different. And, the bound is on the maximum number
+        // of open connections.
+        if self
+            .closed_connections
+            .unbounded_send(self.client_addr)
+            .is_err()
+        {
+            warn!(
+                "[{}] Failed to send closed connection message.",
+                self.client_addr
+            );
+        }
+    }
+}
+
+impl<Req, Resp, T> Channel<Req, Resp, T> {
+    unsafe_pinned!(transport: Fuse<T>);
+}
+
+impl<Req, Resp, T> Channel<Req, Resp, T>
+where
+    T: Transport<Item = ClientMessage<Req>, SinkItem = Response<Resp>> + Send,
+    Req: Send,
+    Resp: Send,
+{
+    pub(crate) fn start_send(
+        self: &mut Pin<&mut Self>,
+        response: Response<Resp>,
+    ) -> io::Result<()> {
+        self.transport().start_send(response)
+    }
+
+    pub(crate) fn poll_ready(self: &mut Pin<&mut Self>, cx: &LocalWaker) -> Poll<io::Result<()>> {
+        self.transport().poll_ready(cx)
+    }
+
+    pub(crate) fn poll_flush(self: &mut Pin<&mut Self>, cx: &LocalWaker) -> Poll<io::Result<()>> {
+        self.transport().poll_flush(cx)
+    }
+
+    pub(crate) fn poll_next(
+        self: &mut Pin<&mut Self>,
+        cx: &LocalWaker,
+    ) -> Poll<Option<io::Result<ClientMessage<Req>>>> {
+        self.transport().poll_next(cx)
+    }
+
+    /// Returns the address of the client connected to the channel.
+    pub fn client_addr(&self) -> &SocketAddr {
+        &self.client_addr
+    }
+
+    /// Respond to requests coming over the channel with `f`. Returns a future that drives the
+    /// responses and resolves when the connection is closed.
+    pub fn respond_with<F, Fut>(self, f: F) -> impl Future<Output = ()>
+    where
+        F: FnOnce(Context, Req) -> Fut + Send + 'static + Clone,
+        Fut: Future<Output = io::Result<Resp>> + Send + 'static,
+        Req: 'static,
+        Resp: 'static,
+    {
+        let (responses_tx, responses) = mpsc::channel(self.config.pending_response_buffer);
+        let responses = responses.fuse();
+        let peer = self.client_addr;
+
+        ClientHandler {
+            channel: self,
+            f,
+            pending_responses: responses,
+            responses_tx,
+            in_flight_requests: FnvHashMap::default(),
+        }
+        .unwrap_or_else(move |e| {
+            info!("[{}] ClientHandler errored out: {}", peer, e);
+        })
+    }
+}
+
+#[derive(Debug)]
+struct ClientHandler<Req, Resp, T, F> {
+    channel: Channel<Req, Resp, T>,
+    /// Responses waiting to be written to the wire.
+    pending_responses: Fuse<mpsc::Receiver<(Context, Response<Resp>)>>,
+    /// Handed out to request handlers to fan in responses.
+    responses_tx: mpsc::Sender<(Context, Response<Resp>)>,
+    /// Number of requests currently being responded to.
+    in_flight_requests: FnvHashMap<u64, AbortHandle>,
+    /// Request handler.
+    f: F,
+}
+
+impl<Req, Resp, T, F> ClientHandler<Req, Resp, T, F> {
+    unsafe_pinned!(channel: Channel<Req, Resp, T>);
+    unsafe_pinned!(in_flight_requests: FnvHashMap<u64, AbortHandle>);
+    unsafe_pinned!(pending_responses: Fuse<mpsc::Receiver<(Context, Response<Resp>)>>);
+    unsafe_pinned!(responses_tx: mpsc::Sender<(Context, Response<Resp>)>);
+    // For this to be safe, field f must be private, and code in this module must never
+    // construct PinMut<F>.
+    unsafe_unpinned!(f: F);
+}
+
+impl<Req, Resp, T, F, Fut> ClientHandler<Req, Resp, T, F>
+where
+    Req: Send + 'static,
+    Resp: Send + 'static,
+    T: Transport<Item = ClientMessage<Req>, SinkItem = Response<Resp>> + Send,
+    F: FnOnce(Context, Req) -> Fut + Send + 'static + Clone,
+    Fut: Future<Output = io::Result<Resp>> + Send + 'static,
+{
+    /// If at max in-flight requests, check that there's room to immediately write a throttled
+    /// response.
+    fn poll_ready_if_throttling(
+        self: &mut Pin<&mut Self>,
+        cx: &LocalWaker,
+    ) -> Poll<io::Result<()>> {
+        if self.in_flight_requests.len()
+            >= self.channel.config.max_in_flight_requests_per_connection
+        {
+            let peer = self.channel().client_addr;
+
+            while let Poll::Pending = self.channel().poll_ready(cx)? {
+                info!(
+                    "[{}] In-flight requests at max ({}), and transport is not ready.",
+                    peer,
+                    self.in_flight_requests().len(),
+                );
+                try_ready!(self.channel().poll_flush(cx));
+            }
+        }
+        Poll::Ready(Ok(()))
+    }
+
+    fn pump_read(self: &mut Pin<&mut Self>, cx: &LocalWaker) -> Poll<Option<io::Result<()>>> {
+        ready!(self.poll_ready_if_throttling(cx)?);
+
+        Poll::Ready(match ready!(self.channel().poll_next(cx)?) {
+            Some(message) => {
+                match message.message {
+                    ClientMessageKind::Request(request) => {
+                        self.handle_request(message.trace_context, request)?;
+                    }
+                    ClientMessageKind::Cancel { request_id } => {
+                        self.cancel_request(&message.trace_context, request_id);
+                    }
+                }
+                Some(Ok(()))
+            }
+            None => {
+                trace!("[{}] Read half closed", self.channel.client_addr);
+                None
+            }
+        })
+    }
+
+    fn pump_write(
+        self: &mut Pin<&mut Self>,
+        cx: &LocalWaker,
+        read_half_closed: bool,
+    ) -> Poll<Option<io::Result<()>>> {
+        match self.poll_next_response(cx)? {
+            Poll::Ready(Some((_, response))) => {
+                self.channel().start_send(response)?;
+                Poll::Ready(Some(Ok(())))
+            }
+            Poll::Ready(None) => {
+                // Shutdown can't be done before we finish pumping out remaining responses.
+                ready!(self.channel().poll_flush(cx)?);
+                Poll::Ready(None)
+            }
+            Poll::Pending => {
+                // No more requests to process, so flush any requests buffered in the transport.
+                ready!(self.channel().poll_flush(cx)?);
+
+                // Being here means there are no staged requests and all written responses are
+                // fully flushed. So, if the read half is closed and there are no in-flight
+                // requests, then we can close the write half.
+                if read_half_closed && self.in_flight_requests().is_empty() {
+                    Poll::Ready(None)
+                } else {
+                    Poll::Pending
+                }
+            }
+        }
+    }
+
+    fn poll_next_response(
+        self: &mut Pin<&mut Self>,
+        cx: &LocalWaker,
+    ) -> Poll<Option<io::Result<(Context, Response<Resp>)>>> {
+        // Ensure there's room to write a response.
+        while let Poll::Pending = self.channel().poll_ready(cx)? {
+            ready!(self.channel().poll_flush(cx)?);
+        }
+
+        let peer = self.channel().client_addr;
+
+        match ready!(self.pending_responses().poll_next(cx)) {
+            Some((ctx, response)) => {
+                if let Some(_) = self.in_flight_requests().remove(&response.request_id) {
+                    self.in_flight_requests().compact(0.1);
+                }
+                trace!(
+                    "[{}/{}] Staging response. In-flight requests = {}.",
+                    ctx.trace_id(),
+                    peer,
+                    self.in_flight_requests().len(),
+                );
+                return Poll::Ready(Some(Ok((ctx, response))));
+            }
+            None => {
+                // This branch likely won't happen, since the ClientHandler is holding a Sender.
+                trace!("[{}] No new responses.", peer);
+                Poll::Ready(None)
+            }
+        }
+    }
+
+    fn handle_request(
+        self: &mut Pin<&mut Self>,
+        trace_context: trace::Context,
+        request: Request<Req>,
+    ) -> io::Result<()> {
+        let request_id = request.id;
+        let peer = self.channel().client_addr;
+        let ctx = Context {
+            deadline: request.deadline,
+            trace_context,
+        };
+        let request = request.message;
+
+        if self.in_flight_requests().len()
+            >= self.channel().config.max_in_flight_requests_per_connection
+        {
+            debug!(
+                "[{}/{}] Client has reached in-flight request limit ({}/{}).",
+                ctx.trace_id(),
+                peer,
+                self.in_flight_requests().len(),
+                self.channel().config.max_in_flight_requests_per_connection
+            );
+
+            self.channel().start_send(Response {
+                request_id,
+                message: Err(ServerError {
+                    kind: io::ErrorKind::WouldBlock,
+                    detail: Some("Server throttled the request.".into()),
+                }),
+            })?;
+            return Ok(());
+        }
+
+        let deadline = ctx.deadline;
+        let timeout = deadline.as_duration();
+        trace!(
+            "[{}/{}] Received request with deadline {} (timeout {:?}).",
+            ctx.trace_id(),
+            peer,
+            format_rfc3339(deadline),
+            timeout,
+        );
+        let mut response_tx = self.responses_tx().clone();
+
+        let trace_id = *ctx.trace_id();
+        let response = self.f().clone()(ctx.clone(), request);
+        let response = deadline_compat::Deadline::new(response, Instant::now() + timeout).then(
+            async move |result| {
+                let response = Response {
+                    request_id,
+                    message: match result {
+                        Ok(message) => Ok(message),
+                        Err(e) => Err(make_server_error(e, trace_id, peer, deadline)),
+                    },
+                };
+                trace!("[{}/{}] Sending response.", trace_id, peer);
+                await!(response_tx.send((ctx, response)).unwrap_or_else(|_| ()));
+            },
+        );
+        let (abortable_response, abort_handle) = abortable(response);
+        crate::spawn(abortable_response.map(|_| ())).map_err(|e| {
+            io::Error::new(
+                io::ErrorKind::Other,
+                format!(
+                    "Could not spawn response task. Is shutdown: {}",
+                    e.is_shutdown()
+                ),
+            )
+        })?;
+        self.in_flight_requests().insert(request_id, abort_handle);
+        Ok(())
+    }
+
+    fn cancel_request(self: &mut Pin<&mut Self>, trace_context: &trace::Context, request_id: u64) {
+        // It's possible the request was already completed, so it's fine
+        // if this is None.
+        if let Some(cancel_handle) = self.in_flight_requests().remove(&request_id) {
+            self.in_flight_requests().compact(0.1);
+
+            cancel_handle.abort();
+            let remaining = self.in_flight_requests().len();
+            trace!(
+                "[{}/{}] Request canceled. In-flight requests = {}",
+                trace_context.trace_id,
+                self.channel.client_addr,
+                remaining,
+            );
+        } else {
+            trace!(
+                "[{}/{}] Received cancellation, but response handler \
+                 is already complete.",
+                trace_context.trace_id,
+                self.channel.client_addr
+            );
+        }
+    }
+}
+
+impl<Req, Resp, T, F, Fut> Future for ClientHandler<Req, Resp, T, F>
+where
+    Req: Send + 'static,
+    Resp: Send + 'static,
+    T: Transport<Item = ClientMessage<Req>, SinkItem = Response<Resp>> + Send,
+    F: FnOnce(Context, Req) -> Fut + Send + 'static + Clone,
+    Fut: Future<Output = io::Result<Resp>> + Send + 'static,
+{
+    type Output = io::Result<()>;
+
+    fn poll(mut self: Pin<&mut Self>, cx: &LocalWaker) -> Poll<io::Result<()>> {
+        trace!("[{}] ClientHandler::poll", self.channel.client_addr);
+        loop {
+            let read = self.pump_read(cx)?;
+            match (read, self.pump_write(cx, read == Poll::Ready(None))?) {
+                (Poll::Ready(None), Poll::Ready(None)) => {
+                    info!("[{}] Client disconnected.", self.channel.client_addr);
+                    return Poll::Ready(Ok(()));
+                }
+                (read @ Poll::Ready(Some(())), write) | (read, write @ Poll::Ready(Some(()))) => {
+                    trace!(
+                        "[{}] read: {:?}, write: {:?}.",
+                        self.channel.client_addr,
+                        read,
+                        write
+                    )
+                }
+                (read, write) => {
+                    trace!(
+                        "[{}] read: {:?}, write: {:?} (not ready).",
+                        self.channel.client_addr,
+                        read,
+                        write,
+                    );
+                    return Poll::Pending;
+                }
+            }
+        }
+    }
+}
+
+fn make_server_error(
+    e: timeout::Error<io::Error>,
+    trace_id: TraceId,
+    peer: SocketAddr,
+    deadline: SystemTime,
+) -> ServerError {
+    if e.is_elapsed() {
+        debug!(
+            "[{}/{}] Response did not complete before deadline of {}s.",
+            trace_id,
+            peer,
+            format_rfc3339(deadline)
+        );
+        // No point in responding, since the client will have dropped the request.
+        ServerError {
+            kind: io::ErrorKind::TimedOut,
+            detail: Some(format!(
+                "Response did not complete before deadline of {}s.",
+                format_rfc3339(deadline)
+            )),
+        }
+    } else if e.is_timer() {
+        error!(
+            "[{}/{}] Response failed because of an issue with a timer: {}",
+            trace_id, peer, e
+        );
+
+        ServerError {
+            kind: io::ErrorKind::Other,
+            detail: Some(format!("{}", e)),
+        }
+    } else if e.is_inner() {
+        let e = e.into_inner().unwrap();
+        ServerError {
+            kind: e.kind(),
+            detail: Some(e.description().into()),
+        }
+    } else {
+        error!("[{}/{}] Unexpected response failure: {}", trace_id, peer, e);
+
+        ServerError {
+            kind: io::ErrorKind::Other,
+            detail: Some(format!("Server unexpectedly failed to respond: {}", e)),
+        }
+    }
+}

rpc/src/transport/channel.rs

@@ -0,0 +1,158 @@
+// Copyright 2018 Google LLC
+//
+// Use of this source code is governed by an MIT-style
+// license that can be found in the LICENSE file or at
+// https://opensource.org/licenses/MIT.
+
+//! Transports backed by in-memory channels.
+
+use crate::Transport;
+use futures::{channel::mpsc, task::LocalWaker, Poll, Sink, Stream};
+use pin_utils::unsafe_pinned;
+use std::pin::Pin;
+use std::{
+    io,
+    net::{IpAddr, Ipv4Addr, SocketAddr},
+};
+
+/// Returns two unbounded channel peers. Each [`Stream`] yields items sent through the other's
+/// [`Sink`].
+pub fn unbounded<SinkItem, Item>() -> (
+    UnboundedChannel<SinkItem, Item>,
+    UnboundedChannel<Item, SinkItem>,
+) {
+    let (tx1, rx2) = mpsc::unbounded();
+    let (tx2, rx1) = mpsc::unbounded();
+    (
+        UnboundedChannel { tx: tx1, rx: rx1 },
+        UnboundedChannel { tx: tx2, rx: rx2 },
+    )
+}
+
+/// A bi-directional channel backed by an [`UnboundedSender`](mpsc::UnboundedSender)
+/// and [`UnboundedReceiver`](mpsc::UnboundedReceiver).
+#[derive(Debug)]
+pub struct UnboundedChannel<Item, SinkItem> {
+    rx: mpsc::UnboundedReceiver<Item>,
+    tx: mpsc::UnboundedSender<SinkItem>,
+}
+
+impl<Item, SinkItem> UnboundedChannel<Item, SinkItem> {
+    unsafe_pinned!(rx: mpsc::UnboundedReceiver<Item>);
+    unsafe_pinned!(tx: mpsc::UnboundedSender<SinkItem>);
+}
+
+impl<Item, SinkItem> Stream for UnboundedChannel<Item, SinkItem> {
+    type Item = Result<Item, io::Error>;
+
+    fn poll_next(mut self: Pin<&mut Self>, cx: &LocalWaker) -> Poll<Option<io::Result<Item>>> {
+        self.rx().poll_next(cx).map(|option| option.map(Ok))
+    }
+}
+
+impl<Item, SinkItem> Sink for UnboundedChannel<Item, SinkItem> {
+    type SinkItem = SinkItem;
+    type SinkError = io::Error;
+
+    fn poll_ready(mut self: Pin<&mut Self>, cx: &LocalWaker) -> Poll<io::Result<()>> {
+        self.tx()
+            .poll_ready(cx)
+            .map_err(|_| io::Error::from(io::ErrorKind::NotConnected))
+    }
+
+    fn start_send(mut self: Pin<&mut Self>, item: SinkItem) -> io::Result<()> {
+        self.tx()
+            .start_send(item)
+            .map_err(|_| io::Error::from(io::ErrorKind::NotConnected))
+    }
+
+    fn poll_flush(mut self: Pin<&mut Self>, cx: &LocalWaker) -> Poll<Result<(), Self::SinkError>> {
+        self.tx()
+            .poll_flush(cx)
+            .map_err(|_| io::Error::from(io::ErrorKind::NotConnected))
+    }
+
+    fn poll_close(mut self: Pin<&mut Self>, cx: &LocalWaker) -> Poll<io::Result<()>> {
+        self.tx()
+            .poll_close(cx)
+            .map_err(|_| io::Error::from(io::ErrorKind::NotConnected))
+    }
+}
+
+impl<Item, SinkItem> Transport for UnboundedChannel<Item, SinkItem> {
+    type Item = Item;
+    type SinkItem = SinkItem;
+
+    fn peer_addr(&self) -> io::Result<SocketAddr> {
+        Ok(SocketAddr::new(IpAddr::V4(Ipv4Addr::LOCALHOST), 0))
+    }
+
+    fn local_addr(&self) -> io::Result<SocketAddr> {
+        Ok(SocketAddr::new(IpAddr::V4(Ipv4Addr::LOCALHOST), 0))
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::{
+        client, context,
+        server::{Handler, Server},
+        transport,
+    };
+    use futures::{compat::TokioDefaultSpawner, prelude::*, stream};
+    use log::trace;
+    use std::io;
+
+    #[test]
+    fn integration() {
+        let _ = env_logger::try_init();
+        crate::init(TokioDefaultSpawner);
+
+        let (client_channel, server_channel) = transport::channel::unbounded();
+        let server = Server::<String, u64>::default()
+            .incoming(stream::once(future::ready(Ok(server_channel))))
+            .respond_with(|_ctx, request| {
+                future::ready(request.parse::<u64>().map_err(|_| {
+                    io::Error::new(
+                        io::ErrorKind::InvalidInput,
+                        format!("{:?} is not an int", request),
+                    )
+                }))
+            });
+
+        let responses = async {
+            let mut client = await!(client::new(client::Config::default(), client_channel))?;
+
+            let response1 = await!(client.call(context::current(), "123".into()));
+            let response2 = await!(client.call(context::current(), "abc".into()));
+
+            Ok::<_, io::Error>((response1, response2))
+        };
+
+        let (response1, response2) =
+            run_future(server.join(responses.unwrap_or_else(|e| panic!(e)))).1;
+
+        trace!("response1: {:?}, response2: {:?}", response1, response2);
+
+        assert!(response1.is_ok());
+        assert_eq!(response1.ok().unwrap(), 123);
+
+        assert!(response2.is_err());
+        assert_eq!(response2.err().unwrap().kind(), io::ErrorKind::InvalidInput);
+    }
+
+    fn run_future<F>(f: F) -> F::Output
+    where
+        F: Future + Send + 'static,
+        F::Output: Send + 'static,
+    {
+        let (tx, rx) = futures::channel::oneshot::channel();
+        tokio::run(
+            f.map(|result| tx.send(result).unwrap_or_else(|_| unreachable!()))
+                .boxed()
+                .unit_error()
+                .compat(),
+        );
+        futures::executor::block_on(rx).unwrap()
+    }
+}

rpc/src/transport/mod.rs

@@ -0,0 +1,121 @@
+// Copyright 2018 Google LLC
+//
+// Use of this source code is governed by an MIT-style
+// license that can be found in the LICENSE file or at
+// https://opensource.org/licenses/MIT.
+
+//! Provides a [`Transport`] trait as well as implementations.
+//!
+//! The rpc crate is transport- and protocol-agnostic. Any transport that impls [`Transport`]
+//! can be plugged in, using whatever protocol it wants.
+
+use futures::prelude::*;
+use std::{
+    io,
+    net::SocketAddr,
+    pin::Pin,
+    task::{LocalWaker, Poll},
+};
+
+pub mod channel;
+
+/// A bidirectional stream ([`Sink`] + [`Stream`]) of messages.
+pub trait Transport
+where
+    Self: Stream<Item = io::Result<<Self as Transport>::Item>>,
+    Self: Sink<SinkItem = <Self as Transport>::SinkItem, SinkError = io::Error>,
+{
+    /// The type read off the transport.
+    type Item;
+    /// The type written to the transport.
+    type SinkItem;
+
+    /// The address of the remote peer this transport is in communication with.
+    fn peer_addr(&self) -> io::Result<SocketAddr>;
+    /// The address of the local half of this transport.
+    fn local_addr(&self) -> io::Result<SocketAddr>;
+}
+
+/// Returns a new Transport backed by the given Stream + Sink and connecting addresses.
+pub fn new<S, Item>(
+    inner: S,
+    peer_addr: SocketAddr,
+    local_addr: SocketAddr,
+) -> impl Transport<Item = Item, SinkItem = S::SinkItem>
+where
+    S: Stream<Item = io::Result<Item>>,
+    S: Sink<SinkError = io::Error>,
+{
+    TransportShim {
+        inner,
+        peer_addr,
+        local_addr,
+    }
+}
+
+/// A transport created by adding peers to a Stream + Sink.
+#[derive(Debug)]
+struct TransportShim<S> {
+    peer_addr: SocketAddr,
+    local_addr: SocketAddr,
+    inner: S,
+}
+
+impl<S> TransportShim<S> {
+    pin_utils::unsafe_pinned!(inner: S);
+}
+
+impl<S> Stream for TransportShim<S>
+where
+    S: Stream,
+{
+    type Item = S::Item;
+
+    fn poll_next(mut self: Pin<&mut Self>, waker: &LocalWaker) -> Poll<Option<S::Item>> {
+        self.inner().poll_next(waker)
+    }
+}
+
+impl<S> Sink for TransportShim<S>
+where
+    S: Sink,
+{
+    type SinkItem = S::SinkItem;
+    type SinkError = S::SinkError;
+
+    fn start_send(mut self: Pin<&mut Self>, item: S::SinkItem) -> Result<(), S::SinkError> {
+        self.inner().start_send(item)
+    }
+
+    fn poll_ready(mut self: Pin<&mut Self>, waker: &LocalWaker) -> Poll<Result<(), S::SinkError>> {
+        self.inner().poll_ready(waker)
+    }
+
+    fn poll_flush(mut self: Pin<&mut Self>, waker: &LocalWaker) -> Poll<Result<(), S::SinkError>> {
+        self.inner().poll_flush(waker)
+    }
+
+    fn poll_close(mut self: Pin<&mut Self>, waker: &LocalWaker) -> Poll<Result<(), S::SinkError>> {
+        self.inner().poll_close(waker)
+    }
+}
+
+impl<S, Item> Transport for TransportShim<S>
+where
+    S: Stream + Sink,
+    Self: Stream<Item = io::Result<Item>>,
+    Self: Sink<SinkItem = S::SinkItem, SinkError = io::Error>,
+{
+    type Item = Item;
+    type SinkItem = S::SinkItem;
+
+    /// The address of the remote peer this transport is in communication with.
+    fn peer_addr(&self) -> io::Result<SocketAddr> {
+        Ok(self.peer_addr)
+    }
+
+    /// The address of the local half of this transport.
+    fn local_addr(&self) -> io::Result<SocketAddr> {
+        Ok(self.local_addr)
+    }
+}

rpc/src/util/deadline_compat.rs

@@ -0,0 +1,69 @@
+// Copyright 2018 Google LLC
+//
+// Use of this source code is governed by an MIT-style
+// license that can be found in the LICENSE file or at
+// https://opensource.org/licenses/MIT.
+
+use futures::{
+    compat::{Compat01As03, Future01CompatExt},
+    prelude::*,
+    ready,
+    task::{LocalWaker, Poll},
+};
+use pin_utils::unsafe_pinned;
+use std::pin::Pin;
+use std::time::Instant;
+use tokio_timer::{timeout, Delay};
+
+#[must_use = "futures do nothing unless polled"]
+#[derive(Debug)]
+pub struct Deadline<T> {
+    future: T,
+    delay: Compat01As03<Delay>,
+}
+
+impl<T> Deadline<T> {
+    unsafe_pinned!(future: T);
+    unsafe_pinned!(delay: Compat01As03<Delay>);
+
+    /// Create a new `Deadline` that completes when `future` completes or when
+    /// `deadline` is reached.
+    pub fn new(future: T, deadline: Instant) -> Deadline<T> {
+        Deadline::new_with_delay(future, Delay::new(deadline))
+    }
+
+    pub(crate) fn new_with_delay(future: T, delay: Delay) -> Deadline<T> {
+        Deadline {
+            future,
+            delay: delay.compat(),
+        }
+    }
+
+    /// Gets a mutable reference to the underlying future in this deadline.
+    pub fn get_mut(&mut self) -> &mut T {
+        &mut self.future
+    }
+}
+impl<T> Future for Deadline<T>
+where
+    T: TryFuture,
+{
+    type Output = Result<T::Ok, timeout::Error<T::Error>>;
+
+    fn poll(mut self: Pin<&mut Self>, waker: &LocalWaker) -> Poll<Self::Output> {
+        // First, try polling the future
+        match self.future().try_poll(waker) {
+            Poll::Ready(Ok(v)) => return Poll::Ready(Ok(v)),
+            Poll::Pending => {}
+            Poll::Ready(Err(e)) => return Poll::Ready(Err(timeout::Error::inner(e))),
+        }
+
+        let delay = self.delay().poll_unpin(waker);
+
+        // Now check the timer
+        match ready!(delay) {
+            Ok(_) => Poll::Ready(Err(timeout::Error::elapsed())),
+            Err(e) => Poll::Ready(Err(timeout::Error::timer(e))),
+        }
+    }
+}

rpc/src/util/mod.rs

@@ -0,0 +1,46 @@
+// Copyright 2018 Google LLC
+//
+// Use of this source code is governed by an MIT-style
+// license that can be found in the LICENSE file or at
+// https://opensource.org/licenses/MIT.
+
+use std::{
+    collections::HashMap,
+    hash::{BuildHasher, Hash},
+    time::{Duration, SystemTime},
+};
+
+pub mod deadline_compat;
+#[cfg(feature = "serde")]
+pub mod serde;
+
+/// Types that can be represented by a [`Duration`].
+pub trait AsDuration {
+    fn as_duration(&self) -> Duration;
+}
+
+impl AsDuration for SystemTime {
+    /// Duration of 0 if self is earlier than [`SystemTime::now`].
+    fn as_duration(&self) -> Duration {
+        self.duration_since(SystemTime::now()).unwrap_or_default()
+    }
+}
+
+/// Collection compaction; configurable `shrink_to_fit`.
+pub trait Compact {
+    /// Compacts space if the ratio of length : capacity is less than `usage_ratio_threshold`.
+    fn compact(&mut self, usage_ratio_threshold: f64);
+}
+
+impl<K, V, H> Compact for HashMap<K, V, H>
+where
+    K: Eq + Hash,
+    H: BuildHasher,
+{
+    fn compact(&mut self, usage_ratio_threshold: f64) {
+        let usage_ratio = self.len() as f64 / self.capacity() as f64;
+        if usage_ratio < usage_ratio_threshold {
+            self.shrink_to_fit();
+        }
+    }
+}

rpc/src/util/serde.rs

@@ -0,0 +1,95 @@
+// Copyright 2018 Google LLC
+//
+// Use of this source code is governed by an MIT-style
+// license that can be found in the LICENSE file or at
+// https://opensource.org/licenses/MIT.
+
+use serde::{Deserialize, Deserializer, Serialize, Serializer};
+use std::{
+    io,
+    time::{Duration, SystemTime},
+};
+
+/// Serializes `system_time` as a `u64` equal to the number of seconds since the epoch.
+pub fn serialize_epoch_secs<S>(system_time: &SystemTime, serializer: S) -> Result<S::Ok, S::Error>
+where
+    S: Serializer,
+{
+    system_time
+        .duration_since(SystemTime::UNIX_EPOCH)
+        .unwrap_or(Duration::from_secs(0))
+        .as_secs() // Only care about second precision
+        .serialize(serializer)
+}
+
+/// Deserializes [`SystemTime`] from a `u64` equal to the number of seconds since the epoch.
+pub fn deserialize_epoch_secs<'de, D>(deserializer: D) -> Result<SystemTime, D::Error>
+where
+    D: Deserializer<'de>,
+{
+    Ok(SystemTime::UNIX_EPOCH + Duration::from_secs(u64::deserialize(deserializer)?))
+}
+
+/// Serializes [`io::ErrorKind`] as a `u32`.
+pub fn serialize_io_error_kind_as_u32<S>(
+    kind: &io::ErrorKind,
+    serializer: S,
+) -> Result<S::Ok, S::Error>
+where
+    S: Serializer,
+{
+    use std::io::ErrorKind::*;
+    match *kind {
+        NotFound => 0,
+        PermissionDenied => 1,
+        ConnectionRefused => 2,
+        ConnectionReset => 3,
+        ConnectionAborted => 4,
+        NotConnected => 5,
+        AddrInUse => 6,
+        AddrNotAvailable => 7,
+        BrokenPipe => 8,
+        AlreadyExists => 9,
+        WouldBlock => 10,
+        InvalidInput => 11,
+        InvalidData => 12,
+        TimedOut => 13,
+        WriteZero => 14,
+        Interrupted => 15,
+        Other => 16,
+        UnexpectedEof => 17,
+        _ => 16,
+    }
+    .serialize(serializer)
+}
+
+/// Deserializes [`io::ErrorKind`] from a `u32`.
+pub fn deserialize_io_error_kind_from_u32<'de, D>(
+    deserializer: D,
+) -> Result<io::ErrorKind, D::Error>
+where
+    D: Deserializer<'de>,
+{
+    use std::io::ErrorKind::*;
+    Ok(match u32::deserialize(deserializer)? {
+        0 => NotFound,
+        1 => PermissionDenied,
+        2 => ConnectionRefused,
+        3 => ConnectionReset,
+        4 => ConnectionAborted,
+        5 => NotConnected,
+        6 => AddrInUse,
+        7 => AddrNotAvailable,
+        8 => BrokenPipe,
+        9 => AlreadyExists,
+        10 => WouldBlock,
+        11 => InvalidInput,
+        12 => InvalidData,
+        13 => TimedOut,
+        14 => WriteZero,
+        15 => Interrupted,
+        16 => Other,
+        17 => UnexpectedEof,
+        _ => Other,
+    })
+}

rustfmt.toml

@@ -1 +0,0 @@
-reorder_imports = true

src/errors.rs

@@ -1,91 +0,0 @@
-// Copyright 2016 Google Inc. All Rights Reserved.
-//
-// Licensed under the MIT License, <LICENSE or http://opensource.org/licenses/MIT>.
-// This file may not be copied, modified, or distributed except according to those terms.
-
-use serde::{Deserialize, Serialize};
-use std::{fmt, io};
-use std::error::Error as StdError;
-
-/// All errors that can occur during the use of tarpc.
-#[derive(Debug)]
-pub enum Error<E> {
-    /// Any IO error.
-    Io(io::Error),
-    /// Error deserializing the server response.
-    ///
-    /// Typically this indicates a faulty implementation of `serde::Serialize` or
-    /// `serde::Deserialize`.
-    ResponseDeserialize(::bincode::Error),
-    /// Error deserializing the client request.
-    ///
-    /// Typically this indicates a faulty implementation of `serde::Serialize` or
-    /// `serde::Deserialize`.
-    RequestDeserialize(String),
-    /// The server was unable to reply to the rpc for some reason.
-    ///
-    /// This is a service-specific error. Its type is individually specified in the
-    /// `service!` macro for each rpc.
-    App(E),
-}
-
-impl<'a, E: StdError + Deserialize<'a> + Serialize + Send + 'static> fmt::Display for Error<E> {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        match *self {
-            Error::ResponseDeserialize(ref e) => write!(f, r#"{}: "{}""#, self.description(), e),
-            Error::RequestDeserialize(ref e) => write!(f, r#"{}: "{}""#, self.description(), e),
-            Error::App(ref e) => fmt::Display::fmt(e, f),
-            Error::Io(ref e) => fmt::Display::fmt(e, f),
-        }
-    }
-}
-
-impl<'a, E: StdError + Deserialize<'a> + Serialize + Send + 'static> StdError for Error<E> {
-    fn description(&self) -> &str {
-        match *self {
-            Error::ResponseDeserialize(_) => "The client failed to deserialize the response.",
-            Error::RequestDeserialize(_) => "The server failed to deserialize the request.",
-            Error::App(ref e) => e.description(),
-            Error::Io(ref e) => e.description(),
-        }
-    }
-
-    fn cause(&self) -> Option<&StdError> {
-        match *self {
-            Error::ResponseDeserialize(ref e) => e.cause(),
-            Error::RequestDeserialize(_) | Error::App(_) => None,
-            Error::Io(ref e) => e.cause(),
-        }
-    }
-}
-
-impl<E> From<io::Error> for Error<E> {
-    fn from(err: io::Error) -> Self {
-        Error::Io(err)
-    }
-}
-
-impl<E> From<WireError<E>> for Error<E> {
-    fn from(err: WireError<E>) -> Self {
-        match err {
-            WireError::RequestDeserialize(s) => Error::RequestDeserialize(s),
-            WireError::App(e) => Error::App(e),
-        }
-    }
-}
-
-/// A serializable, server-supplied error.
-#[doc(hidden)]
-#[derive(Deserialize, Serialize, Clone, Debug)]
-pub enum WireError<E> {
-    /// Server-side error in deserializing the client request.
-    RequestDeserialize(String),
-    /// The server was unable to reply to the rpc for some reason.
-    App(E),
-}
-
-/// Convert `native_tls::Error` to `std::io::Error`
-#[cfg(feature = "tls")]
-pub fn native_to_io(e: ::native_tls::Error) -> io::Error {
-    io::Error::new(io::ErrorKind::Other, e)
-}

src/future/client.rs

@@ -1,278 +0,0 @@
-// Copyright 2016 Google Inc. All Rights Reserved.
-//
-// Licensed under the MIT License, <LICENSE or http://opensource.org/licenses/MIT>.
-// This file may not be copied, modified, or distributed except according to those terms.
-
-use {REMOTE, bincode};
-use future::server::Response;
-use futures::{self, Future, future};
-use protocol::Proto;
-use serde::Serialize;
-use serde::de::DeserializeOwned;
-use std::fmt;
-use std::io;
-use std::net::SocketAddr;
-use stream_type::StreamType;
-use tokio_core::net::TcpStream;
-use tokio_core::reactor;
-use tokio_proto::BindClient as ProtoBindClient;
-use tokio_proto::multiplex::ClientService;
-use tokio_service::Service;
-
-cfg_if! {
-    if #[cfg(feature = "tls")] {
-        use errors::native_to_io;
-        use tls::client::Context;
-        use tokio_tls::TlsConnectorExt;
-    } else {}
-}
-
-/// Additional options to configure how the client connects and operates.
-#[derive(Debug)]
-pub struct Options {
-    /// Max packet size in bytes.
-    max_payload_size: u64,
-    reactor: Option<Reactor>,
-    #[cfg(feature = "tls")]
-    tls_ctx: Option<Context>,
-}
-
-impl Default for Options {
-    #[cfg(feature = "tls")]
-    fn default() -> Self {
-        Options {
-            max_payload_size: 2 << 20,
-            reactor: None,
-            tls_ctx: None,
-        }
-    }
-
-    #[cfg(not(feature = "tls"))]
-    fn default() -> Self {
-        Options {
-            max_payload_size: 2 << 20,
-            reactor: None,
-        }
-    }
-}
-
-impl Options {
-    /// Set the max payload size in bytes. The default is 2 << 20 (2 MiB).
-    pub fn max_payload_size(mut self, bytes: u64) -> Self {
-        self.max_payload_size = bytes;
-        self
-    }
-
-    /// Drive using the given reactor handle.
-    pub fn handle(mut self, handle: reactor::Handle) -> Self {
-        self.reactor = Some(Reactor::Handle(handle));
-        self
-    }
-
-    /// Drive using the given reactor remote.
-    pub fn remote(mut self, remote: reactor::Remote) -> Self {
-        self.reactor = Some(Reactor::Remote(remote));
-        self
-    }
-
-    /// Connect using the given `Context`
-    #[cfg(feature = "tls")]
-    pub fn tls(mut self, tls_ctx: Context) -> Self {
-        self.tls_ctx = Some(tls_ctx);
-        self
-    }
-}
-
-enum Reactor {
-    Handle(reactor::Handle),
-    Remote(reactor::Remote),
-}
-
-impl fmt::Debug for Reactor {
-    fn fmt(&self, f: &mut fmt::Formatter) -> Result<(), fmt::Error> {
-        const HANDLE: &str = "Reactor::Handle";
-        const HANDLE_INNER: &str = "Handle { .. }";
-        const REMOTE: &str = "Reactor::Remote";
-        const REMOTE_INNER: &str = "Remote { .. }";
-
-        match *self {
-            Reactor::Handle(_) => f.debug_tuple(HANDLE).field(&HANDLE_INNER).finish(),
-            Reactor::Remote(_) => f.debug_tuple(REMOTE).field(&REMOTE_INNER).finish(),
-        }
-    }
-}
-
-#[doc(hidden)]
-pub struct Client<Req, Resp, E>
-where
-    Req: Serialize + 'static,
-    Resp: DeserializeOwned + 'static,
-    E: DeserializeOwned + 'static,
-{
-    inner: ClientService<StreamType, Proto<Req, Response<Resp, E>>>,
-}
-
-impl<Req, Resp, E> Clone for Client<Req, Resp, E>
-where
-    Req: Serialize + 'static,
-    Resp: DeserializeOwned + 'static,
-    E: DeserializeOwned + 'static,
-{
-    fn clone(&self) -> Self {
-        Client {
-            inner: self.inner.clone(),
-        }
-    }
-}
-
-impl<Req, Resp, E> Service for Client<Req, Resp, E>
-where
-    Req: Serialize + Send + 'static,
-    Resp: DeserializeOwned + Send + 'static,
-    E: DeserializeOwned + Send + 'static,
-{
-    type Request = Req;
-    type Response = Resp;
-    type Error = ::Error<E>;
-    type Future = ResponseFuture<Req, Resp, E>;
-
-    fn call(&self, request: Self::Request) -> Self::Future {
-        fn identity<T>(t: T) -> T {
-            t
-        }
-        self.inner
-            .call(request)
-            .map(Self::map_err as _)
-            .map_err(::Error::from as _)
-            .and_then(identity as _)
-    }
-}
-
-impl<Req, Resp, E> Client<Req, Resp, E>
-where
-    Req: Serialize + 'static,
-    Resp: DeserializeOwned + 'static,
-    E: DeserializeOwned + 'static,
-{
-    fn bind(handle: &reactor::Handle, tcp: StreamType, max_payload_size: u64) -> Self
-    where
-        Req: Serialize + Send + 'static,
-        Resp: DeserializeOwned + Send + 'static,
-        E: DeserializeOwned + Send + 'static,
-    {
-        let inner = Proto::new(max_payload_size).bind_client(handle, tcp);
-        Client { inner }
-    }
-
-    fn map_err(resp: WireResponse<Resp, E>) -> Result<Resp, ::Error<E>> {
-        resp.map(|r| r.map_err(::Error::from))
-            .map_err(::Error::ResponseDeserialize)
-            .and_then(|r| r)
-    }
-}
-
-impl<Req, Resp, E> fmt::Debug for Client<Req, Resp, E>
-where
-    Req: Serialize + 'static,
-    Resp: DeserializeOwned + 'static,
-    E: DeserializeOwned + 'static,
-{
-    fn fmt(&self, f: &mut fmt::Formatter) -> Result<(), fmt::Error> {
-        write!(f, "Client {{ .. }}")
-    }
-}
-
-/// Extension methods for clients.
-pub trait ClientExt: Sized {
-    /// The type of the future returned when calling `connect`.
-    type ConnectFut: Future<Item = Self, Error = io::Error>;
-
-    /// Connects to a server located at the given address, using the given options.
-    fn connect(addr: SocketAddr, options: Options) -> Self::ConnectFut;
-}
-
-/// A future that resolves to a `Client` or an `io::Error`.
-pub type ConnectFuture<Req, Resp, E> = futures::Flatten<
-    futures::MapErr<
-        futures::Oneshot<io::Result<Client<Req, Resp, E>>>,
-        fn(futures::Canceled) -> io::Error,
-    >,
->;
-
-impl<Req, Resp, E> ClientExt for Client<Req, Resp, E>
-where
-    Req: Serialize + Send + 'static,
-    Resp: DeserializeOwned + Send + 'static,
-    E: DeserializeOwned + Send + 'static,
-{
-    type ConnectFut = ConnectFuture<Req, Resp, E>;
-
-    fn connect(addr: SocketAddr, options: Options) -> Self::ConnectFut {
-        // we need to do this for tls because we need to avoid moving the entire `Options`
-        // struct into the `setup` closure, since `Reactor` is not `Send`.
-        #[cfg(feature = "tls")]
-        let mut options = options;
-        #[cfg(feature = "tls")]
-        let tls_ctx = options.tls_ctx.take();
-
-        let max_payload_size = options.max_payload_size;
-
-        let connect = move |handle: &reactor::Handle| {
-            let handle2 = handle.clone();
-            TcpStream::connect(&addr, handle)
-                .and_then(move |socket| {
-                    // TODO(https://github.com/tokio-rs/tokio-proto/issues/132): move this into the
-                    // ServerProto impl
-                    #[cfg(feature = "tls")]
-                    match tls_ctx {
-                        Some(tls_ctx) => {
-                            future::Either::A(
-                                tls_ctx
-                                    .tls_connector
-                                    .connect_async(&tls_ctx.domain, socket)
-                                    .map(StreamType::Tls)
-                                    .map_err(native_to_io),
-                            )
-                        }
-                        None => future::Either::B(future::ok(StreamType::Tcp(socket))),
-                    }
-                    #[cfg(not(feature = "tls"))] future::ok(StreamType::Tcp(socket))
-                })
-                .map(move |tcp| Client::bind(&handle2, tcp, max_payload_size))
-        };
-        let (tx, rx) = futures::oneshot();
-        let setup = move |handle: &reactor::Handle| {
-            connect(handle).then(move |result| {
-                // If send fails it means the client no longer cared about connecting.
-                let _ = tx.send(result);
-                Ok(())
-            })
-        };
-
-        match options.reactor {
-            Some(Reactor::Handle(handle)) => {
-                handle.spawn(setup(&handle));
-            }
-            Some(Reactor::Remote(remote)) => {
-                remote.spawn(setup);
-            }
-            None => {
-                REMOTE.spawn(setup);
-            }
-        }
-        fn panic(canceled: futures::Canceled) -> io::Error {
-            unreachable!(canceled)
-        }
-        rx.map_err(panic as _).flatten()
-    }
-}
-
-type ResponseFuture<Req, Resp, E> =
-    futures::AndThen<futures::MapErr<
-    futures::Map<<ClientService<StreamType, Proto<Req, Response<Resp, E>>> as Service>::Future,
-                 fn(WireResponse<Resp, E>) -> Result<Resp, ::Error<E>>>,
-        fn(io::Error) -> ::Error<E>>,
-                 Result<Resp, ::Error<E>>,
-                 fn(Result<Resp, ::Error<E>>) -> Result<Resp, ::Error<E>>>;
-
-type WireResponse<R, E> = Result<Response<R, E>, bincode::Error>;

src/future/mod.rs

@@ -1,4 +0,0 @@
-/// Provides the base client stubs used by the service macro.
-pub mod client;
-/// Provides the base server boilerplate used by service implementations.
-pub mod server;

src/future/server/connection.rs

@@ -1,76 +0,0 @@
-use futures::unsync;
-use std::io;
-use tokio_service::{NewService, Service};
-
-#[derive(Debug)]
-pub enum Action {
-    Increment,
-    Decrement,
-}
-
-#[derive(Clone, Debug)]
-pub struct Tracker {
-    pub tx: unsync::mpsc::UnboundedSender<Action>,
-}
-
-impl Tracker {
-    pub fn pair() -> (Self, unsync::mpsc::UnboundedReceiver<Action>) {
-        let (tx, rx) = unsync::mpsc::unbounded();
-        (Self { tx }, rx)
-    }
-
-    pub fn increment(&self) {
-        let _ = self.tx.unbounded_send(Action::Increment);
-    }
-
-    pub fn decrement(&self) {
-        debug!("Closing connection");
-        let _ = self.tx.unbounded_send(Action::Decrement);
-    }
-}
-
-#[derive(Debug)]
-pub struct TrackingService<S> {
-    pub service: S,
-    pub tracker: Tracker,
-}
-
-#[derive(Debug)]
-pub struct TrackingNewService<S> {
-    pub new_service: S,
-    pub connection_tracker: Tracker,
-}
-
-impl<S: Service> Service for TrackingService<S> {
-    type Request = S::Request;
-    type Response = S::Response;
-    type Error = S::Error;
-    type Future = S::Future;
-
-    fn call(&self, req: Self::Request) -> Self::Future {
-        trace!("Calling service.");
-        self.service.call(req)
-    }
-}
-
-impl<S> Drop for TrackingService<S> {
-    fn drop(&mut self) {
-        debug!("Dropping ConnnectionTrackingService.");
-        self.tracker.decrement();
-    }
-}
-
-impl<S: NewService> NewService for TrackingNewService<S> {
-    type Request = S::Request;
-    type Response = S::Response;
-    type Error = S::Error;
-    type Instance = TrackingService<S::Instance>;
-
-    fn new_service(&self) -> io::Result<Self::Instance> {
-        self.connection_tracker.increment();
-        Ok(TrackingService {
-            service: self.new_service.new_service()?,
-            tracker: self.connection_tracker.clone(),
-        })
-    }
-}

src/future/server/mod.rs

@@ -1,471 +0,0 @@
-// Copyright 2016 Google Inc. All Rights Reserved.
-//
-// Licensed under the MIT License, <LICENSE or http://opensource.org/licenses/MIT>.
-// This file may not be copied, modified, or distributed except according to those terms.
-
-use {bincode, net2};
-use errors::WireError;
-use futures::{Async, Future, Poll, Stream, future as futures};
-use protocol::Proto;
-use serde::Serialize;
-use serde::de::DeserializeOwned;
-use std::fmt;
-use std::io;
-use std::net::SocketAddr;
-use stream_type::StreamType;
-use tokio_core::net::{Incoming, TcpListener, TcpStream};
-use tokio_core::reactor;
-use tokio_io::{AsyncRead, AsyncWrite};
-use tokio_proto::BindServer;
-use tokio_service::NewService;
-
-mod connection;
-mod shutdown;
-
-cfg_if! {
-    if #[cfg(feature = "tls")] {
-        use native_tls::{self, TlsAcceptor};
-        use tokio_tls::{AcceptAsync, TlsAcceptorExt, TlsStream};
-        use errors::native_to_io;
-    } else {}
-}
-
-pub use self::shutdown::{Shutdown, ShutdownFuture};
-
-/// A handle to a bound server.
-#[derive(Clone, Debug)]
-pub struct Handle {
-    addr: SocketAddr,
-    shutdown: Shutdown,
-}
-
-impl Handle {
-    /// Returns a hook for shutting down the server.
-    pub fn shutdown(&self) -> &Shutdown {
-        &self.shutdown
-    }
-
-    /// The socket address the server is bound to.
-    pub fn addr(&self) -> SocketAddr {
-        self.addr
-    }
-}
-
-enum Acceptor {
-    Tcp,
-    #[cfg(feature = "tls")]
-    Tls(TlsAcceptor),
-}
-
-struct Accept {
-    #[cfg(feature = "tls")]
-    inner: futures::Either<
-        futures::MapErr<
-            futures::Map<AcceptAsync<TcpStream>, fn(TlsStream<TcpStream>) -> StreamType>,
-            fn(native_tls::Error) -> io::Error,
-        >,
-        futures::FutureResult<StreamType, io::Error>,
-    >,
-    #[cfg(not(feature = "tls"))]
-    inner: futures::FutureResult<StreamType, io::Error>,
-}
-
-impl Future for Accept {
-    type Item = StreamType;
-    type Error = io::Error;
-
-    fn poll(&mut self) -> Poll<Self::Item, Self::Error> {
-        self.inner.poll()
-    }
-}
-
-impl Acceptor {
-    // TODO(https://github.com/tokio-rs/tokio-proto/issues/132): move this into the ServerProto impl
-    #[cfg(feature = "tls")]
-    fn accept(&self, socket: TcpStream) -> Accept {
-        Accept {
-            inner: match *self {
-                Acceptor::Tls(ref tls_acceptor) => {
-                    futures::Either::A(
-                        tls_acceptor
-                            .accept_async(socket)
-                            .map(StreamType::Tls as _)
-                            .map_err(native_to_io),
-                    )
-                }
-                Acceptor::Tcp => futures::Either::B(futures::ok(StreamType::Tcp(socket))),
-            },
-        }
-    }
-
-    #[cfg(not(feature = "tls"))]
-    fn accept(&self, socket: TcpStream) -> Accept {
-        Accept {
-            inner: futures::ok(StreamType::Tcp(socket)),
-        }
-    }
-}
-
-#[cfg(feature = "tls")]
-impl From<Options> for Acceptor {
-    fn from(options: Options) -> Self {
-        match options.tls_acceptor {
-            Some(tls_acceptor) => Acceptor::Tls(tls_acceptor),
-            None => Acceptor::Tcp,
-        }
-    }
-}
-
-#[cfg(not(feature = "tls"))]
-impl From<Options> for Acceptor {
-    fn from(_: Options) -> Self {
-        Acceptor::Tcp
-    }
-}
-
-impl fmt::Debug for Acceptor {
-    fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
-        use self::Acceptor::*;
-        #[cfg(feature = "tls")]
-        const TLS: &str = "TlsAcceptor { .. }";
-
-        match *self {
-            Tcp => fmt.debug_tuple("Acceptor::Tcp").finish(),
-            #[cfg(feature = "tls")]
-            Tls(_) => fmt.debug_tuple("Acceptor::Tls").field(&TLS).finish(),
-        }
-    }
-}
-
-impl fmt::Debug for Accept {
-    fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
-        fmt.debug_struct("Accept").finish()
-    }
-}
-
-#[derive(Debug)]
-struct AcceptStream<S> {
-    stream: S,
-    acceptor: Acceptor,
-    future: Option<Accept>,
-}
-
-impl<S> Stream for AcceptStream<S>
-where
-    S: Stream<Item = (TcpStream, SocketAddr), Error = io::Error>,
-{
-    type Item = <Accept as Future>::Item;
-    type Error = io::Error;
-
-    fn poll(&mut self) -> Poll<Option<Self::Item>, io::Error> {
-        if self.future.is_none() {
-            let stream = match try_ready!(self.stream.poll()) {
-                None => return Ok(Async::Ready(None)),
-                Some((stream, _)) => stream,
-            };
-            self.future = Some(self.acceptor.accept(stream));
-        }
-        assert!(self.future.is_some());
-        match self.future.as_mut().unwrap().poll() {
-            Ok(Async::Ready(e)) => {
-                self.future = None;
-                Ok(Async::Ready(Some(e)))
-            }
-            Err(e) => {
-                self.future = None;
-                Err(e)
-            }
-            Ok(Async::NotReady) => Ok(Async::NotReady),
-        }
-    }
-}
-
-/// Additional options to configure how the server operates.
-pub struct Options {
-    /// Max packet size in bytes.
-    max_payload_size: u64,
-    #[cfg(feature = "tls")]
-    tls_acceptor: Option<TlsAcceptor>,
-}
-
-impl Default for Options {
-    #[cfg(not(feature = "tls"))]
-    fn default() -> Self {
-        Options {
-            max_payload_size: 2 << 20,
-        }
-    }
-
-    #[cfg(feature = "tls")]
-    fn default() -> Self {
-        Options {
-            max_payload_size: 2 << 20,
-            tls_acceptor: None,
-        }
-    }
-}
-
-impl Options {
-    /// Set the max payload size in bytes. The default is 2 << 20 (2 MiB).
-    pub fn max_payload_size(mut self, bytes: u64) -> Self {
-        self.max_payload_size = bytes;
-        self
-    }
-
-    /// Sets the `TlsAcceptor`
-    #[cfg(feature = "tls")]
-    pub fn tls(mut self, tls_acceptor: TlsAcceptor) -> Self {
-        self.tls_acceptor = Some(tls_acceptor);
-        self
-    }
-}
-
-impl fmt::Debug for Options {
-    fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
-        #[cfg(feature = "tls")]
-        const SOME: &str = "Some(_)";
-        #[cfg(feature = "tls")]
-        const NONE: &str = "None";
-
-        let mut debug_struct = fmt.debug_struct("Options");
-        #[cfg(feature = "tls")]
-        debug_struct.field(
-            "tls_acceptor",
-            if self.tls_acceptor.is_some() {
-                &SOME
-            } else {
-                &NONE
-            },
-        );
-        debug_struct.finish()
-    }
-}
-
-/// A message from server to client.
-#[doc(hidden)]
-pub type Response<T, E> = Result<T, WireError<E>>;
-
-#[doc(hidden)]
-pub fn listen<S, Req, Resp, E>(new_service: S,
-                               addr: SocketAddr,
-                               handle: &reactor::Handle,
-                               options: Options)
-                               -> io::Result<(Handle, Listen<S, Req, Resp, E>)>
-    where S: NewService<Request = Result<Req, bincode::Error>,
-                        Response = Response<Resp, E>,
-                        Error = io::Error> + 'static,
-          Req: DeserializeOwned + 'static,
-          Resp: Serialize + 'static,
-          E: Serialize + 'static
-{
-    let (addr, shutdown, server) = listen_with(
-        new_service,
-        addr,
-        handle,
-        options.max_payload_size,
-        Acceptor::from(options),
-    )?;
-    Ok((
-        Handle {
-            addr: addr,
-            shutdown: shutdown,
-        },
-        server,
-    ))
-}
-
-/// Spawns a service that binds to the given address using the given handle.
-fn listen_with<S, Req, Resp, E>(new_service: S,
-                                addr: SocketAddr,
-                                handle: &reactor::Handle,
-                                max_payload_size: u64,
-                                acceptor: Acceptor)
-                                -> io::Result<(SocketAddr, Shutdown, Listen<S, Req, Resp, E>)>
-    where S: NewService<Request = Result<Req, bincode::Error>,
-                        Response = Response<Resp, E>,
-                        Error = io::Error> + 'static,
-          Req: DeserializeOwned + 'static,
-          Resp: Serialize + 'static,
-          E: Serialize + 'static
-{
-    let listener = listener(&addr, handle)?;
-    let addr = listener.local_addr()?;
-    debug!("Listening on {}.", addr);
-
-    let handle = handle.clone();
-    let (connection_tracker, shutdown, shutdown_future) = shutdown::Watcher::triple();
-    let server = BindStream {
-        handle: handle,
-        new_service: connection::TrackingNewService {
-            connection_tracker: connection_tracker,
-            new_service: new_service,
-        },
-        stream: AcceptStream {
-            stream: listener.incoming(),
-            acceptor: acceptor,
-            future: None,
-        },
-        max_payload_size: max_payload_size,
-    };
-
-    let server = AlwaysOkUnit(server.select(shutdown_future));
-    Ok((addr, shutdown, Listen { inner: server }))
-}
-
-fn listener(addr: &SocketAddr, handle: &reactor::Handle) -> io::Result<TcpListener> {
-    const PENDING_CONNECTION_BACKLOG: i32 = 1024;
-
-    let builder = match *addr {
-        SocketAddr::V4(_) => net2::TcpBuilder::new_v4(),
-        SocketAddr::V6(_) => net2::TcpBuilder::new_v6(),
-    }?;
-    configure_tcp(&builder)?;
-    builder.reuse_address(true)?;
-    builder
-        .bind(addr)?
-        .listen(PENDING_CONNECTION_BACKLOG)
-        .and_then(|l| TcpListener::from_listener(l, addr, handle))
-}
-
-#[cfg(unix)]
-fn configure_tcp(tcp: &net2::TcpBuilder) -> io::Result<()> {
-    use net2::unix::UnixTcpBuilderExt;
-    tcp.reuse_port(true)?;
-    Ok(())
-}
-
-#[cfg(windows)]
-fn configure_tcp(_tcp: &net2::TcpBuilder) -> io::Result<()> {
-    Ok(())
-}
-
-struct BindStream<S, St> {
-    handle: reactor::Handle,
-    new_service: connection::TrackingNewService<S>,
-    stream: St,
-    max_payload_size: u64,
-}
-
-impl<S, St> fmt::Debug for BindStream<S, St>
-where
-    S: fmt::Debug,
-    St: fmt::Debug,
-{
-    fn fmt(&self, f: &mut fmt::Formatter) -> Result<(), fmt::Error> {
-        f.debug_struct("BindStream")
-            .field("handle", &self.handle)
-            .field("new_service", &self.new_service)
-            .field("stream", &self.stream)
-            .finish()
-    }
-}
-
-impl<S, Req, Resp, E, I, St> BindStream<S, St>
-    where S: NewService<Request = Result<Req, bincode::Error>,
-                        Response = Response<Resp, E>,
-                        Error = io::Error> + 'static,
-          Req: DeserializeOwned + 'static,
-          Resp: Serialize + 'static,
-          E: Serialize + 'static,
-          I: AsyncRead + AsyncWrite + 'static,
-          St: Stream<Item = I, Error = io::Error>
-{
-    fn bind_each(&mut self) -> Poll<(), io::Error> {
-        loop {
-            match try!(self.stream.poll()) {
-                Async::Ready(Some(socket)) => {
-                    Proto::new(self.max_payload_size).bind_server(&self.handle,
-                                                                  socket,
-                                                                  self.new_service.new_service()?);
-                }
-                Async::Ready(None) => return Ok(Async::Ready(())),
-                Async::NotReady => return Ok(Async::NotReady),
-            }
-        }
-    }
-}
-
-impl<S, Req, Resp, E, I, St> Future for BindStream<S, St>
-    where S: NewService<Request = Result<Req, bincode::Error>,
-                        Response = Response<Resp, E>,
-                        Error = io::Error> + 'static,
-          Req: DeserializeOwned + 'static,
-          Resp: Serialize + 'static,
-          E: Serialize + 'static,
-          I: AsyncRead + AsyncWrite + 'static,
-          St: Stream<Item = I, Error = io::Error>
-{
-    type Item = ();
-    type Error = ();
-
-    fn poll(&mut self) -> Poll<Self::Item, Self::Error> {
-        match self.bind_each() {
-            Ok(Async::Ready(())) => Ok(Async::Ready(())),
-            Ok(Async::NotReady) => Ok(Async::NotReady),
-            Err(e) => {
-                error!("While processing incoming connections: {}", e);
-                Err(())
-            }
-        }
-    }
-}
-
-/// The future representing a running server.
-#[doc(hidden)]
-pub struct Listen<S, Req, Resp, E>
-    where S: NewService<Request = Result<Req, bincode::Error>,
-                        Response = Response<Resp, E>,
-                        Error = io::Error> + 'static,
-          Req: DeserializeOwned + 'static,
-          Resp: Serialize + 'static,
-          E: Serialize + 'static
-{
-    inner: AlwaysOkUnit<futures::Select<BindStream<S, AcceptStream<Incoming>>, shutdown::Watcher>>,
-}
-
-impl<S, Req, Resp, E> Future for Listen<S, Req, Resp, E>
-    where S: NewService<Request = Result<Req, bincode::Error>,
-                        Response = Response<Resp, E>,
-                        Error = io::Error> + 'static,
-          Req: DeserializeOwned + 'static,
-          Resp: Serialize + 'static,
-          E: Serialize + 'static
-{
-    type Item = ();
-    type Error = ();
-
-    fn poll(&mut self) -> Poll<(), ()> {
-        self.inner.poll()
-    }
-}
-
-impl<S, Req, Resp, E> fmt::Debug for Listen<S, Req, Resp, E>
-    where S: NewService<Request = Result<Req, bincode::Error>,
-                        Response = Response<Resp, E>,
-                        Error = io::Error> + 'static,
-          Req: DeserializeOwned + 'static,
-          Resp: Serialize + 'static,
-          E: Serialize + 'static
-{
-    fn fmt(&self, f: &mut fmt::Formatter) -> Result<(), fmt::Error> {
-        f.debug_struct("Listen").finish()
-    }
-}
-
-#[derive(Debug)]
-struct AlwaysOkUnit<F>(F);
-
-impl<F> Future for AlwaysOkUnit<F>
-where
-    F: Future,
-{
-    type Item = ();
-    type Error = ();
-
-    fn poll(&mut self) -> Poll<(), ()> {
-        match self.0.poll() {
-            Ok(Async::Ready(_)) | Err(_) => Ok(Async::Ready(())),
-            Ok(Async::NotReady) => Ok(Async::NotReady),
-        }
-    }
-}

src/future/server/shutdown.rs

@@ -1,182 +0,0 @@
-
-
-use super::{AlwaysOkUnit, connection};
-use futures::{Async, Future, Poll, Stream, future as futures, stream};
-use futures::sync::{mpsc, oneshot};
-use futures::unsync;
-
-/// A hook to shut down a running server.
-#[derive(Clone, Debug)]
-pub struct Shutdown {
-    tx: mpsc::UnboundedSender<oneshot::Sender<()>>,
-}
-
-/// A future that resolves when server shutdown completes.
-#[derive(Debug)]
-pub struct ShutdownFuture {
-    inner: futures::Either<futures::FutureResult<(), ()>, AlwaysOkUnit<oneshot::Receiver<()>>>,
-}
-
-impl Future for ShutdownFuture {
-    type Item = ();
-    type Error = ();
-
-    fn poll(&mut self) -> Poll<(), ()> {
-        self.inner.poll()
-    }
-}
-
-impl Shutdown {
-    /// Initiates an orderly server shutdown.
-    ///
-    /// First, the server enters lameduck mode, in which
-    /// existing connections are honored but no new connections are accepted. Then, once all
-    /// connections are closed, it initates total shutdown.
-    ///
-    /// The returned future resolves when the server is completely shut down.
-    pub fn shutdown(&self) -> ShutdownFuture {
-        let (tx, rx) = oneshot::channel();
-        let inner = if self.tx.unbounded_send(tx).is_err() {
-            trace!("Server already initiated shutdown.");
-            futures::Either::A(futures::ok(()))
-        } else {
-            futures::Either::B(AlwaysOkUnit(rx))
-        };
-        ShutdownFuture { inner: inner }
-    }
-}
-
-#[derive(Debug)]
-pub struct Watcher {
-    shutdown_rx: stream::Take<mpsc::UnboundedReceiver<oneshot::Sender<()>>>,
-    connections: unsync::mpsc::UnboundedReceiver<connection::Action>,
-    queued_error: Option<()>,
-    shutdown: Option<oneshot::Sender<()>>,
-    done: bool,
-    num_connections: u64,
-}
-
-impl Watcher {
-    pub fn triple() -> (connection::Tracker, Shutdown, Self) {
-        let (connection_tx, connections) = connection::Tracker::pair();
-        let (shutdown_tx, shutdown_rx) = mpsc::unbounded();
-        (
-            connection_tx,
-            Shutdown { tx: shutdown_tx },
-            Watcher {
-                shutdown_rx: shutdown_rx.take(1),
-                connections: connections,
-                queued_error: None,
-                shutdown: None,
-                done: false,
-                num_connections: 0,
-            },
-        )
-    }
-
-    fn process_connection(&mut self, action: connection::Action) {
-        match action {
-            connection::Action::Increment => self.num_connections += 1,
-            connection::Action::Decrement => self.num_connections -= 1,
-        }
-    }
-
-    fn poll_shutdown_requests(&mut self) -> Poll<Option<()>, ()> {
-        Ok(Async::Ready(match try_ready!(self.shutdown_rx.poll()) {
-            Some(tx) => {
-                debug!("Received shutdown request.");
-                self.shutdown = Some(tx);
-                Some(())
-            }
-            None => None,
-        }))
-    }
-
-    fn poll_connections(&mut self) -> Poll<Option<()>, ()> {
-        Ok(Async::Ready(match try_ready!(self.connections.poll()) {
-            Some(action) => {
-                self.process_connection(action);
-                Some(())
-            }
-            None => None,
-        }))
-    }
-
-    fn poll_shutdown_requests_and_connections(&mut self) -> Poll<Option<()>, ()> {
-        if let Some(e) = self.queued_error.take() {
-            return Err(e);
-        }
-
-        match try!(self.poll_shutdown_requests()) {
-            Async::NotReady => {
-                match try_ready!(self.poll_connections()) {
-                    Some(()) => Ok(Async::Ready(Some(()))),
-                    None => Ok(Async::NotReady),
-                }
-            }
-            Async::Ready(None) => {
-                match try_ready!(self.poll_connections()) {
-                    Some(()) => Ok(Async::Ready(Some(()))),
-                    None => Ok(Async::Ready(None)),
-                }
-            }
-            Async::Ready(Some(())) => {
-                match self.poll_connections() {
-                    Err(e) => {
-                        self.queued_error = Some(e);
-                        Ok(Async::Ready(Some(())))
-                    }
-                    Ok(Async::NotReady) | Ok(Async::Ready(None)) | Ok(Async::Ready(Some(()))) => {
-                        Ok(Async::Ready(Some(())))
-                    }
-                }
-            }
-        }
-    }
-
-    fn should_continue(&mut self) -> bool {
-        match self.shutdown.take() {
-            Some(shutdown) => {
-                debug!("Lameduck mode: {} open connections", self.num_connections);
-                if self.num_connections == 0 {
-                    debug!("Shutting down.");
-                    // Not required for the shutdown future to be waited on, so this
-                    // can fail (which is fine).
-                    let _ = shutdown.send(());
-                    false
-                } else {
-                    self.shutdown = Some(shutdown);
-                    true
-                }
-            }
-            None => true,
-        }
-    }
-
-    fn process_request(&mut self) -> Poll<Option<()>, ()> {
-        if self.done {
-            return Ok(Async::Ready(None));
-        }
-        if self.should_continue() {
-            self.poll_shutdown_requests_and_connections()
-        } else {
-            self.done = true;
-            Ok(Async::Ready(None))
-        }
-    }
-}
-
-impl Future for Watcher {
-    type Item = ();
-    type Error = ();
-
-    fn poll(&mut self) -> Poll<(), ()> {
-        loop {
-            match try!(self.process_request()) {
-                Async::Ready(Some(())) => continue,
-                Async::Ready(None) => return Ok(Async::Ready(())),
-                Async::NotReady => return Ok(Async::NotReady),
-            }
-        }
-    }
-}

src/lib.rs

@@ -1,213 +0,0 @@
-// Copyright 2016 Google Inc. All Rights Reserved.
-//
-// Licensed under the MIT License, <LICENSE or http://opensource.org/licenses/MIT>.
-// This file may not be copied, modified, or distributed except according to those terms.
-
-//! tarpc is an RPC framework for rust with a focus on ease of use. Defining a
-//! service can be done in just a few lines of code, and most of the boilerplate of
-//! writing a server is taken care of for you.
-//!
-//! ## What is an RPC framework?
-//! "RPC" stands for "Remote Procedure Call," a function call where the work of
-//! producing the return value is being done somewhere else. When an rpc function is
-//! invoked, behind the scenes the function contacts some other process somewhere
-//! and asks them to evaluate the function instead. The original function then
-//! returns the value produced by the other process.
-//!
-//! RPC frameworks are a fundamental building block of most microservices-oriented
-//! architectures. Two well-known ones are [gRPC](http://www.grpc.io) and
-//! [Cap'n Proto](https://capnproto.org/).
-//!
-//! tarpc differentiates itself from other RPC frameworks by defining the schema in code,
-//! rather than in a separate language such as .proto. This means there's no separate compilation
-//! process, and no cognitive context switching between different languages. Additionally, it
-//! works with the community-backed library serde: any serde-serializable type can be used as
-//! arguments to tarpc fns.
-//!
-//! Example usage:
-//!
-//! ```
-//! #![feature(plugin, use_extern_macros, proc_macro_path_invoc)]
-//! #![plugin(tarpc_plugins)]
-//!
-//! #[macro_use]
-//! extern crate tarpc;
-//! extern crate tokio_core;
-//!
-//! use tarpc::sync::{client, server};
-//! use tarpc::sync::client::ClientExt;
-//! use tarpc::util::Never;
-//! use tokio_core::reactor;
-//! use std::sync::mpsc;
-//! use std::thread;
-//!
-//! service! {
-//!     rpc hello(name: String) -> String;
-//! }
-//!
-//! #[derive(Clone)]
-//! struct HelloServer;
-//!
-//! impl SyncService for HelloServer {
-//!     fn hello(&self, name: String) -> Result<String, Never> {
-//!         Ok(format!("Hello, {}!", name))
-//!     }
-//! }
-//!
-//! fn main() {
-//!     let (tx, rx) = mpsc::channel();
-//!     thread::spawn(move || {
-//!         let mut handle = HelloServer.listen("localhost:10000",
-//!             server::Options::default()).unwrap();
-//!         tx.send(handle.addr()).unwrap();
-//!         handle.run();
-//!     });
-//!     let addr = rx.recv().unwrap();
-//!     let client = SyncClient::connect(addr, client::Options::default()).unwrap();
-//!     println!("{}", client.hello("Mom".to_string()).unwrap());
-//! }
-//! ```
-//!
-//! Example usage with TLS:
-//!
-//! ```no-run
-//! #![feature(plugin, use_extern_macros, proc_macro_path_invoc)]
-//! #![plugin(tarpc_plugins)]
-//!
-//! #[macro_use]
-//! extern crate tarpc;
-//!
-//! use tarpc::sync::{client, server};
-//! use tarpc::sync::client::ClientExt;
-//! use tarpc::tls;
-//! use tarpc::util::Never;
-//! use tarpc::native_tls::{TlsAcceptor, Pkcs12};
-//!
-//! service! {
-//!     rpc hello(name: String) -> String;
-//! }
-//!
-//! #[derive(Clone)]
-//! struct HelloServer;
-//!
-//! impl SyncService for HelloServer {
-//!     fn hello(&self, name: String) -> Result<String, Never> {
-//!         Ok(format!("Hello, {}!", name))
-//!     }
-//! }
-//!
-//! fn get_acceptor() -> TlsAcceptor {
-//!      let buf = include_bytes!("test/identity.p12");
-//!      let pkcs12 = Pkcs12::from_der(buf, "password").unwrap();
-//!      TlsAcceptor::builder(pkcs12).unwrap().build().unwrap()
-//! }
-//!
-//! fn main() {
-//!     let addr = "localhost:10000";
-//!     let acceptor = get_acceptor();
-//!     let _server = HelloServer.listen(addr, server::Options::default().tls(acceptor));
-//!     let client = SyncClient::connect(addr,
-//!                                      client::Options::default()
-//!                                          .tls(tls::client::Context::new("foobar.com").unwrap()))
-//!                                          .unwrap();
-//!     println!("{}", client.hello("Mom".to_string()).unwrap());
-//! }
-//! ```
-
-#![deny(missing_docs, missing_debug_implementations)]
-#![feature(never_type)]
-#![cfg_attr(test, feature(plugin, use_extern_macros, proc_macro_path_invoc))]
-#![cfg_attr(test, plugin(tarpc_plugins))]
-
-extern crate byteorder;
-extern crate bytes;
-#[macro_use]
-extern crate cfg_if;
-#[macro_use]
-extern crate lazy_static;
-#[macro_use]
-extern crate log;
-extern crate net2;
-extern crate num_cpus;
-extern crate thread_pool;
-extern crate tokio_codec;
-extern crate tokio_io;
-
-#[doc(hidden)]
-pub extern crate bincode;
-#[doc(hidden)]
-#[macro_use]
-pub extern crate futures;
-#[doc(hidden)]
-pub extern crate serde;
-#[doc(hidden)]
-#[macro_use]
-pub extern crate serde_derive;
-#[doc(hidden)]
-pub extern crate tokio_core;
-#[doc(hidden)]
-pub extern crate tokio_proto;
-#[doc(hidden)]
-pub extern crate tokio_service;
-
-pub use errors::Error;
-#[doc(hidden)]
-pub use errors::WireError;
-
-/// Provides some utility error types, as well as a trait for spawning futures on the default event
-/// loop.
-pub mod util;
-
-/// Provides the macro used for constructing rpc services and client stubs.
-#[macro_use]
-mod macros;
-/// Synchronous version of the tarpc API
-pub mod sync;
-/// Futures-based version of the tarpc API.
-pub mod future;
-/// TLS-specific functionality.
-#[cfg(feature = "tls")]
-pub mod tls;
-/// Provides implementations of `ClientProto` and `ServerProto` that implement the tarpc protocol.
-/// The tarpc protocol is a length-delimited, bincode-serialized payload.
-mod protocol;
-/// Provides a few different error types.
-mod errors;
-/// Provides an abstraction over TLS and TCP streams.
-mod stream_type;
-
-use std::sync::mpsc;
-use std::thread;
-use tokio_core::reactor;
-
-lazy_static! {
-    /// The `Remote` for the default reactor core.
-    static ref REMOTE: reactor::Remote = {
-        spawn_core()
-    };
-}
-
-/// Spawns a `reactor::Core` running forever on a new thread.
-fn spawn_core() -> reactor::Remote {
-    let (tx, rx) = mpsc::channel();
-    thread::spawn(move || {
-        let mut core = reactor::Core::new().unwrap();
-        tx.send(core.handle().remote().clone()).unwrap();
-
-        // Run forever
-        core.run(futures::empty::<(), !>()).unwrap();
-    });
-    rx.recv().unwrap()
-}
-
-cfg_if! {
-    if #[cfg(feature = "tls")] {
-        extern crate tokio_tls;
-        extern crate native_tls as native_tls_inner;
-
-        /// Re-exported TLS-related types from the `native_tls` crate.
-        pub mod native_tls {
-            pub use native_tls_inner::{Error, Pkcs12, TlsAcceptor, TlsConnector};
-        }
-    } else {}
-}

src/plugins/src/lib.rs

@@ -1,196 +0,0 @@
-#![feature(plugin_registrar, rustc_private)]
-
-extern crate itertools;
-extern crate rustc_plugin;
-extern crate syntax;
-
-use itertools::Itertools;
-use rustc_plugin::Registry;
-use syntax::ast::{self, Ident, TraitRef, Ty, TyKind};
-use syntax::ext::base::{ExtCtxt, MacResult, DummyResult, MacEager};
-use syntax::codemap::Span;
-use syntax::parse::{self, token, str_lit, PResult};
-use syntax::parse::parser::{Parser, PathStyle};
-use syntax::symbol::Symbol;
-use syntax::ptr::P;
-use syntax::tokenstream::{TokenTree, TokenStream};
-use syntax::util::small_vector::SmallVector;
-
-fn snake_to_camel(cx: &mut ExtCtxt, sp: Span, tts: &[TokenTree]) -> Box<MacResult + 'static> {
-    let mut parser = parse::new_parser_from_tts(cx.parse_sess(), tts.into());
-    // The `expand_expr` method is called so that any macro calls in the
-    // parsed expression are expanded.
-
-    let mut item = match parser.parse_trait_item(&mut false) {
-        Ok(s) => s,
-        Err(mut diagnostic) => {
-            diagnostic.emit();
-            return DummyResult::any(sp);
-        }
-    };
-
-    if let Err(mut diagnostic) = parser.expect(&token::Eof) {
-        diagnostic.emit();
-        return DummyResult::any(sp);
-    }
-
-    let old_ident = convert(&mut item.ident);
-
-    // As far as I know, it's not possible in macro_rules! to reference an $ident in a doc string,
-    // so this is the hacky workaround.
-    //
-    // This code looks intimidating, but it's just iterating through the trait item's attributes
-    // copying non-doc attributes, and modifying doc attributes such that replacing any {} in the
-    // doc string instead holds the original, snake_case ident.
-    let attrs: Vec<_> = item.attrs
-        .drain(..)
-        .map(|mut attr| {
-            if !attr.is_sugared_doc {
-                return attr;
-            }
-
-            // Getting at the underlying doc comment is surprisingly painful.
-            // The call-chain goes something like:
-            //
-            //  - https://github.com/rust-lang/rust/blob/9c15de4fd59bee290848b5443c7e194fd5afb02c/src/libsyntax/attr.rs#L283
-            //  - https://github.com/rust-lang/rust/blob/9c15de4fd59bee290848b5443c7e194fd5afb02c/src/libsyntax/attr.rs#L1067
-            //  - https://github.com/rust-lang/rust/blob/9c15de4fd59bee290848b5443c7e194fd5afb02c/src/libsyntax/attr.rs#L1196
-            //  - https://github.com/rust-lang/rust/blob/9c15de4fd59bee290848b5443c7e194fd5afb02c/src/libsyntax/parse/mod.rs#L399
-            //  - https://github.com/rust-lang/rust/blob/9c15de4fd59bee290848b5443c7e194fd5afb02c/src/libsyntax/parse/mod.rs#L268
-            //
-            // Note that a docstring (i.e., something with is_sugared_doc) *always* has exactly two
-            // tokens: an Eq followed by a Literal, where the Literal contains a Str_. We therefore
-            // match against that, modifying the inner Str with our modified Symbol.
-            let mut tokens = attr.tokens.clone().into_trees();
-            if let Some(tt @ TokenTree::Token(_, token::Eq)) = tokens.next() {
-                let mut docstr = tokens.next().expect("Docstrings must have literal docstring");
-                if let TokenTree::Token(_, token::Literal(token::Str_(ref mut doc), _)) = docstr {
-                    *doc = Symbol::intern(&str_lit(&doc.as_str(), None).replace("{}", &old_ident));
-                } else {
-                    unreachable!();
-                }
-                attr.tokens = TokenStream::concat(vec![tt.into(), docstr.into()]);
-            } else {
-                unreachable!();
-            }
-
-            attr
-        })
-        .collect();
-    item.attrs.extend(attrs.into_iter());
-
-    MacEager::trait_items(SmallVector::one(item))
-}
-
-fn impl_snake_to_camel(cx: &mut ExtCtxt, sp: Span, tts: &[TokenTree]) -> Box<MacResult + 'static> {
-    let mut parser = parse::new_parser_from_tts(cx.parse_sess(), tts.into());
-    // The `expand_expr` method is called so that any macro calls in the
-    // parsed expression are expanded.
-
-    let mut item = match parser.parse_impl_item(&mut false) {
-        Ok(s) => s,
-        Err(mut diagnostic) => {
-            diagnostic.emit();
-            return DummyResult::any(sp);
-        }
-    };
-
-    if let Err(mut diagnostic) = parser.expect(&token::Eof) {
-        diagnostic.emit();
-        return DummyResult::any(sp);
-    }
-
-    convert(&mut item.ident);
-    MacEager::impl_items(SmallVector::one(item))
-}
-
-fn ty_snake_to_camel(cx: &mut ExtCtxt, sp: Span, tts: &[TokenTree]) -> Box<MacResult + 'static> {
-    let mut parser = parse::new_parser_from_tts(cx.parse_sess(), tts.into());
-    // The `expand_expr` method is called so that any macro calls in the
-    // parsed expression are expanded.
-
-    let mut path = match parser.parse_path(PathStyle::Type) {
-        Ok(s) => s,
-        Err(mut diagnostic) => {
-            diagnostic.emit();
-            return DummyResult::any(sp);
-        }
-    };
-
-    if let Err(mut diagnostic) = parser.expect(&token::Eof) {
-        diagnostic.emit();
-        return DummyResult::any(sp);
-    }
-
-    // Only capitalize the final segment
-    convert(&mut path.segments
-                     .last_mut()
-                     .unwrap()
-                     .ident);
-    MacEager::ty(P(Ty {
-        id: ast::DUMMY_NODE_ID,
-        node: TyKind::Path(None, path),
-        span: sp,
-    }))
-}
-
-/// Converts an ident in-place to CamelCase and returns the previous ident.
-fn convert(ident: &mut Ident) -> String {
-    let ident_str = ident.to_string();
-    let mut camel_ty = String::new();
-
-    {
-        // Find the first non-underscore and add it capitalized.
-        let mut chars = ident_str.chars();
-
-        // Find the first non-underscore char, uppercase it, and append it.
-        // Guaranteed to succeed because all idents must have at least one non-underscore char.
-        camel_ty.extend(chars.find(|&c| c != '_').unwrap().to_uppercase());
-
-        // When we find an underscore, we remove it and capitalize the next char. To do this,
-        // we need to ensure the next char is not another underscore.
-        let mut chars = chars.coalesce(|c1, c2| {
-            if c1 == '_' && c2 == '_' {
-                Ok(c1)
-            } else {
-                Err((c1, c2))
-            }
-        });
-
-        while let Some(c) = chars.next() {
-            if c != '_' {
-                camel_ty.push(c);
-            } else if let Some(c) = chars.next() {
-                camel_ty.extend(c.to_uppercase());
-            }
-        }
-    }
-
-    // The Fut suffix is hardcoded right now; this macro isn't really meant to be general-purpose.
-    camel_ty.push_str("Fut");
-
-    *ident = Ident::with_empty_ctxt(Symbol::intern(&camel_ty));
-    ident_str
-}
-
-trait ParseTraitRef {
-    fn parse_trait_ref(&mut self) -> PResult<TraitRef>;
-}
-
-impl<'a> ParseTraitRef for Parser<'a> {
-    /// Parse a::B<String,i32>
-    fn parse_trait_ref(&mut self) -> PResult<TraitRef> {
-        Ok(TraitRef {
-            path: self.parse_path(PathStyle::Type)?,
-            ref_id: ast::DUMMY_NODE_ID,
-        })
-    }
-}
-
-#[plugin_registrar]
-#[doc(hidden)]
-pub fn plugin_registrar(reg: &mut Registry) {
-    reg.register_macro("snake_to_camel", snake_to_camel);
-    reg.register_macro("impl_snake_to_camel", impl_snake_to_camel);
-    reg.register_macro("ty_snake_to_camel", ty_snake_to_camel);
-}

src/protocol.rs

@@ -1,248 +0,0 @@
-// Copyright 2016 Google Inc. All Rights Reserved.
-//
-// Licensed under the MIT License, <LICENSE or http://opensource.org/licenses/MIT>.
-// This file may not be copied, modified, or distributed except according to those terms.
-
-use bincode;
-use byteorder::{BigEndian, ByteOrder};
-use bytes::BytesMut;
-use bytes::buf::BufMut;
-use serde;
-use std::io;
-use std::marker::PhantomData;
-use std::mem;
-use tokio_io::{AsyncRead, AsyncWrite};
-use tokio_codec::{Encoder, Decoder, Framed};
-use tokio_proto::multiplex::{ClientProto, ServerProto};
-use tokio_proto::streaming::multiplex::RequestId;
-
-// `Encode` is the type that `Codec` encodes. `Decode` is the type it decodes.
-#[derive(Debug)]
-pub struct Codec<Encode, Decode> {
-    max_payload_size: u64,
-    state: CodecState,
-    _phantom_data: PhantomData<(Encode, Decode)>,
-}
-
-#[derive(Debug)]
-enum CodecState {
-    Id,
-    Len { id: u64 },
-    Payload { id: u64, len: u64 },
-}
-
-impl<Encode, Decode> Codec<Encode, Decode> {
-    fn new(max_payload_size: u64) -> Self {
-        Codec {
-            max_payload_size,
-            state: CodecState::Id,
-            _phantom_data: PhantomData,
-        }
-    }
-}
-
-fn too_big(payload_size: u64, max_payload_size: u64) -> io::Error {
-    warn!(
-        "Not sending too-big packet of size {} (max is {})",
-        payload_size,
-        max_payload_size
-    );
-    io::Error::new(
-        io::ErrorKind::InvalidData,
-        format!(
-            "Maximum payload size is {} bytes but got a payload of {}",
-            max_payload_size,
-            payload_size
-        ),
-    )
-}
-
-impl<Encode, Decode> Encoder for Codec<Encode, Decode>
-where
-    Encode: serde::Serialize,
-    Decode: serde::de::DeserializeOwned,
-{
-    type Item = (RequestId, Encode);
-    type Error = io::Error;
-
-    fn encode(&mut self, (id, message): Self::Item, buf: &mut BytesMut) -> io::Result<()> {
-        let payload_size = bincode::serialized_size(&message).map_err(|serialize_err| {
-            io::Error::new(io::ErrorKind::Other, serialize_err)
-        })?;
-        if payload_size > self.max_payload_size {
-            return Err(too_big(payload_size, self.max_payload_size));
-        }
-        let message_size = 2 * mem::size_of::<u64>() + payload_size as usize;
-        buf.reserve(message_size);
-        buf.put_u64_be(id);
-        trace!("Encoded request id = {} as {:?}", id, buf);
-        buf.put_u64_be(payload_size);
-        bincode::serialize_into(&mut buf.writer(), &message)
-            .map_err(|serialize_err| {
-                io::Error::new(io::ErrorKind::Other, serialize_err)
-            })?;
-        trace!("Encoded buffer: {:?}", buf);
-        Ok(())
-    }
-}
-
-impl<Encode, Decode> Decoder for Codec<Encode, Decode>
-where
-    Decode: serde::de::DeserializeOwned,
-{
-    type Item = (RequestId, Result<Decode, bincode::Error>);
-    type Error = io::Error;
-
-    fn decode(&mut self, buf: &mut BytesMut) -> io::Result<Option<Self::Item>> {
-        use self::CodecState::*;
-        trace!("Codec::decode: {:?}", buf);
-
-        loop {
-            match self.state {
-                Id if buf.len() < mem::size_of::<u64>() => {
-                    trace!("--> Buf len is {}; waiting for 8 to parse id.", buf.len());
-                    return Ok(None);
-                }
-                Id => {
-                    let mut id_buf = buf.split_to(mem::size_of::<u64>());
-                    let id = BigEndian::read_u64(&*id_buf);
-                    trace!("--> Parsed id = {} from {:?}", id, id_buf);
-                    self.state = Len { id };
-                }
-                Len { .. } if buf.len() < mem::size_of::<u64>() => {
-                    trace!(
-                        "--> Buf len is {}; waiting for 8 to parse packet length.",
-                        buf.len()
-                    );
-                    return Ok(None);
-                }
-                Len { id } => {
-                    let len_buf = buf.split_to(mem::size_of::<u64>());
-                    let len = BigEndian::read_u64(&*len_buf);
-                    trace!(
-                        "--> Parsed payload length = {}, remaining buffer length = {}",
-                        len,
-                        buf.len()
-                    );
-                    if len > self.max_payload_size {
-                        return Err(too_big(len, self.max_payload_size));
-                    }
-                    self.state = Payload { id, len };
-                }
-                Payload { len, .. } if buf.len() < len as usize => {
-                    trace!(
-                        "--> Buf len is {}; waiting for {} to parse payload.",
-                        buf.len(),
-                        len
-                    );
-                    return Ok(None);
-                }
-                Payload { id, len } => {
-                    let payload = buf.split_to(len as usize);
-                    let result = bincode::deserialize(&payload);
-                    // Reset the state machine because, either way, we're done processing this
-                    // message.
-                    self.state = Id;
-
-                    return Ok(Some((id, result)));
-                }
-            }
-        }
-    }
-}
-
-/// Implements the `multiplex::ServerProto` trait.
-#[derive(Debug)]
-pub struct Proto<Encode, Decode> {
-    max_payload_size: u64,
-    _phantom_data: PhantomData<(Encode, Decode)>,
-}
-
-impl<Encode, Decode> Proto<Encode, Decode> {
-    /// Returns a new `Proto`.
-    pub fn new(max_payload_size: u64) -> Self {
-        Proto {
-            max_payload_size: max_payload_size,
-            _phantom_data: PhantomData,
-        }
-    }
-}
-
-impl<T, Encode, Decode> ServerProto<T> for Proto<Encode, Decode>
-where
-    T: AsyncRead + AsyncWrite + 'static,
-    Encode: serde::Serialize + 'static,
-    Decode: serde::de::DeserializeOwned + 'static,
-{
-    type Response = Encode;
-    type Request = Result<Decode, bincode::Error>;
-    type Transport = Framed<T, Codec<Encode, Decode>>;
-    type BindTransport = Result<Self::Transport, io::Error>;
-
-    fn bind_transport(&self, io: T) -> Self::BindTransport {
-        Ok(Framed::new(io, Codec::new(self.max_payload_size)))
-    }
-}
-
-impl<T, Encode, Decode> ClientProto<T> for Proto<Encode, Decode>
-where
-    T: AsyncRead + AsyncWrite + 'static,
-    Encode: serde::Serialize + 'static,
-    Decode: serde::de::DeserializeOwned + 'static,
-{
-    type Response = Result<Decode, bincode::Error>;
-    type Request = Encode;
-    type Transport = Framed<T, Codec<Encode, Decode>>;
-    type BindTransport = Result<Self::Transport, io::Error>;
-
-    fn bind_transport(&self, io: T) -> Self::BindTransport {
-        Ok(Framed::new(io, Codec::new(self.max_payload_size)))
-    }
-}
-
-#[test]
-fn serialize() {
-    const MSG: (u64, (char, char, char)) = (4, ('a', 'b', 'c'));
-    let mut buf = BytesMut::with_capacity(10);
-
-    // Serialize twice to check for idempotence.
-    for _ in 0..2 {
-        let mut codec: Codec<(char, char, char), (char, char, char)> = Codec::new(2_000_000);
-        codec.encode(MSG, &mut buf).unwrap();
-        let actual: Result<
-            Option<(u64, Result<(char, char, char), bincode::Error>)>,
-            io::Error,
-        > = codec.decode(&mut buf);
-
-        match actual {
-            Ok(Some((id, ref v))) if id == MSG.0 && *v.as_ref().unwrap() == MSG.1 => {}
-            bad => panic!("Expected {:?}, but got {:?}", Some(MSG), bad),
-        }
-
-        assert!(buf.is_empty(), "Expected empty buf but got {:?}", buf);
-    }
-}
-
-#[test]
-fn deserialize_big() {
-    let mut codec: Codec<Vec<u8>, Vec<u8>> = Codec::new(24);
-
-    let mut buf = BytesMut::with_capacity(40);
-    assert_eq!(
-        codec
-            .encode((0, vec![0; 24]), &mut buf)
-            .err()
-            .unwrap()
-            .kind(),
-        io::ErrorKind::InvalidData
-    );
-
-    // Header
-    buf.put_slice(&mut [0u8; 8]);
-    // Len
-    buf.put_slice(&mut [0u8, 0, 0, 0, 0, 0, 0, 25]);
-    assert_eq!(
-        codec.decode(&mut buf).err().unwrap().kind(),
-        io::ErrorKind::InvalidData
-    );
-}

src/stream_type.rs

@@ -1,94 +0,0 @@
-use bytes::{Buf, BufMut};
-use futures::Poll;
-use std::io;
-use tokio_core::net::TcpStream;
-use tokio_io::{AsyncRead, AsyncWrite};
-#[cfg(feature = "tls")]
-use tokio_tls::TlsStream;
-
-#[derive(Debug)]
-pub enum StreamType {
-    Tcp(TcpStream),
-    #[cfg(feature = "tls")]
-    Tls(TlsStream<TcpStream>),
-}
-
-impl From<TcpStream> for StreamType {
-    fn from(stream: TcpStream) -> Self {
-        StreamType::Tcp(stream)
-    }
-}
-
-#[cfg(feature = "tls")]
-impl From<TlsStream<TcpStream>> for StreamType {
-    fn from(stream: TlsStream<TcpStream>) -> Self {
-        StreamType::Tls(stream)
-    }
-}
-
-impl io::Read for StreamType {
-    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
-        match *self {
-            StreamType::Tcp(ref mut stream) => stream.read(buf),
-            #[cfg(feature = "tls")]
-            StreamType::Tls(ref mut stream) => stream.read(buf),
-        }
-    }
-}
-
-impl io::Write for StreamType {
-    fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
-        match *self {
-            StreamType::Tcp(ref mut stream) => stream.write(buf),
-            #[cfg(feature = "tls")]
-            StreamType::Tls(ref mut stream) => stream.write(buf),
-        }
-    }
-
-    fn flush(&mut self) -> io::Result<()> {
-        match *self {
-            StreamType::Tcp(ref mut stream) => stream.flush(),
-            #[cfg(feature = "tls")]
-            StreamType::Tls(ref mut stream) => stream.flush(),
-        }
-    }
-}
-
-impl AsyncRead for StreamType {
-    // By overriding this fn, `StreamType` is obliged to never read the uninitialized buffer.
-    // Most sane implementations would never have a reason to, and `StreamType` does not, so
-    // this is safe.
-    unsafe fn prepare_uninitialized_buffer(&self, buf: &mut [u8]) -> bool {
-        match *self {
-            StreamType::Tcp(ref stream) => stream.prepare_uninitialized_buffer(buf),
-            #[cfg(feature = "tls")]
-            StreamType::Tls(ref stream) => stream.prepare_uninitialized_buffer(buf),
-        }
-    }
-
-    fn read_buf<B: BufMut>(&mut self, buf: &mut B) -> Poll<usize, io::Error> {
-        match *self {
-            StreamType::Tcp(ref mut stream) => stream.read_buf(buf),
-            #[cfg(feature = "tls")]
-            StreamType::Tls(ref mut stream) => stream.read_buf(buf),
-        }
-    }
-}
-
-impl AsyncWrite for StreamType {
-    fn shutdown(&mut self) -> Poll<(), io::Error> {
-        match *self {
-            StreamType::Tcp(ref mut stream) => stream.shutdown(),
-            #[cfg(feature = "tls")]
-            StreamType::Tls(ref mut stream) => stream.shutdown(),
-        }
-    }
-
-    fn write_buf<B: Buf>(&mut self, buf: &mut B) -> Poll<usize, io::Error> {
-        match *self {
-            StreamType::Tcp(ref mut stream) => stream.write_buf(buf),
-            #[cfg(feature = "tls")]
-            StreamType::Tls(ref mut stream) => stream.write_buf(buf),
-        }
-    }
-}

src/sync/client.rs

@@ -1,253 +0,0 @@
-use future::client::{Client as FutureClient, ClientExt as FutureClientExt,
-                     Options as FutureOptions};
-use futures::{Future, Stream};
-use serde::Serialize;
-use serde::de::DeserializeOwned;
-use std::fmt;
-use std::io;
-use std::net::{SocketAddr, ToSocketAddrs};
-use std::sync::mpsc;
-use std::thread;
-#[cfg(feature = "tls")]
-use tls::client::Context;
-use tokio_core::reactor;
-use tokio_proto::util::client_proxy::{ClientProxy, Receiver, pair};
-use tokio_service::Service;
-use util::FirstSocketAddr;
-
-#[doc(hidden)]
-pub struct Client<Req, Resp, E> {
-    proxy: ClientProxy<Req, Resp, ::Error<E>>,
-}
-
-impl<Req, Resp, E> Clone for Client<Req, Resp, E> {
-    fn clone(&self) -> Self {
-        Client {
-            proxy: self.proxy.clone(),
-        }
-    }
-}
-
-impl<Req, Resp, E> fmt::Debug for Client<Req, Resp, E> {
-    fn fmt(&self, f: &mut fmt::Formatter) -> Result<(), fmt::Error> {
-        const PROXY: &str = "ClientProxy { .. }";
-        f.debug_struct("Client").field("proxy", &PROXY).finish()
-    }
-}
-
-impl<Req, Resp, E> Client<Req, Resp, E>
-where
-    Req: Serialize + Send + 'static,
-    Resp: DeserializeOwned + Send + 'static,
-    E: DeserializeOwned + Send + 'static,
-{
-    /// Drives an RPC call for the given request.
-    pub fn call(&self, request: Req) -> Result<Resp, ::Error<E>> {
-        // Must call wait here to block on the response.
-        // The request handler relies on this fact to safely unwrap the
-        // oneshot send.
-        self.proxy.call(request).wait()
-    }
-}
-
-/// Additional options to configure how the client connects and operates.
-pub struct Options {
-    /// Max packet size in bytes.
-    max_payload_size: u64,
-    #[cfg(feature = "tls")]
-    tls_ctx: Option<Context>,
-}
-
-impl Default for Options {
-    #[cfg(not(feature = "tls"))]
-    fn default() -> Self {
-        Options {
-            max_payload_size: 2_000_000,
-        }
-    }
-
-    #[cfg(feature = "tls")]
-    fn default() -> Self {
-        Options {
-            max_payload_size: 2_000_000,
-            tls_ctx: None,
-        }
-    }
-}
-
-impl Options {
-    /// Set the max payload size in bytes. The default is 2,000,000 (2 MB).
-    pub fn max_payload_size(mut self, bytes: u64) -> Self {
-        self.max_payload_size = bytes;
-        self
-    }
-
-    /// Connect using the given `Context`
-    #[cfg(feature = "tls")]
-    pub fn tls(mut self, ctx: Context) -> Self {
-        self.tls_ctx = Some(ctx);
-        self
-    }
-}
-
-impl fmt::Debug for Options {
-    fn fmt(&self, f: &mut fmt::Formatter) -> Result<(), fmt::Error> {
-        #[cfg(feature = "tls")]
-        const SOME: &str = "Some(_)";
-        #[cfg(feature = "tls")]
-        const NONE: &str = "None";
-        let mut f = f.debug_struct("Options");
-        #[cfg(feature = "tls")] f.field("tls_ctx", if self.tls_ctx.is_some() { &SOME } else { &NONE });
-        f.finish()
-    }
-}
-
-impl Into<FutureOptions> for (reactor::Handle, Options) {
-    #[cfg(feature = "tls")]
-    fn into(self) -> FutureOptions {
-        let (handle, options) = self;
-        let mut opts = FutureOptions::default().handle(handle);
-        if let Some(tls_ctx) = options.tls_ctx {
-            opts = opts.tls(tls_ctx);
-        }
-        opts
-    }
-
-    #[cfg(not(feature = "tls"))]
-    fn into(self) -> FutureOptions {
-        let (handle, _) = self;
-        FutureOptions::default().handle(handle)
-    }
-}
-
-/// Extension methods for Clients.
-pub trait ClientExt: Sized {
-    /// Connects to a server located at the given address.
-    fn connect<A>(addr: A, options: Options) -> io::Result<Self>
-    where
-        A: ToSocketAddrs;
-}
-
-impl<Req, Resp, E> ClientExt for Client<Req, Resp, E>
-where
-    Req: Serialize + Send + 'static,
-    Resp: DeserializeOwned + Send + 'static,
-    E: DeserializeOwned + Send + 'static,
-{
-    fn connect<A>(addr: A, options: Options) -> io::Result<Self>
-    where
-        A: ToSocketAddrs,
-    {
-        let addr = addr.try_first_socket_addr()?;
-        let (connect_tx, connect_rx) = mpsc::channel();
-        thread::spawn(move || match RequestHandler::connect(addr, options) {
-            Ok((proxy, mut handler)) => {
-                connect_tx.send(Ok(proxy)).unwrap();
-                handler.handle_requests();
-            }
-            Err(e) => connect_tx.send(Err(e)).unwrap(),
-        });
-        Ok(connect_rx.recv().unwrap()?)
-    }
-}
-
-/// Forwards incoming requests of type `Req`
-/// with expected response `Result<Resp, ::Error<E>>`
-/// to service `S`.
-struct RequestHandler<Req, Resp, E, S> {
-    reactor: reactor::Core,
-    client: S,
-    requests: Receiver<Req, Resp, ::Error<E>>,
-}
-
-impl<Req, Resp, E> RequestHandler<Req, Resp, E, FutureClient<Req, Resp, E>>
-where
-    Req: Serialize + Send + 'static,
-    Resp: DeserializeOwned + Send + 'static,
-    E: DeserializeOwned + Send + 'static,
-{
-    /// Creates a new `RequestHandler` by connecting a `FutureClient` to the given address
-    /// using the given options.
-    fn connect(addr: SocketAddr, options: Options) -> io::Result<(Client<Req, Resp, E>, Self)> {
-        let mut reactor = reactor::Core::new()?;
-        let options = (reactor.handle(), options).into();
-        let client = reactor.run(FutureClient::connect(addr, options))?;
-        let (proxy, requests) = pair();
-        Ok((
-            Client { proxy },
-            RequestHandler {
-                reactor,
-                client,
-                requests,
-            },
-        ))
-    }
-}
-
-impl<Req, Resp, E, S> RequestHandler<Req, Resp, E, S>
-where
-    Req: Serialize + 'static,
-    Resp: DeserializeOwned + 'static,
-    E: DeserializeOwned + 'static,
-    S: Service<Request = Req, Response = Resp, Error = ::Error<E>>,
-    S::Future: 'static,
-{
-    fn handle_requests(&mut self) {
-        let RequestHandler {
-            ref mut reactor,
-            ref mut requests,
-            ref mut client,
-        } = *self;
-        let handle = reactor.handle();
-        let requests = requests
-            .map(|result| {
-                match result {
-                    Ok(req) => req,
-                    // The ClientProxy never sends Err currently
-                    Err(e) => panic!("Unimplemented error handling in RequestHandler: {}", e),
-                }
-            })
-            .for_each(|(request, response_tx)| {
-                let request = client.call(request).then(move |response| {
-                    // Safe to unwrap because clients always block on the response future.
-                    response_tx
-                        .send(response)
-                        .map_err(|_| ())
-                        .expect("Client should block on response");
-                    Ok(())
-                });
-                handle.spawn(request);
-                Ok(())
-            });
-        reactor.run(requests).unwrap();
-    }
-}
-
-#[test]
-fn handle_requests() {
-    use futures::future;
-
-    struct Client;
-    impl Service for Client {
-        type Request = i32;
-        type Response = i32;
-        type Error = ::Error<()>;
-        type Future = future::FutureResult<i32, ::Error<()>>;
-
-        fn call(&self, req: i32) -> Self::Future {
-            future::ok(req)
-        }
-    }
-
-    let (request, requests) = ::futures::sync::mpsc::unbounded();
-    let reactor = reactor::Core::new().unwrap();
-    let client = Client;
-    let mut request_handler = RequestHandler {
-        reactor,
-        client,
-        requests,
-    };
-    // Test that `handle_requests` returns when all request senders are dropped.
-    drop(request);
-    request_handler.handle_requests();
-}

src/sync/mod.rs

@@ -1,4 +0,0 @@
-/// Provides the base client stubs used by the service macro.
-pub mod client;
-/// Provides the base server boilerplate used by service implementations.
-pub mod server;

src/sync/server.rs

@@ -1,249 +0,0 @@
-use {bincode, future, num_cpus};
-use future::server::{Response, Shutdown};
-use futures::{Future, future as futures};
-use futures::sync::oneshot;
-#[cfg(feature = "tls")]
-use native_tls_inner::TlsAcceptor;
-use serde::Serialize;
-use serde::de::DeserializeOwned;
-use std::fmt;
-use std::io;
-use std::net::SocketAddr;
-use std::time::Duration;
-use std::usize;
-use thread_pool::{self, Sender, Task, ThreadPool};
-use tokio_core::reactor;
-use tokio_service::{NewService, Service};
-
-/// Additional options to configure how the server operates.
-#[derive(Debug)]
-pub struct Options {
-    thread_pool: thread_pool::Builder,
-    opts: future::server::Options,
-}
-
-impl Default for Options {
-    fn default() -> Self {
-        let num_cpus = num_cpus::get();
-        Options {
-            thread_pool: thread_pool::Builder::new()
-                .keep_alive(Duration::from_secs(60))
-                .max_pool_size(num_cpus * 100)
-                .core_pool_size(num_cpus)
-                .work_queue_capacity(usize::MAX)
-                .name_prefix("request-thread-"),
-            opts: future::server::Options::default(),
-        }
-    }
-}
-
-impl Options {
-    /// Set the max payload size in bytes. The default is 2,000,000 (2 MB).
-    pub fn max_payload_size(mut self, bytes: u64) -> Self {
-        self.opts = self.opts.max_payload_size(bytes);
-        self
-    }
-
-    /// Sets the thread pool builder to use when creating the server's thread pool.
-    pub fn thread_pool(mut self, builder: thread_pool::Builder) -> Self {
-        self.thread_pool = builder;
-        self
-    }
-
-    /// Set the `TlsAcceptor`
-    #[cfg(feature = "tls")]
-    pub fn tls(mut self, tls_acceptor: TlsAcceptor) -> Self {
-        self.opts = self.opts.tls(tls_acceptor);
-        self
-    }
-}
-
-/// A handle to a bound server. Must be run to start serving requests.
-#[must_use = "A server does nothing until `run` is called."]
-pub struct Handle {
-    reactor: reactor::Core,
-    handle: future::server::Handle,
-    server: Box<Future<Item = (), Error = ()>>,
-}
-
-impl Handle {
-    /// Runs the server on the current thread, blocking indefinitely.
-    pub fn run(mut self) {
-        trace!("Running...");
-        match self.reactor.run(self.server) {
-            Ok(()) => debug!("Server successfully shutdown."),
-            Err(()) => debug!("Server shutdown due to error."),
-        }
-    }
-
-    /// Returns a hook for shutting down the server.
-    pub fn shutdown(&self) -> Shutdown {
-        self.handle.shutdown().clone()
-    }
-
-    /// The socket address the server is bound to.
-    pub fn addr(&self) -> SocketAddr {
-        self.handle.addr()
-    }
-}
-
-impl fmt::Debug for Handle {
-    fn fmt(&self, f: &mut fmt::Formatter) -> Result<(), fmt::Error> {
-        const SERVER: &str = "Box<Future<Item = (), Error = ()>>";
-
-        f.debug_struct("Handle")
-            .field("reactor", &self.reactor)
-            .field("handle", &self.handle)
-            .field("server", &SERVER)
-            .finish()
-    }
-}
-
-#[doc(hidden)]
-pub fn listen<S, Req, Resp, E>(new_service: S,
-                               addr: SocketAddr,
-                               options: Options)
-                               -> io::Result<Handle>
-    where S: NewService<Request = Result<Req, bincode::Error>,
-                        Response = Response<Resp, E>,
-                        Error = io::Error> + 'static,
-          <S::Instance as Service>::Future: Send + 'static,
-          S::Response: Send,
-          S::Error: Send,
-          Req: DeserializeOwned + 'static,
-          Resp: Serialize + 'static,
-          E: Serialize + 'static
-{
-    let new_service = NewThreadService::new(new_service, options.thread_pool);
-    let reactor = reactor::Core::new()?;
-    let (handle, server) =
-        future::server::listen(new_service, addr, &reactor.handle(), options.opts)?;
-    let server = Box::new(server);
-    Ok(Handle {
-        reactor: reactor,
-        handle: handle,
-        server: server,
-    })
-}
-
-/// A service that uses a thread pool.
-struct NewThreadService<S>
-where
-    S: NewService,
-{
-    new_service: S,
-    sender: Sender<ServiceTask<<S::Instance as Service>::Future>>,
-    _pool: ThreadPool<ServiceTask<<S::Instance as Service>::Future>>,
-}
-
-/// A service that runs by executing request handlers in a thread pool.
-struct ThreadService<S>
-where
-    S: Service,
-{
-    service: S,
-    sender: Sender<ServiceTask<S::Future>>,
-}
-
-/// A task that handles a single request.
-struct ServiceTask<F>
-where
-    F: Future,
-{
-    future: F,
-    tx: oneshot::Sender<Result<F::Item, F::Error>>,
-}
-
-impl<S> NewThreadService<S>
-where
-    S: NewService,
-    <S::Instance as Service>::Future: Send + 'static,
-    S::Response: Send,
-    S::Error: Send,
-{
-    /// Create a NewThreadService by wrapping another service.
-    fn new(new_service: S, pool: thread_pool::Builder) -> Self {
-        let (sender, _pool) = pool.build();
-        NewThreadService {
-            new_service,
-            sender,
-            _pool,
-        }
-    }
-}
-
-impl<S> NewService for NewThreadService<S>
-where
-    S: NewService,
-    <S::Instance as Service>::Future: Send + 'static,
-    S::Response: Send,
-    S::Error: Send,
-{
-    type Request = S::Request;
-    type Response = S::Response;
-    type Error = S::Error;
-    type Instance = ThreadService<S::Instance>;
-
-    fn new_service(&self) -> io::Result<Self::Instance> {
-        Ok(ThreadService {
-            service: self.new_service.new_service()?,
-            sender: self.sender.clone(),
-        })
-    }
-}
-
-impl<F> Task for ServiceTask<F>
-where
-    F: Future + Send + 'static,
-    F::Item: Send,
-    F::Error: Send,
-{
-    fn run(self) {
-        // Don't care if sending fails. It just means the request is no longer
-        // being handled (I think).
-        let _ = self.tx.send(self.future.wait());
-    }
-}
-
-impl<S> Service for ThreadService<S>
-where
-    S: Service,
-    S::Future: Send + 'static,
-    S::Response: Send,
-    S::Error: Send,
-{
-    type Request = S::Request;
-    type Response = S::Response;
-    type Error = S::Error;
-    type Future = futures::AndThen<
-        futures::MapErr<
-            oneshot::Receiver<Result<Self::Response, Self::Error>>,
-            fn(oneshot::Canceled) -> Self::Error,
-        >,
-        Result<Self::Response, Self::Error>,
-        fn(Result<Self::Response, Self::Error>)
-            -> Result<Self::Response, Self::Error>,
-    >;
-
-    fn call(&self, request: Self::Request) -> Self::Future {
-        let (tx, rx) = oneshot::channel();
-        self.sender
-            .send(ServiceTask {
-                future: self.service.call(request),
-                tx: tx,
-            })
-            .unwrap();
-        rx.map_err(unreachable as _).and_then(ident)
-    }
-}
-
-fn unreachable<T, U>(t: T) -> U
-where
-    T: fmt::Display,
-{
-    unreachable!(t)
-}
-
-fn ident<T>(t: T) -> T {
-    t
-}

src/tls.rs

@@ -1,50 +0,0 @@
-/// TLS-specific functionality for clients.
-pub mod client {
-    use native_tls::{Error, TlsConnector};
-    use std::fmt;
-
-    /// TLS context for client
-    pub struct Context {
-        /// Domain to connect to
-        pub domain: String,
-        /// TLS connector
-        pub tls_connector: TlsConnector,
-    }
-
-    impl Context {
-        /// Try to construct a new `Context`.
-        ///
-        /// The provided domain will be used for both
-        /// [SNI](https://en.wikipedia.org/wiki/Server_Name_Indication) and certificate hostname
-        /// validation.
-        pub fn new<S: Into<String>>(domain: S) -> Result<Self, Error> {
-            Ok(Context {
-                domain: domain.into(),
-                tls_connector: TlsConnector::builder()?.build()?,
-            })
-        }
-
-        /// Construct a new `Context` using the provided domain and `TlsConnector`
-        ///
-        /// The domain will be used for both
-        /// [SNI](https://en.wikipedia.org/wiki/Server_Name_Indication) and certificate hostname
-        /// validation.
-        pub fn from_connector<S: Into<String>>(domain: S, tls_connector: TlsConnector) -> Self {
-            Context {
-                domain: domain.into(),
-                tls_connector: tls_connector,
-            }
-        }
-    }
-
-    impl fmt::Debug for Context {
-        fn fmt(&self, f: &mut fmt::Formatter) -> Result<(), fmt::Error> {
-            const TLS_CONNECTOR: &str = "TlsConnector { .. }";
-            f.debug_struct("Context")
-                .field("domain", &self.domain)
-                .field("tls_connector", &TLS_CONNECTOR)
-                .finish()
-        }
-    }
-
-}

src/util.rs

@@ -1,185 +0,0 @@
-// Copyright 2016 Google Inc. All Rights Reserved.
-//
-// Licensed under the MIT License, <LICENSE or http://opensource.org/licenses/MIT>.
-// This file may not be copied, modified, or distributed except according to those terms.
-
-use futures::{Future, IntoFuture, Poll};
-use futures::stream::Stream;
-use serde::{Deserialize, Deserializer, Serialize, Serializer};
-use std::{fmt, io, mem};
-use std::error::Error;
-use std::net::{SocketAddr, ToSocketAddrs};
-
-/// A bottom type that impls `Error`, `Serialize`, and `Deserialize`. It is impossible to
-/// instantiate this type.
-#[allow(unreachable_code)]
-pub struct Never(!);
-
-impl fmt::Debug for Never {
-    fn fmt(&self, _: &mut fmt::Formatter) -> fmt::Result {
-        self.0
-    }
-}
-
-impl Error for Never {
-    fn description(&self) -> &str {
-        self.0
-    }
-}
-
-impl fmt::Display for Never {
-    fn fmt(&self, _: &mut fmt::Formatter) -> fmt::Result {
-        self.0
-    }
-}
-
-impl Future for Never {
-    type Item = Never;
-    type Error = Never;
-
-    fn poll(&mut self) -> Poll<Self::Item, Self::Error> {
-        self.0
-    }
-}
-
-impl Stream for Never {
-    type Item = Never;
-    type Error = Never;
-
-    fn poll(&mut self) -> Poll<Option<Self::Item>, Self::Error> {
-        self.0
-    }
-}
-
-impl Serialize for Never {
-    fn serialize<S>(&self, _: S) -> Result<S::Ok, S::Error>
-    where
-        S: Serializer,
-    {
-        self.0
-    }
-}
-
-// Please don't try to deserialize this. :(
-impl<'a> Deserialize<'a> for Never {
-    fn deserialize<D>(_: D) -> Result<Self, D::Error>
-    where
-        D: Deserializer<'a>,
-    {
-        panic!("Never cannot be instantiated!");
-    }
-}
-
-/// A `String` that impls `std::error::Error`. Useful for quick-and-dirty error propagation.
-#[derive(Debug, Serialize, Deserialize)]
-pub struct Message(pub String);
-
-impl Error for Message {
-    fn description(&self) -> &str {
-        &self.0
-    }
-}
-
-impl fmt::Display for Message {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        fmt::Display::fmt(&self.0, f)
-    }
-}
-
-impl<S: Into<String>> From<S> for Message {
-    fn from(s: S) -> Self {
-        Message(s.into())
-    }
-}
-
-
-/// Provides a utility method for more ergonomically parsing a `SocketAddr` when only one is
-/// needed.
-pub trait FirstSocketAddr: ToSocketAddrs {
-    /// Returns the first resolved `SocketAddr`, if one exists.
-    fn try_first_socket_addr(&self) -> io::Result<SocketAddr> {
-        if let Some(a) = self.to_socket_addrs()?.next() {
-            Ok(a)
-        } else {
-            Err(io::Error::new(
-                io::ErrorKind::AddrNotAvailable,
-                "`ToSocketAddrs::to_socket_addrs` returned an empty iterator.",
-            ))
-        }
-    }
-
-    /// Returns the first resolved `SocketAddr` or panics otherwise.
-    fn first_socket_addr(&self) -> SocketAddr {
-        self.try_first_socket_addr().unwrap()
-    }
-}
-
-impl<A: ToSocketAddrs> FirstSocketAddr for A {}
-
-/// Creates a new future which will eventually be the same as the one created
-/// by calling the closure provided with the arguments provided.
-///
-/// The provided closure is only run once the future has a callback scheduled
-/// on it, otherwise the callback never runs. Once run, however, this future is
-/// the same as the one the closure creates.
-pub fn lazy<F, A, R>(f: F, args: A) -> Lazy<F, A, R>
-where
-    F: FnOnce(A) -> R,
-    R: IntoFuture,
-{
-    Lazy {
-        inner: _Lazy::First(f, args),
-    }
-}
-
-/// A future which defers creation of the actual future until a callback is
-/// scheduled.
-///
-/// This is created by the `lazy` function.
-#[derive(Debug)]
-#[must_use = "futures do nothing unless polled"]
-pub struct Lazy<F, A, R: IntoFuture> {
-    inner: _Lazy<F, A, R::Future>,
-}
-
-#[derive(Debug)]
-enum _Lazy<F, A, R> {
-    First(F, A),
-    Second(R),
-    Moved,
-}
-
-impl<F, A, R> Lazy<F, A, R>
-where
-    F: FnOnce(A) -> R,
-    R: IntoFuture,
-{
-    fn get(&mut self) -> &mut R::Future {
-        match self.inner {
-            _Lazy::First(..) => {}
-            _Lazy::Second(ref mut f) => return f,
-            _Lazy::Moved => panic!(), // can only happen if `f()` panics
-        }
-        match mem::replace(&mut self.inner, _Lazy::Moved) {
-            _Lazy::First(f, args) => self.inner = _Lazy::Second(f(args).into_future()),
-            _ => panic!(), // we already found First
-        }
-        match self.inner {
-            _Lazy::Second(ref mut f) => f,
-            _ => panic!(), // we just stored Second
-        }
-    }
-}
-
-impl<F, A, R> Future for Lazy<F, A, R>
-where
-    F: FnOnce(A) -> R,
-    R: IntoFuture,
-{
-    type Item = R::Item;
-    type Error = R::Error;
-
-    fn poll(&mut self) -> Poll<R::Item, R::Error> {
-        self.get().poll()
-    }
-}

tarpc/Cargo.toml

@@ -0,0 +1,42 @@
+cargo-features = ["rename-dependency"]
+
+[package]
+name = "tarpc"
+version = "0.14.0"
+authors = ["Adam Wright <adam.austin.wright@gmail.com>", "Tim Kuehn <timothy.j.kuehn@gmail.com>"]
+edition = "2018"
+license = "MIT"
+documentation = "https://docs.rs/tarpc"
+homepage = "https://github.com/google/tarpc"
+repository = "https://github.com/google/tarpc"
+keywords = ["rpc", "network", "server", "api", "microservices"]
+categories = ["asynchronous", "network-programming"]
+readme = "../README.md"
+description = "An RPC framework for Rust with a focus on ease of use."
+
+[features]
+serde1 = ["rpc/serde1", "serde", "serde/derive"]
+
+[badges]
+travis-ci = { repository = "google/tarpc" }
+
+[dependencies]
+log = "0.4"
+serde = { optional = true, version = "1.0" }
+tarpc-plugins = { path = "../plugins", version = "0.5.0" }
+rpc = { package = "tarpc-lib", path = "../rpc", version = "0.2" }
+
+[target.'cfg(not(test))'.dependencies]
+futures-preview = "0.3.0-alpha.9"
+
+[dev-dependencies]
+bincode = "1.0"
+bytes = { version = "0.4", features = ["serde"] }
+humantime = "1.0"
+futures-preview = { version = "0.3.0-alpha.9", features = ["compat", "tokio-compat"] }
+bincode-transport = { package = "tarpc-bincode-transport", version = "0.3", path = "../bincode-transport" }
+env_logger = "0.5"
+tokio = "0.1"
+tokio-executor = "0.1"
+tokio-tcp = "0.1"
+pin-utils = "0.1.0-alpha.3"

tarpc/examples/pubsub.rs

@@ -0,0 +1,185 @@
+// Copyright 2018 Google LLC
+//
+// Use of this source code is governed by an MIT-style
+// license that can be found in the LICENSE file or at
+// https://opensource.org/licenses/MIT.
+
+#![feature(
+    arbitrary_self_types,
+    pin,
+    futures_api,
+    await_macro,
+    async_await,
+    existential_type,
+    proc_macro_hygiene
+)]
+
+use futures::{
+    future::{self, Ready},
+    prelude::*,
+    Future,
+};
+use rpc::{
+    client, context,
+    server::{self, Handler, Server},
+};
+use std::{
+    collections::HashMap,
+    io,
+    net::SocketAddr,
+    sync::{Arc, Mutex},
+    thread,
+    time::Duration,
+};
+
+pub mod subscriber {
+    tarpc::service! {
+        rpc receive(message: String);
+    }
+}
+
+pub mod publisher {
+    use std::net::SocketAddr;
+    tarpc::service! {
+        rpc broadcast(message: String);
+        rpc subscribe(id: u32, address: SocketAddr) -> Result<(), String>;
+        rpc unsubscribe(id: u32);
+    }
+}
+
+#[derive(Clone, Debug)]
+struct Subscriber {
+    id: u32,
+}
+
+impl subscriber::Service for Subscriber {
+    type ReceiveFut = Ready<()>;
+
+    fn receive(self, _: context::Context, message: String) -> Self::ReceiveFut {
+        println!("{} received message: {}", self.id, message);
+        future::ready(())
+    }
+}
+
+impl Subscriber {
+    async fn listen(id: u32, config: server::Config) -> io::Result<SocketAddr> {
+        let incoming = bincode_transport::listen(&"0.0.0.0:0".parse().unwrap())?;
+        let addr = incoming.local_addr();
+        tokio_executor::spawn(
+            server::new(config)
+                .incoming(incoming)
+                .take(1)
+                .respond_with(subscriber::serve(Subscriber { id }))
+                .unit_error()
+                .boxed()
+                .compat(),
+        );
+        Ok(addr)
+    }
+}
+
+#[derive(Clone, Debug)]
+struct Publisher {
+    clients: Arc<Mutex<HashMap<u32, subscriber::Client>>>,
+}
+
+impl Publisher {
+    fn new() -> Publisher {
+        Publisher {
+            clients: Arc::new(Mutex::new(HashMap::new())),
+        }
+    }
+}
+
+impl publisher::Service for Publisher {
+    existential type BroadcastFut: Future<Output = ()>;
+
+    fn broadcast(self, _: context::Context, message: String) -> Self::BroadcastFut {
+        async fn broadcast(clients: Arc<Mutex<HashMap<u32, subscriber::Client>>>, message: String) {
+            let mut clients = clients.lock().unwrap().clone();
+            for client in clients.values_mut() {
+                // Ignore failing subscribers. In a real pubsub,
+                // you'd want to continually retry until subscribers
+                // ack.
+                let _ = await!(client.receive(context::current(), message.clone()));
+            }
+        }
+
+        broadcast(self.clients.clone(), message)
+    }
+
+    existential type SubscribeFut: Future<Output = Result<(), String>>;
+
+    fn subscribe(self, _: context::Context, id: u32, addr: SocketAddr) -> Self::SubscribeFut {
+        async fn subscribe(
+            clients: Arc<Mutex<HashMap<u32, subscriber::Client>>>,
+            id: u32,
+            addr: SocketAddr,
+        ) -> io::Result<()> {
+            let conn = await!(bincode_transport::connect(&addr))?;
+            let subscriber = await!(subscriber::new_stub(client::Config::default(), conn))?;
+            println!("Subscribing {}.", id);
+            clients.lock().unwrap().insert(id, subscriber);
+            Ok(())
+        }
+
+        subscribe(Arc::clone(&self.clients), id, addr).map_err(|e| e.to_string())
+    }
+
+    existential type UnsubscribeFut: Future<Output = ()>;
+
+    fn unsubscribe(self, _: context::Context, id: u32) -> Self::UnsubscribeFut {
+        println!("Unsubscribing {}", id);
+        let mut clients = self.clients.lock().unwrap();
+        if let None = clients.remove(&id) {
+            eprintln!(
+                "Client {} not found. Existings clients: {:?}",
+                id, &*clients
+            );
+        }
+        future::ready(())
+    }
+}
+
+async fn run() -> io::Result<()> {
+    env_logger::init();
+    let transport = bincode_transport::listen(&"0.0.0.0:0".parse().unwrap())?;
+    let publisher_addr = transport.local_addr();
+    tokio_executor::spawn(
+        Server::default()
+            .incoming(transport)
+            .take(1)
+            .respond_with(publisher::serve(Publisher::new()))
+            .unit_error()
+            .boxed()
+            .compat(),
+    );
+
+    let subscriber1 = await!(Subscriber::listen(0, server::Config::default()))?;
+    let subscriber2 = await!(Subscriber::listen(1, server::Config::default()))?;
+
+    let publisher_conn = bincode_transport::connect(&publisher_addr);
+    let publisher_conn = await!(publisher_conn)?;
+    let mut publisher = await!(publisher::new_stub(
+        client::Config::default(),
+        publisher_conn
+    ))?;
+
+    if let Err(e) = await!(publisher.subscribe(context::current(), 0, subscriber1))? {
+        eprintln!("Couldn't subscribe subscriber 0: {}", e);
+    }
+    if let Err(e) = await!(publisher.subscribe(context::current(), 1, subscriber2))? {
+        eprintln!("Couldn't subscribe subscriber 1: {}", e);
+    }
+
+    println!("Broadcasting...");
+    await!(publisher.broadcast(context::current(), "hello to all".to_string()))?;
+    await!(publisher.unsubscribe(context::current(), 1))?;
+    await!(publisher.broadcast(context::current(), "hi again".to_string()))?;
+    Ok(())
+}
+
+fn main() {
+    tokio::run(run().boxed().map_err(|e| panic!(e)).boxed().compat());
+    thread::sleep(Duration::from_millis(100));
+}

tarpc/examples/readme.rs

@@ -0,0 +1,94 @@
+// Copyright 2018 Google LLC
+//
+// Use of this source code is governed by an MIT-style
+// license that can be found in the LICENSE file or at
+// https://opensource.org/licenses/MIT.
+
+#![feature(
+    futures_api,
+    pin,
+    arbitrary_self_types,
+    await_macro,
+    async_await,
+    proc_macro_hygiene
+)]
+
+use futures::{
+    compat::TokioDefaultSpawner,
+    future::{self, Ready},
+    prelude::*,
+};
+use rpc::{
+    client, context,
+    server::{Handler, Server},
+};
+use std::io;
+
+// This is the service definition. It looks a lot like a trait definition.
+// It defines one RPC, hello, which takes one arg, name, and returns a String.
+
+tarpc::service! {
+    rpc hello(name: String) -> String;
+}
+
+// This is the type that implements the generated Service trait. It is the business logic
+// and is used to start the server.
+#[derive(Clone)]
+struct HelloServer;
+
+impl Service for HelloServer {
+    // Each defined rpc generates two items in the trait, a fn that serves the RPC, and
+    // an associated type representing the future output by the fn.
+
+    type HelloFut = Ready<String>;
+
+    fn hello(self, _: context::Context, name: String) -> Self::HelloFut {
+        future::ready(format!("Hello, {}!", name))
+    }
+}
+
+async fn run() -> io::Result<()> {
+    // bincode_transport is provided by the associated crate bincode-transport. It makes it easy
+    // to start up a serde-powered bincode serialization strategy over TCP.
+    let transport = bincode_transport::listen(&"0.0.0.0:0".parse().unwrap())?;
+    let addr = transport.local_addr();
+
+    // The server is configured with the defaults.
+    let server = Server::default()
+        // Server can listen on any type that implements the Transport trait.
+        .incoming(transport)
+        // Close the stream after the client connects
+        .take(1)
+        // serve is generated by the tarpc::service! macro. It takes as input any type implementing
+        // the generated Service trait.
+        .respond_with(serve(HelloServer));
+
+    tokio_executor::spawn(server.unit_error().boxed().compat());
+
+    let transport = await!(bincode_transport::connect(&addr))?;
+
+    // new_stub is generated by the tarpc::service! macro. Like Server, it takes a config and any
+    // Transport as input, and returns a Client, also generated by the macro.
+    // by the service mcro.
+    let mut client = await!(new_stub(client::Config::default(), transport))?;
+
+    // The client has an RPC method for each RPC defined in tarpc::service!. It takes the same args
+    // as defined, with the addition of a Context, which is always the first arg. The Context
+    // specifies a deadline and trace information which can be helpful in debugging requests.
+    let hello = await!(client.hello(context::current(), "Stim".to_string()))?;
+
+    println!("{}", hello);
+
+    Ok(())
+}
+
+fn main() {
+    tarpc::init(TokioDefaultSpawner);
+
+    tokio::run(
+        run()
+            .map_err(|e| eprintln!("Oh no: {}", e))
+            .boxed()
+            .compat(),
+    );
+}

tarpc/examples/server_calling_server.rs

@@ -0,0 +1,108 @@
+// Copyright 2018 Google LLC
+//
+// Use of this source code is governed by an MIT-style
+// license that can be found in the LICENSE file or at
+// https://opensource.org/licenses/MIT.
+
+#![feature(
+    existential_type,
+    arbitrary_self_types,
+    pin,
+    futures_api,
+    await_macro,
+    async_await,
+    proc_macro_hygiene
+)]
+
+use crate::{add::Service as AddService, double::Service as DoubleService};
+use futures::{
+    compat::TokioDefaultSpawner,
+    future::{self, Ready},
+    prelude::*,
+};
+use rpc::{
+    client, context,
+    server::{Handler, Server},
+};
+use std::io;
+
+pub mod add {
+    tarpc::service! {
+        /// Add two ints together.
+        rpc add(x: i32, y: i32) -> i32;
+    }
+}
+
+pub mod double {
+    tarpc::service! {
+        /// 2 * x
+        rpc double(x: i32) -> Result<i32, String>;
+    }
+}
+
+#[derive(Clone)]
+struct AddServer;
+
+impl AddService for AddServer {
+    type AddFut = Ready<i32>;
+
+    fn add(self, _: context::Context, x: i32, y: i32) -> Self::AddFut {
+        future::ready(x + y)
+    }
+}
+
+#[derive(Clone)]
+struct DoubleServer {
+    add_client: add::Client,
+}
+
+impl DoubleService for DoubleServer {
+    existential type DoubleFut: Future<Output = Result<i32, String>> + Send;
+
+    fn double(self, _: context::Context, x: i32) -> Self::DoubleFut {
+        async fn double(mut client: add::Client, x: i32) -> Result<i32, String> {
+            let result = await!(client.add(context::current(), x, x));
+            result.map_err(|e| e.to_string())
+        }
+
+        double(self.add_client.clone(), x)
+    }
+}
+
+async fn run() -> io::Result<()> {
+    let add_listener = bincode_transport::listen(&"0.0.0.0:0".parse().unwrap())?;
+    let addr = add_listener.local_addr();
+    let add_server = Server::default()
+        .incoming(add_listener)
+        .take(1)
+        .respond_with(add::serve(AddServer));
+    tokio_executor::spawn(add_server.unit_error().boxed().compat());
+
+    let to_add_server = await!(bincode_transport::connect(&addr))?;
+    let add_client = await!(add::new_stub(client::Config::default(), to_add_server))?;
+
+    let double_listener = bincode_transport::listen(&"0.0.0.0:0".parse().unwrap())?;
+    let addr = double_listener.local_addr();
+    let double_server = rpc::Server::default()
+        .incoming(double_listener)
+        .take(1)
+        .respond_with(double::serve(DoubleServer { add_client }));
+    tokio_executor::spawn(double_server.unit_error().boxed().compat());
+
+    let to_double_server = await!(bincode_transport::connect(&addr))?;
+    let mut double_client = await!(double::new_stub(
+        client::Config::default(),
+        to_double_server
+    ))?;
+
+    for i in 1..=5 {
+        println!("{:?}", await!(double_client.double(context::current(), i))?);
+    }
+    Ok(())
+}
+
+fn main() {
+    env_logger::init();
+    tarpc::init(TokioDefaultSpawner);
+    tokio::run(run().map_err(|e| panic!(e)).boxed().compat());
+}

tarpc/examples/service_registry.rs

@@ -0,0 +1,411 @@
+#![feature(
+    pin,
+    async_await,
+    await_macro,
+    futures_api,
+    arbitrary_self_types,
+    proc_macro_hygiene,
+    impl_trait_in_bindings
+)]
+
+mod registry {
+    use bytes::Bytes;
+    use futures::{
+        future::{ready, Ready},
+        prelude::*,
+    };
+    use serde::{Deserialize, Serialize};
+    use std::{
+        io,
+        pin::Pin,
+        sync::Arc,
+        task::{LocalWaker, Poll},
+    };
+    use tarpc::{
+        client::{self, Client},
+        context,
+    };
+
+    /// A request to a named service.
+    #[derive(Serialize, Deserialize)]
+    pub struct ServiceRequest {
+        service_name: String,
+        request: Bytes,
+    }
+
+    /// A response from a named service.
+    #[derive(Serialize, Deserialize)]
+    pub struct ServiceResponse {
+        response: Bytes,
+    }
+
+    /// A list of registered services.
+    pub struct Registry<Services> {
+        registrations: Services,
+    }
+
+    impl Default for Registry<Nil> {
+        fn default() -> Self {
+            Registry { registrations: Nil }
+        }
+    }
+
+    impl<Services: MaybeServe + Sync> Registry<Services> {
+        /// Returns a function that serves requests for the registered services.
+        pub fn serve(
+            self,
+        ) -> impl FnOnce(context::Context, ServiceRequest)
+            -> Either<Services::Future, Ready<io::Result<ServiceResponse>>>
+                         + Clone {
+            let registrations = Arc::new(self.registrations);
+            move |cx, req: ServiceRequest| match registrations.serve(cx, &req) {
+                Some(serve) => Either::Left(serve),
+                None => Either::Right(ready(Err(io::Error::new(
+                    io::ErrorKind::NotFound,
+                    format!("Service '{}' not registered", req.service_name),
+                )))),
+            }
+        }
+
+        /// Registers `serve` with the given `name` using the given serialization scheme.
+        pub fn register<S, Req, Resp, RespFut, Ser, De>(
+            self,
+            name: String,
+            serve: S,
+            deserialize: De,
+            serialize: Ser,
+        ) -> Registry<Registration<impl Serve + Send + 'static, Services>>
+        where
+            Req: Send,
+            S: FnOnce(context::Context, Req) -> RespFut + Send + 'static + Clone,
+            RespFut: Future<Output = io::Result<Resp>> + Send + 'static,
+            De: FnOnce(Bytes) -> io::Result<Req> + Send + 'static + Clone,
+            Ser: FnOnce(Resp) -> io::Result<Bytes> + Send + 'static + Clone,
+        {
+            let registrations = Registration {
+                name: name,
+                serve: move |cx, req: Bytes| {
+                    async move {
+                        let req = deserialize.clone()(req)?;
+                        let response = await!(serve.clone()(cx, req))?;
+                        let response = serialize.clone()(response)?;
+                        Ok(ServiceResponse { response })
+                    }
+                },
+                rest: self.registrations,
+            };
+            Registry { registrations }
+        }
+    }
+
+    /// Creates a client that sends requests to a service
+    /// named `service_name`, over the given channel, using
+    /// the specified serialization scheme.
+    pub fn new_client<Req, Resp, Ser, De>(
+        service_name: String,
+        channel: &client::Channel<ServiceRequest, ServiceResponse>,
+        mut serialize: Ser,
+        mut deserialize: De,
+    ) -> client::MapResponse<
+        client::WithRequest<
+            client::Channel<ServiceRequest, ServiceResponse>,
+            impl FnMut(Req) -> ServiceRequest,
+        >,
+        impl FnMut(ServiceResponse) -> Resp,
+    >
+    where
+        Req: Send + 'static,
+        Resp: Send + 'static,
+        De: FnMut(Bytes) -> io::Result<Resp> + Clone + Send + 'static,
+        Ser: FnMut(Req) -> io::Result<Bytes> + Clone + Send + 'static,
+    {
+        channel
+            .clone()
+            .with_request(move |req| {
+                ServiceRequest {
+                    service_name: service_name.clone(),
+                    // TODO: shouldn't need to unwrap here. Maybe with_request should allow for
+                    // returning Result.
+                    request: serialize(req).unwrap(),
+                }
+            })
+            // TODO: same thing. Maybe this should be more like and_then rather than map.
+            .map_response(move |resp| deserialize(resp.response).unwrap())
+    }
+
+    /// Serves a request.
+    ///
+    /// This trait is mostly an implementation detail that isn't used outside of the registry
+    /// internals.
+    pub trait Serve: Clone + Send + 'static {
+        type Response: Future<Output = io::Result<ServiceResponse>> + Send + 'static;
+        fn serve(self, cx: context::Context, request: Bytes) -> Self::Response;
+    }
+
+    /// Serves a request if the request is for a registered service.
+    ///
+    /// This trait is mostly an implementation detail that isn't used outside of the registry
+    /// internals.
+    pub trait MaybeServe: Send + 'static {
+        type Future: Future<Output = io::Result<ServiceResponse>> + Send + 'static;
+
+        fn serve(&self, cx: context::Context, request: &ServiceRequest) -> Option<Self::Future>;
+    }
+
+    /// A registry starting with service S, followed by Rest.
+    ///
+    /// This type is mostly an implementation detail that is not used directly
+    /// outside of the registry internals.
+    pub struct Registration<S, Rest> {
+        /// The registered service's name. Must be unique across all registered services.
+        name: String,
+        /// The registered service.
+        serve: S,
+        /// Any remaining registered services.
+        rest: Rest,
+    }
+
+    /// An empty registry.
+    ///
+    /// This type is mostly an implementation detail that is not used directly
+    /// outside of the registry internals.
+    pub struct Nil;
+
+    impl MaybeServe for Nil {
+        type Future = futures::future::Ready<io::Result<ServiceResponse>>;
+
+        fn serve(&self, _: context::Context, _: &ServiceRequest) -> Option<Self::Future> {
+            None
+        }
+    }
+
+    impl<S, Rest> MaybeServe for Registration<S, Rest>
+    where
+        S: Serve,
+        Rest: MaybeServe,
+    {
+        type Future = Either<S::Response, Rest::Future>;
+
+        fn serve(&self, cx: context::Context, request: &ServiceRequest) -> Option<Self::Future> {
+            if self.name == request.service_name {
+                Some(Either::Left(
+                    self.serve.clone().serve(cx, request.request.clone()),
+                ))
+            } else {
+                self.rest.serve(cx, request).map(Either::Right)
+            }
+        }
+    }
+
+    /// Wraps either of two future types that both resolve to the same output type.
+    #[derive(Debug)]
+    #[must_use = "futures do nothing unless polled"]
+    pub enum Either<Left, Right> {
+        Left(Left),
+        Right(Right),
+    }
+
+    impl<Output, Left, Right> Future for Either<Left, Right>
+    where
+        Left: Future<Output = Output>,
+        Right: Future<Output = Output>,
+    {
+        type Output = Output;
+
+        fn poll(self: Pin<&mut Self>, waker: &LocalWaker) -> Poll<Output> {
+            unsafe {
+                match Pin::get_mut_unchecked(self) {
+                    Either::Left(car) => Pin::new_unchecked(car).poll(waker),
+                    Either::Right(cdr) => Pin::new_unchecked(cdr).poll(waker),
+                }
+            }
+        }
+    }
+
+    impl<Resp, F> Serve for F
+    where
+        F: FnOnce(context::Context, Bytes) -> Resp + Clone + Send + 'static,
+        Resp: Future<Output = io::Result<ServiceResponse>> + Send + 'static,
+    {
+        type Response = Resp;
+
+        fn serve(self, cx: context::Context, request: Bytes) -> Resp {
+            self(cx, request)
+        }
+    }
+}
+
+// Example
+use bytes::Bytes;
+use futures::{
+    future::{ready, Ready},
+    prelude::*,
+};
+use serde::{Deserialize, Serialize};
+use std::{
+    collections::HashMap,
+    io,
+    sync::{Arc, RwLock},
+};
+use tarpc::{client, context, server::Handler};
+
+fn deserialize<Req>(req: Bytes) -> io::Result<Req>
+where
+    Req: for<'a> Deserialize<'a> + Send,
+{
+    bincode::deserialize(req.as_ref()).map_err(|e| io::Error::new(io::ErrorKind::Other, e))
+}
+
+fn serialize<Resp>(resp: Resp) -> io::Result<Bytes>
+where
+    Resp: Serialize,
+{
+    Ok(bincode::serialize(&resp)
+        .map_err(|e| io::Error::new(io::ErrorKind::Other, e))?
+        .into())
+}
+
+mod write_service {
+    tarpc::service! {
+        rpc write(key: String, value: String);
+    }
+}
+
+mod read_service {
+    tarpc::service! {
+        rpc read(key: String) -> Option<String>;
+    }
+}
+
+#[derive(Debug, Default, Clone)]
+struct Server {
+    data: Arc<RwLock<HashMap<String, String>>>,
+}
+
+impl write_service::Service for Server {
+    type WriteFut = Ready<()>;
+
+    fn write(self, _: context::Context, key: String, value: String) -> Self::WriteFut {
+        self.data.write().unwrap().insert(key, value);
+        ready(())
+    }
+}
+
+impl read_service::Service for Server {
+    type ReadFut = Ready<Option<String>>;
+
+    fn read(self, _: context::Context, key: String) -> Self::ReadFut {
+        ready(self.data.read().unwrap().get(&key).cloned())
+    }
+}
+
+trait DefaultSpawn {
+    fn spawn(self);
+}
+
+impl<F> DefaultSpawn for F
+where
+    F: Future<Output = ()> + Send + 'static,
+{
+    fn spawn(self) {
+        tokio_executor::spawn(self.unit_error().boxed().compat())
+    }
+}
+
+struct BincodeRegistry<Services> {
+    registry: registry::Registry<Services>,
+}
+
+impl Default for BincodeRegistry<registry::Nil> {
+    fn default() -> Self {
+        BincodeRegistry {
+            registry: registry::Registry::default(),
+        }
+    }
+}
+
+impl<Services: registry::MaybeServe + Sync> BincodeRegistry<Services> {
+    fn serve(
+        self,
+    ) -> impl FnOnce(
+        context::Context, registry::ServiceRequest
+    ) -> registry::Either<
+        Services::Future,
+        Ready<io::Result<registry::ServiceResponse>>,
+    > + Clone {
+        self.registry.serve()
+    }
+
+    fn register<S, Req, Resp, RespFut>(
+        self,
+        name: String,
+        serve: S,
+    ) -> BincodeRegistry<registry::Registration<impl registry::Serve + Send + 'static, Services>>
+    where
+        Req: for<'a> Deserialize<'a> + Send + 'static,
+        Resp: Serialize + 'static,
+        S: FnOnce(context::Context, Req) -> RespFut + Send + 'static + Clone,
+        RespFut: Future<Output = io::Result<Resp>> + Send + 'static,
+    {
+        let registry = self.registry.register(name, serve, deserialize, serialize);
+        BincodeRegistry { registry }
+    }
+}
+
+pub fn new_client<Req, Resp>(
+    service_name: String,
+    channel: &client::Channel<registry::ServiceRequest, registry::ServiceResponse>,
+) -> client::MapResponse<
+    client::WithRequest<
+        client::Channel<registry::ServiceRequest, registry::ServiceResponse>,
+        impl FnMut(Req) -> registry::ServiceRequest,
+    >,
+    impl FnMut(registry::ServiceResponse) -> Resp,
+>
+where
+    Req: Serialize + Send + 'static,
+    Resp: for<'a> Deserialize<'a> + Send + 'static,
+{
+    registry::new_client(service_name, channel, serialize, deserialize)
+}
+
+async fn run() -> io::Result<()> {
+    let server = Server::default();
+    let registry = BincodeRegistry::default()
+        .register(
+            "WriteService".to_string(),
+            write_service::serve(server.clone()),
+        )
+        .register(
+            "ReadService".to_string(),
+            read_service::serve(server.clone()),
+        );
+
+    let listener = bincode_transport::listen(&"0.0.0.0:0".parse().unwrap())?;
+    let server_addr = listener.local_addr();
+    let server = tarpc::Server::default()
+        .incoming(listener)
+        .take(1)
+        .respond_with(registry.serve());
+    tokio_executor::spawn(server.unit_error().boxed().compat());
+
+    let transport = await!(bincode_transport::connect(&server_addr))?;
+    let channel = await!(client::new(client::Config::default(), transport))?;
+
+    let write_client = new_client("WriteService".to_string(), &channel);
+    let mut write_client = write_service::Client::from(write_client);
+
+    let read_client = new_client("ReadService".to_string(), &channel);
+    let mut read_client = read_service::Client::from(read_client);
+
+    await!(write_client.write(context::current(), "key".to_string(), "val".to_string()))?;
+    let val = await!(read_client.read(context::current(), "key".to_string()))?;
+    println!("{:?}", val);
+
+    Ok(())
+}
+
+fn main() {
+    tarpc::init(futures::compat::TokioDefaultSpawner);
+    tokio::run(run().boxed().map_err(|e| panic!(e)).boxed().compat());
+}

tarpc/rustfmt.toml

@@ -0,0 +1 @@
+edition = "2018"

tarpc/src/lib.rs

@@ -0,0 +1,169 @@
+// Copyright 2018 Google LLC
+//
+// Use of this source code is governed by an MIT-style
+// license that can be found in the LICENSE file or at
+// https://opensource.org/licenses/MIT.
+
+//! ## tarpc: Tim & Adam's RPC lib
+//! [![Travis-CI Status](https://travis-ci.org/google/tarpc.png?branch=master)](https://travis-ci.org/google/tarpc)
+//! [![Coverage Status](https://coveralls.io/repos/github/google/tarpc/badge.svg?branch=master)](https://coveralls.io/github/google/tarpc?branch=master)
+//! [![Software License](https://img.shields.io/badge/license-MIT-brightgreen.svg)](LICENSE)
+//! [![Latest Version](https://img.shields.io/crates/v/tarpc.svg)](https://crates.io/crates/tarpc)
+//! [![Join the chat at https://gitter.im/tarpc/Lobby](https://badges.gitter.im/tarpc/Lobby.svg)](https://gitter.im/tarpc/Lobby?utm_source=badge&utm_medium=badge&utm_campaign=pr-badge&utm_content=badge)
+//!
+//! *Disclaimer*: This is not an official Google product.
+//!
+//! tarpc is an RPC framework for rust with a focus on ease of use. Defining a
+//! service can be done in just a few lines of code, and most of the boilerplate of
+//! writing a server is taken care of for you.
+//!
+//! [Documentation](https://docs.rs/crate/tarpc/)
+//!
+//! ## What is an RPC framework?
+//! "RPC" stands for "Remote Procedure Call," a function call where the work of
+//! producing the return value is being done somewhere else. When an rpc function is
+//! invoked, behind the scenes the function contacts some other process somewhere
+//! and asks them to evaluate the function instead. The original function then
+//! returns the value produced by the other process.
+//!
+//! RPC frameworks are a fundamental building block of most microservices-oriented
+//! architectures. Two well-known ones are [gRPC](http://www.grpc.io) and
+//! [Cap'n Proto](https://capnproto.org/).
+//!
+//! tarpc differentiates itself from other RPC frameworks by defining the schema in code,
+//! rather than in a separate language such as .proto. This means there's no separate compilation
+//! process, and no cognitive context switching between different languages. Additionally, it
+//! works with the community-backed library serde: any serde-serializable type can be used as
+//! arguments to tarpc fns.
+//!
+//! ## Usage
+//! Add to your `Cargo.toml` dependencies:
+//!
+//! ```toml
+//! tarpc = "0.14.0"
+//! ```
+//!
+//! The `service!` macro expands to a collection of items that form an
+//! rpc service. In the above example, the macro is called within the
+//! `hello_service` module. This module will contain a `Client` stub and `Service` trait.  There is
+//! These generated types make it easy and ergonomic to write servers without dealing with serialization
+//! directly. Simply implement one of the generated traits, and you're off to the
+//! races!
+//!
+//! ## Example
+//!
+//! Here's a small service.
+//!
+//! ```rust
+//! #![feature(futures_api, pin, arbitrary_self_types, await_macro, async_await, proc_macro_hygiene)]
+//!
+//!
+//! use futures::{
+//!     compat::TokioDefaultSpawner,
+//!     future::{self, Ready},
+//!     prelude::*,
+//! };
+//! use tarpc::{
+//!     client, context,
+//!     server::{self, Handler},
+//! };
+//! use std::io;
+//!
+//! // This is the service definition. It looks a lot like a trait definition.
+//! // It defines one RPC, hello, which takes one arg, name, and returns a String.
+//! tarpc::service! {
+//!     /// Returns a greeting for name.
+//!     rpc hello(name: String) -> String;
+//! }
+//!
+//! // This is the type that implements the generated Service trait. It is the business logic
+//! // and is used to start the server.
+//! #[derive(Clone)]
+//! struct HelloServer;
+//!
+//! impl Service for HelloServer {
+//!     // Each defined rpc generates two items in the trait, a fn that serves the RPC, and
+//!     // an associated type representing the future output by the fn.
+//!
+//!     type HelloFut = Ready<String>;
+//!
+//!     fn hello(self, _: context::Context, name: String) -> Self::HelloFut {
+//!         future::ready(format!("Hello, {}!", name))
+//!     }
+//! }
+//!
+//! async fn run() -> io::Result<()> {
+//!     // bincode_transport is provided by the associated crate bincode-transport. It makes it easy
+//!     // to start up a serde-powered bincode serialization strategy over TCP.
+//!     let transport = bincode_transport::listen(&"0.0.0.0:0".parse().unwrap())?;
+//!     let addr = transport.local_addr();
+//!
+//!     // The server is configured with the defaults.
+//!     let server = server::new(server::Config::default())
+//!         // Server can listen on any type that implements the Transport trait.
+//!         .incoming(transport)
+//!         // Close the stream after the client connects
+//!         .take(1)
+//!         // serve is generated by the service! macro. It takes as input any type implementing
+//!         // the generated Service trait.
+//!         .respond_with(serve(HelloServer));
+//!
+//!     tokio_executor::spawn(server.unit_error().boxed().compat());
+//!
+//!     let transport = await!(bincode_transport::connect(&addr))?;
+//!
+//!     // new_stub is generated by the service! macro. Like Server, it takes a config and any
+//!     // Transport as input, and returns a Client, also generated by the macro.
+//!     // by the service mcro.
+//!     let mut client = await!(new_stub(client::Config::default(), transport))?;
+//!
+//!     // The client has an RPC method for each RPC defined in service!. It takes the same args
+//!     // as defined, with the addition of a Context, which is always the first arg. The Context
+//!     // specifies a deadline and trace information which can be helpful in debugging requests.
+//!     let hello = await!(client.hello(context::current(), "Stim".to_string()))?;
+//!
+//!     println!("{}", hello);
+//!
+//!     Ok(())
+//! }
+//!
+//! fn main() {
+//!     tarpc::init(TokioDefaultSpawner);
+//!     tokio::run(run()
+//!             .map_err(|e| eprintln!("Oh no: {}", e))
+//!             .boxed()
+//!             .compat(),
+//!     );
+//! }
+//! ```
+//!
+//! ## Service Documentation
+//!
+//! Use `cargo doc` as you normally would to see the documentation created for all
+//! items expanded by a `service!` invocation.
+
+#![deny(missing_docs, missing_debug_implementations)]
+#![feature(async_await)]
+#![cfg_attr(
+    test,
+    feature(
+        pin,
+        futures_api,
+        await_macro,
+        proc_macro_hygiene,
+        arbitrary_self_types
+    )
+)]
+
+#[doc(hidden)]
+pub use futures;
+pub use rpc::*;
+#[cfg(feature = "serde")]
+#[doc(hidden)]
+pub use serde;
+#[doc(hidden)]
+pub use tarpc_plugins::*;
+
+/// Provides the macro used for constructing rpc services and client stubs.
+#[macro_use]
+mod macros;

tarpc/src/macros.rs

@@ -0,0 +1,377 @@
+// Copyright 2018 Google LLC
+//
+// Use of this source code is governed by an MIT-style
+// license that can be found in the LICENSE file or at
+// https://opensource.org/licenses/MIT.
+
+#[cfg(feature = "serde")]
+#[doc(hidden)]
+#[macro_export]
+macro_rules! add_serde_if_enabled {
+    ($(#[$attr:meta])* -- $i:item) => {
+        $(#[$attr])*
+        #[derive($crate::serde::Serialize, $crate::serde::Deserialize)]
+        $i
+    }
+}
+
+#[cfg(not(feature = "serde"))]
+#[doc(hidden)]
+#[macro_export]
+macro_rules! add_serde_if_enabled {
+    ($(#[$attr:meta])* -- $i:item) => {
+        $(#[$attr])*
+        $i
+    }
+}
+
+/// The main macro that creates RPC services.
+///
+/// Rpc methods are specified, mirroring trait syntax:
+///
+/// ```
+/// # #![feature(await_macro, pin, arbitrary_self_types, async_await, futures_api, proc_macro_hygiene)]
+/// # fn main() {}
+/// # tarpc::service! {
+/// /// Say hello
+/// rpc hello(name: String) -> String;
+/// # }
+/// ```
+///
+/// Attributes can be attached to each rpc. These attributes
+/// will then be attached to the generated service traits'
+/// corresponding `fn`s, as well as to the client stubs' RPCs.
+///
+/// The following items are expanded in the enclosing module:
+///
+/// * `trait Service` -- defines the RPC service.
+///   * `fn serve` -- turns a service impl into a request handler.
+/// * `Client` -- a client stub with a fn for each RPC.
+///   * `fn new_stub` -- creates a new Client stub.
+///
+#[macro_export]
+macro_rules! service {
+    () => {
+        compile_error!("Must define at least one RPC method.");
+    };
+// Entry point
+    (
+        $(
+            $(#[$attr:meta])*
+            rpc $fn_name:ident( $( $arg:ident : $in_:ty ),* ) $(-> $out:ty)*;
+        )*
+    ) => {
+        $crate::service! {{
+            $(
+                $(#[$attr])*
+                rpc $fn_name( $( $arg : $in_ ),* ) $(-> $out)*;
+            )*
+        }}
+    };
+// Pattern for when the next rpc has an implicit unit return type.
+    (
+        {
+            $(#[$attr:meta])*
+            rpc $fn_name:ident( $( $arg:ident : $in_:ty ),* );
+
+            $( $unexpanded:tt )*
+        }
+        $( $expanded:tt )*
+    ) => {
+        $crate::service! {
+            { $( $unexpanded )* }
+
+            $( $expanded )*
+
+            $(#[$attr])*
+            rpc $fn_name( $( $arg : $in_ ),* ) -> ();
+        }
+    };
+// Pattern for when the next rpc has an explicit return type.
+    (
+        {
+            $(#[$attr:meta])*
+            rpc $fn_name:ident( $( $arg:ident : $in_:ty ),* ) -> $out:ty;
+
+            $( $unexpanded:tt )*
+        }
+        $( $expanded:tt )*
+    ) => {
+        $crate::service! {
+            { $( $unexpanded )* }
+
+            $( $expanded )*
+
+            $(#[$attr])*
+            rpc $fn_name( $( $arg : $in_ ),* ) -> $out;
+        }
+    };
+// Pattern for when all return types have been expanded
+    (
+        { } // none left to expand
+        $(
+            $(#[$attr:meta])*
+            rpc $fn_name:ident ( $( $arg:ident : $in_:ty ),* ) -> $out:ty;
+        )*
+    ) => {
+        $crate::add_serde_if_enabled! {
+            /// The request sent over the wire from the client to the server.
+            #[derive(Debug)]
+            #[allow(non_camel_case_types, unused)]
+            --
+            pub enum Request {
+                $(
+                    $(#[$attr])*
+                    $fn_name{ $($arg: $in_,)* }
+                ),*
+            }
+        }
+
+        $crate::add_serde_if_enabled! {
+            /// The response sent over the wire from the server to the client.
+            #[derive(Debug)]
+            #[allow(non_camel_case_types, unused)]
+            --
+            pub enum Response {
+                $(
+                    $(#[$attr])*
+                    $fn_name($out)
+                ),*
+            }
+        }
+
+        // TODO: proc_macro can't currently parse $crate, so this needs to be imported for the
+        // usage of snake_to_camel! to work.
+        use $crate::futures::Future as Future__;
+
+        /// Defines the RPC service. The additional trait bounds are required so that services can
+        /// multiplex requests across multiple tasks, potentially on multiple threads.
+        pub trait Service: Clone + Send + 'static {
+            $(
+                $crate::snake_to_camel! {
+                    /// The type of future returned by `{}`.
+                    type $fn_name: Future__<Output = $out> + Send;
+                }
+
+                $(#[$attr])*
+                fn $fn_name(self, ctx: $crate::context::Context, $($arg:$in_),*) -> $crate::ty_snake_to_camel!(Self::$fn_name);
+            )*
+        }
+
+        // TODO: use an existential type instead of this when existential types work.
+        /// A future resolving to a server [`Response`].
+        #[allow(non_camel_case_types)]
+        pub enum ResponseFut<S: Service> {
+            $(
+                $(#[$attr])*
+                $fn_name($crate::ty_snake_to_camel!(<S as Service>::$fn_name)),
+            )*
+        }
+
+        impl<S: Service> ::std::fmt::Debug for ResponseFut<S> {
+            fn fmt(&self, fmt: &mut ::std::fmt::Formatter) -> ::std::fmt::Result {
+                fmt.debug_struct("Response").finish()
+            }
+        }
+
+        impl<S: Service> ::std::future::Future for ResponseFut<S> {
+            type Output = ::std::io::Result<Response>;
+
+            fn poll(self: ::std::pin::Pin<&mut Self>, waker: &::std::task::LocalWaker)
+                -> ::std::task::Poll<::std::io::Result<Response>>
+            {
+                unsafe {
+                    match ::std::pin::Pin::get_mut_unchecked(self) {
+                        $(
+                            ResponseFut::$fn_name(resp) =>
+                                ::std::pin::Pin::new_unchecked(resp)
+                                    .poll(waker)
+                                    .map(Response::$fn_name)
+                                    .map(Ok),
+                        )*
+                    }
+                }
+            }
+        }
+
+        /// Returns a serving function to use with rpc::server::Server.
+        pub fn serve<S: Service>(service: S)
+            -> impl FnOnce($crate::context::Context, Request) -> ResponseFut<S> + Send + 'static + Clone {
+                move |ctx, req| {
+                    match req {
+                        $(
+                            Request::$fn_name{ $($arg,)* } => {
+                                let resp = Service::$fn_name(service.clone(), ctx, $($arg),*);
+                                ResponseFut::$fn_name(resp)
+                            }
+                        )*
+                    }
+                }
+            }
+
+        #[allow(unused)]
+        #[derive(Clone, Debug)]
+        /// The client stub that makes RPC calls to the server. Exposes a Future interface.
+        pub struct Client<C = $crate::client::Channel<Request, Response>>(C);
+
+        /// Returns a new client stub that sends requests over the given transport.
+        pub async fn new_stub<T>(config: $crate::client::Config, transport: T)
+            -> ::std::io::Result<Client>
+        where
+            T: $crate::Transport<
+                    Item = $crate::Response<Response>,
+                    SinkItem = $crate::ClientMessage<Request>> + Send + 'static,
+        {
+            Ok(Client(await!($crate::client::new(config, transport))?))
+        }
+
+        impl<C> From<C> for Client<C>
+            where for <'a> C: $crate::Client<'a, Request, Response = Response>
+        {
+            fn from(client: C) -> Self {
+                Client(client)
+            }
+        }
+
+        impl<C> Client<C>
+            where for<'a> C: $crate::Client<'a, Request, Response = Response>
+        {
+            $(
+                #[allow(unused)]
+                $(#[$attr])*
+                pub fn $fn_name(&mut self, ctx: $crate::context::Context, $($arg: $in_),*)
+                    -> impl ::std::future::Future<Output = ::std::io::Result<$out>> + '_ {
+                    let request__ = Request::$fn_name { $($arg,)* };
+                    let resp = $crate::Client::call(&mut self.0, ctx, request__);
+                    async move {
+                        match await!(resp)? {
+                            Response::$fn_name(msg__) => ::std::result::Result::Ok(msg__),
+                            _ => unreachable!(),
+                        }
+                    }
+                }
+            )*
+        }
+    }
+}
+
+// allow dead code; we're just testing that the macro expansion compiles
+#[allow(dead_code)]
+#[cfg(test)]
+mod syntax_test {
+    service! {
+        #[deny(warnings)]
+        #[allow(non_snake_case)]
+        rpc TestCamelCaseDoesntConflict();
+        rpc hello() -> String;
+        #[doc="attr"]
+        rpc attr(s: String) -> String;
+        rpc no_args_no_return();
+        rpc no_args() -> ();
+        rpc one_arg(foo: String) -> i32;
+        rpc two_args_no_return(bar: String, baz: u64);
+        rpc two_args(bar: String, baz: u64) -> String;
+        rpc no_args_ret_error() -> i32;
+        rpc one_arg_ret_error(foo: String) -> String;
+        rpc no_arg_implicit_return_error();
+        #[doc="attr"]
+        rpc one_arg_implicit_return_error(foo: String);
+    }
+}
+
+#[cfg(test)]
+mod functional_test {
+    use futures::{
+        compat::TokioDefaultSpawner,
+        future::{ready, Ready},
+        prelude::*,
+    };
+    use rpc::{client, context, server::Handler, transport::channel};
+    use std::io;
+    use tokio::runtime::current_thread;
+
+    service! {
+        rpc add(x: i32, y: i32) -> i32;
+        rpc hey(name: String) -> String;
+    }
+
+    #[derive(Clone)]
+    struct Server;
+
+    impl Service for Server {
+        type AddFut = Ready<i32>;
+
+        fn add(self, _: context::Context, x: i32, y: i32) -> Self::AddFut {
+            ready(x + y)
+        }
+
+        type HeyFut = Ready<String>;
+
+        fn hey(self, _: context::Context, name: String) -> Self::HeyFut {
+            ready(format!("Hey, {}.", name))
+        }
+    }
+
+    #[test]
+    fn sequential() {
+        let _ = env_logger::try_init();
+        rpc::init(TokioDefaultSpawner);
+
+        let test = async {
+            let (tx, rx) = channel::unbounded();
+            tokio_executor::spawn(
+                crate::Server::default()
+                    .incoming(stream::once(ready(Ok(rx))))
+                    .respond_with(serve(Server))
+                    .unit_error()
+                    .boxed()
+                    .compat(),
+            );
+
+            let mut client = await!(new_stub(client::Config::default(), tx))?;
+            assert_eq!(3, await!(client.add(context::current(), 1, 2))?);
+            assert_eq!(
+                "Hey, Tim.",
+                await!(client.hey(context::current(), "Tim".to_string()))?
+            );
+            Ok::<_, io::Error>(())
+        }
+            .map_err(|e| panic!(e.to_string()));
+
+        current_thread::block_on_all(test.boxed().compat()).unwrap();
+    }
+
+    #[test]
+    fn concurrent() {
+        let _ = env_logger::try_init();
+        rpc::init(TokioDefaultSpawner);
+
+        let test = async {
+            let (tx, rx) = channel::unbounded();
+            tokio_executor::spawn(
+                rpc::Server::default()
+                    .incoming(stream::once(ready(Ok(rx))))
+                    .respond_with(serve(Server))
+                    .unit_error()
+                    .boxed()
+                    .compat(),
+            );
+
+            let client = await!(new_stub(client::Config::default(), tx))?;
+            let mut c = client.clone();
+            let req1 = c.add(context::current(), 1, 2);
+            let mut c = client.clone();
+            let req2 = c.add(context::current(), 3, 4);
+            let mut c = client.clone();
+            let req3 = c.hey(context::current(), "Tim".to_string());
+
+            assert_eq!(3, await!(req1)?);
+            assert_eq!(7, await!(req2)?);
+            assert_eq!("Hey, Tim.", await!(req3)?);
+            Ok::<_, io::Error>(())
+        }
+            .map_err(|e| panic!("test failed: {}", e));
+
+        current_thread::block_on_all(test.boxed().compat()).unwrap();
+    }
+}

tarpc/tests/latency.rs

@@ -0,0 +1,126 @@
+// Copyright 2018 Google LLC
+//
+// Use of this source code is governed by an MIT-style
+// license that can be found in the LICENSE file or at
+// https://opensource.org/licenses/MIT.
+
+#![feature(
+    test,
+    arbitrary_self_types,
+    pin,
+    integer_atomics,
+    futures_api,
+    generators,
+    await_macro,
+    async_await,
+    proc_macro_hygiene
+)]
+
+extern crate test;
+
+use self::test::stats::Stats;
+use futures::{compat::TokioDefaultSpawner, future, prelude::*};
+use rpc::{
+    client, context,
+    server::{Handler, Server},
+};
+use std::{
+    io,
+    time::{Duration, Instant},
+};
+
+mod ack {
+    tarpc::service! {
+        rpc ack();
+    }
+}
+
+#[derive(Clone)]
+struct Serve;
+
+impl ack::Service for Serve {
+    type AckFut = future::Ready<()>;
+
+    fn ack(self, _: context::Context) -> Self::AckFut {
+        future::ready(())
+    }
+}
+
+async fn bench() -> io::Result<()> {
+    let listener = bincode_transport::listen(&"0.0.0.0:0".parse().unwrap())?;
+    let addr = listener.local_addr();
+
+    tokio_executor::spawn(
+        Server::default()
+            .incoming(listener)
+            .take(1)
+            .respond_with(ack::serve(Serve))
+            .unit_error()
+            .boxed()
+            .compat(),
+    );
+
+    let conn = await!(bincode_transport::connect(&addr))?;
+    let mut client = await!(ack::new_stub(client::Config::default(), conn))?;
+
+    let total = 10_000usize;
+    let mut successful = 0u32;
+    let mut unsuccessful = 0u32;
+    let mut durations = vec![];
+    for _ in 1..=total {
+        let now = Instant::now();
+        let response = await!(client.ack(context::current()));
+        let elapsed = now.elapsed();
+
+        match response {
+            Ok(_) => successful += 1,
+            Err(_) => unsuccessful += 1,
+        };
+        durations.push(elapsed);
+    }
+
+    let durations_nanos = durations
+        .iter()
+        .map(|duration| duration.as_secs() as f64 * 1E9 + duration.subsec_nanos() as f64)
+        .collect::<Vec<_>>();
+
+    let (lower, median, upper) = durations_nanos.quartiles();
+
+    println!("Of {:?} runs:", durations_nanos.len());
+    println!("\tSuccessful: {:?}", successful);
+    println!("\tUnsuccessful: {:?}", unsuccessful);
+    println!(
+        "\tMean: {:?}",
+        Duration::from_nanos(durations_nanos.mean() as u64)
+    );
+    println!("\tMedian: {:?}", Duration::from_nanos(median as u64));
+    println!(
+        "\tStd Dev: {:?}",
+        Duration::from_nanos(durations_nanos.std_dev() as u64)
+    );
+    println!(
+        "\tMin: {:?}",
+        Duration::from_nanos(durations_nanos.min() as u64)
+    );
+    println!(
+        "\tMax: {:?}",
+        Duration::from_nanos(durations_nanos.max() as u64)
+    );
+    println!(
+        "\tQuartiles: ({:?}, {:?}, {:?})",
+        Duration::from_nanos(lower as u64),
+        Duration::from_nanos(median as u64),
+        Duration::from_nanos(upper as u64)
+    );
+
+    println!("done");
+    Ok(())
+}
+
+#[test]
+fn bench_small_packet() {
+    env_logger::init();
+    tarpc::init(TokioDefaultSpawner);
+
+    tokio::run(bench().map_err(|e| panic!(e.to_string())).boxed().compat())
+}

test/root-ca.pem

@@ -1,21 +0,0 @@
------BEGIN CERTIFICATE-----
-MIIDXTCCAkWgAwIBAgIJAOIvDiVb18eVMA0GCSqGSIb3DQEBCwUAMEUxCzAJBgNV
-BAYTAkFVMRMwEQYDVQQIDApTb21lLVN0YXRlMSEwHwYDVQQKDBhJbnRlcm5ldCBX
-aWRnaXRzIFB0eSBMdGQwHhcNMTYwODE0MTY1NjExWhcNMjYwODEyMTY1NjExWjBF
-MQswCQYDVQQGEwJBVTETMBEGA1UECAwKU29tZS1TdGF0ZTEhMB8GA1UECgwYSW50
-ZXJuZXQgV2lkZ2l0cyBQdHkgTHRkMIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIB
-CgKCAQEArVHWFn52Lbl1l59exduZntVSZyDYpzDND+S2LUcO6fRBWhV/1Kzox+2G
-ZptbuMGmfI3iAnb0CFT4uC3kBkQQlXonGATSVyaFTFR+jq/lc0SP+9Bd7SBXieIV
-eIXlY1TvlwIvj3Ntw9zX+scTA4SXxH6M0rKv9gTOub2vCMSHeF16X8DQr4XsZuQr
-7Cp7j1I4aqOJyap5JTl5ijmG8cnu0n+8UcRlBzy99dLWJG0AfI3VRJdWpGTNVZ92
-aFff3RpK3F/WI2gp3qV1ynRAKuvmncGC3LDvYfcc2dgsc1N6Ffq8GIrkgRob6eBc
-klDHp1d023Lwre+VaVDSo1//Y72UFwIDAQABo1AwTjAdBgNVHQ4EFgQUbNOlA6sN
-XyzJjYqciKeId7g3/ZowHwYDVR0jBBgwFoAUbNOlA6sNXyzJjYqciKeId7g3/Zow
-DAYDVR0TBAUwAwEB/zANBgkqhkiG9w0BAQsFAAOCAQEAVVaR5QWLZIRR4Dw6TSBn
-BQiLpBSXN6oAxdDw6n4PtwW6CzydaA+creiK6LfwEsiifUfQe9f+T+TBSpdIYtMv
-Z2H2tjlFX8VrjUFvPrvn5c28CuLI0foBgY8XGSkR2YMYzWw2jPEq3Th/KM5Catn3
-AFm3bGKWMtGPR4v+90chEN0jzaAmJYRrVUh9vea27bOCn31Nse6XXQPmSI6Gyncy
-OAPUsvPClF3IjeL1tmBotWqSGn1cYxLo+Lwjk22A9h6vjcNQRyZF2VLVvtwYrNU3
-mwJ6GCLsLHpwW/yjyvn8iEltnJvByM/eeRnfXV6WDObyiZsE/n6DxIRJodQzFqy9
-GA==
------END CERTIFICATE-----

trace/Cargo.toml

@@ -0,0 +1,21 @@
+[package]
+name = "tarpc-trace"
+version = "0.1.0"
+authors = ["tikue <tikue@google.com>"]
+edition = '2018'
+license = "MIT"
+documentation = "https://docs.rs/tarpc-trace"
+homepage = "https://github.com/google/tarpc"
+repository = "https://github.com/google/tarpc"
+keywords = ["rpc", "network", "server", "api", "tls"]
+categories = ["asynchronous", "network-programming"]
+readme = "../README.md"
+description = "foundations for tracing in tarpc"
+
+[dependencies]
+rand = "0.5"
+
+[dependencies.serde]
+version = "1.0"
+optional = true
+features = ["derive"]

trace/rustfmt.toml

@@ -0,0 +1 @@
+edition = "2018"

trace/src/lib.rs

@@ -0,0 +1,106 @@
+// Copyright 2018 Google LLC
+//
+// Use of this source code is governed by an MIT-style
+// license that can be found in the LICENSE file or at
+// https://opensource.org/licenses/MIT.
+
+#![deny(missing_docs, missing_debug_implementations)]
+
+//! Provides building blocks for tracing distributed programs.
+//!
+//! A trace is logically a tree of causally-related events called spans. Traces are tracked via a
+//! [context](Context) that identifies the current trace, span, and parent of the current span.  In
+//! distributed systems, a context can be sent from client to server to connect events occurring on
+//! either side.
+//!
+//! This crate's design is based on [opencensus
+//! tracing](https://opencensus.io/core-concepts/tracing/).
+
+use rand::Rng;
+use std::{
+    fmt::{self, Formatter},
+    mem,
+};
+
+/// A context for tracing the execution of processes, distributed or otherwise.
+///
+/// Consists of a span identifying an event, an optional parent span identifying a causal event
+/// that triggered the current span, and a trace with which all related spans are associated.
+#[derive(Debug, PartialEq, Eq, Hash, Clone, Copy)]
+#[cfg_attr(
+    feature = "serde",
+    derive(serde::Serialize, serde::Deserialize)
+)]
+pub struct Context {
+    /// An identifier of the trace associated with the current context. A trace ID is typically
+    /// created at a root span and passed along through all causal events.
+    pub trace_id: TraceId,
+    /// An identifier of the current span. In typical RPC usage, a span is created by a client
+    /// before making an RPC, and the span ID is sent to the server. The server is free to create
+    /// its own spans, for which it sets the client's span as the parent span.
+    pub span_id: SpanId,
+    /// An identifier of the span that originated the current span. For example, if a server sends
+    /// an RPC in response to a client request that included a span, the server would create a span
+    /// for the RPC and set its parent to the span_id in the incoming request's context.
+    ///
+    /// If `parent_id` is `None`, then this is a root context.
+    pub parent_id: Option<SpanId>,
+}
+
+/// A 128-bit UUID identifying a trace. All spans caused by the same originating span share the
+/// same trace ID.
+#[derive(Debug, PartialEq, Eq, Hash, Clone, Copy)]
+#[cfg_attr(
+    feature = "serde",
+    derive(serde::Serialize, serde::Deserialize)
+)]
+pub struct TraceId(u128);
+
+/// A 64-bit identifier of a span within a trace. The identifier is unique within the span's trace.
+#[derive(Debug, PartialEq, Eq, Hash, Clone, Copy)]
+#[cfg_attr(
+    feature = "serde",
+    derive(serde::Serialize, serde::Deserialize)
+)]
+pub struct SpanId(u64);
+
+impl Context {
+    /// Constructs a new root context. A root context is one with no parent span.
+    pub fn new_root() -> Self {
+        let rng = &mut rand::thread_rng();
+        Context {
+            trace_id: TraceId::random(rng),
+            span_id: SpanId::random(rng),
+            parent_id: None,
+        }
+    }
+}
+
+impl TraceId {
+    /// Returns a random trace ID that can be assumed to be globally unique if `rng` generates
+    /// actually-random numbers.
+    pub fn random<R: Rng>(rng: &mut R) -> Self {
+        TraceId((rng.next_u64() as u128) << mem::size_of::<u64>() | rng.next_u64() as u128)
+    }
+}
+
+impl SpanId {
+    /// Returns a random span ID that can be assumed to be unique within a single trace.
+    pub fn random<R: Rng>(rng: &mut R) -> Self {
+        SpanId(rng.next_u64())
+    }
+}
+
+impl fmt::Display for TraceId {
+    fn fmt(&self, f: &mut Formatter) -> Result<(), fmt::Error> {
+        write!(f, "{:02x}", self.0)?;
+        Ok(())
+    }
+}
+
+impl fmt::Display for SpanId {
+    fn fmt(&self, f: &mut Formatter) -> Result<(), fmt::Error> {
+        write!(f, "{:02x}", self.0)?;
+        Ok(())
+    }
+}