Bump to v0.16.0

* Use upstream sink compat shims
* Port to new Sink trait introduced in e101c891f04aba34ee29c6a8cd8321563c7e0161
* rustfmt
* Port to std::task::Context
* Add Google license header to bincode-transport/src/compat.rs
* Remove compat for it is no longer needed
* future::join as freestanding function
* Simplify dependencies
* Depend on futures-preview 0.3.0-alpha.14
* Fix infinite recursion

.gitignore

@@ -1,3 +1,7 @@
 target
 Cargo.lock
+.cargo
 *.swp
+*.bk
+tarpc.iml
+.idea

.travis.yml

@@ -1,32 +1,13 @@
 language: rust
-sudo: false
-
 rust:
-    - stable
-    - beta
     - nightly
+sudo: false
+cache: cargo
 
-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
+os:
+    - osx
+    - linux
 
 script:
-- |
-    (cd tarpc && travis-cargo build) &&
-    (cd tarpc && travis-cargo test)
-
-after_success:
-- (cd tarpc && 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

@@ -0,0 +1,10 @@
+[workspace]
+
+members = [
+    "example-service",
+    "rpc",
+    "trace",
+    "bincode-transport",
+    "tarpc",
+    "plugins",
+]

README.md

@@ -1,90 +1,136 @@
 ## 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.txt)
+[![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.
+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://google.github.io/tarpc)
+[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 compute the function instead. The original
-function then returns the value produced by that other server.
+"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.
 
-[More information](https://www.cs.cf.ac.uk/Dave/C/node33.html)
+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 = "0.3.0"
+tarpc = "0.15.0"
 ```
 
-## Example
-```rust
-#[macro_use]
-extern crate tarpc;
+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!
 
-mod hello_service {
-    service! {
-        rpc hello(name: String) -> String;
+## Example
+
+Here's a small service.
+
+```rust
+#![feature(futures_api, pin, arbitrary_self_types, await_macro, async_await, proc_macro_hygiene)]
+
+
+use futures::{
+    compat::Executor01CompatExt,
+    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))
     }
 }
-use hello_service::Service as HelloService;
 
-struct HelloServer;
-impl HelloService for HelloServer {
-    fn hello(&self, name: String) -> String {
-        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() {
-    let server_handle = HelloServer.spawn("0.0.0.0:0").unwrap();
-    let client = hello_service::Client::new(server_handle.local_addr()).unwrap();
-    assert_eq!("Hello, Mom!", client.hello("Mom".into()).unwrap());
-    drop(client);
-    server_handle.shutdown();
+    tarpc::init(tokio::executor::DefaultExecutor::current().compat());
+    tokio::run(run()
+            .map_err(|e| eprintln!("Oh no: {}", e))
+            .boxed()
+            .compat(),
+    );
 }
 ```
 
-The `service!` macro expands to a collection of items that collectively form an rpc service. In the
-above example, the macro is called within the `hello_service` module. This module will contain a
-`Client` (and `AsyncClient`) type, and a `Service` trait. The trait provides `default fn`s for
-starting the service: `spawn` and `spawn_with_config`, which start the service listening on a tcp
-port. A `Client` (or `AsyncClient`) can connect to such a service. These generated types make it
-easy and ergonomic to write servers without dealing with sockets or serialization directly. See the
-tarpc_examples package for more sophisticated examples.
+## Service Documentation
 
-## 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.
-- Any type that `impl`s `serde`'s `Serialize` and `Deserialize` can be used in the rpc signatures.
-- Attributes can be specified on rpc methods. These will be included on both the `Service` trait
-  methods as well as on the `Client`'s stub methods.
-- Just like regular fns, the return type can be left off when it's `-> ()`.
-- Arg-less rpc's are also allowed.
-
-## Planned Improvements (actively being worked on)
-- Automatically reconnect on the client side when the connection cuts out.
-- Support asynchronous server implementations (currently thread per connection).
-- 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

@@ -1,4 +1,113 @@
-## 1.3 (2016-02-20)
+## 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
+Fixed rustc breakage in tarpc-plugins. These changes require a recent version of rustc.
+
+## 0.10.0 (2018-03-26)
+
+### Breaking Changes
+Updates bincode to version 1.0.
+
+## 0.9.0 (2017-09-17)
+
+### Breaking Changes
+Updates tarpc to use tarpc-plugins 0.2.
+
+## 0.8.0 (2017-05-05)
+
+### 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)
+detail migration paths.
+
+## 0.7.3 (2017-04-26)
+
+This release removes the `Sync` bound on RPC args for both sync and future
+clients. No breaking changes.
+
+## 0.7.2 (2017-04-22)
+
+### 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.
+
+## 0.7.1 (2017-03-31)
+
+This release was purely doc fixes. No breaking changes.
+
+## 0.7 (2017-03-31)
+
+### 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.
+
+Two traits are now generated by the macro, `FutureService` and `SyncService`.
+`SyncService` is the successor to the original `Service` trait. It uses a configurable
+thread pool to serve requests. `FutureService`, as the name implies, uses futures
+to serve requests and is single-threaded by default.
+
+The easiest way to upgrade from a 0.6 service impl is to `impl SyncService for MyService`.
+For more complete information, see the readme and the examples directory.
+
+## 0.6 (2016-08-07)
+
+### Breaking Changes
+* Updated serde to 0.8. Requires dependents to update as well.
+
+## 0.5 (2016-04-24)
+
+### Breaking Changes
+0.5 adds support for arbitrary transports via the
+[`Transport`](tarpc/src/transport/mod.rs#L7) trait.
+Out of the box tarpc provides implementations for:
+
+* Tcp, for types `impl`ing `ToSocketAddrs`.
+* Unix sockets via the `UnixTransport` type.
+
+This was a breaking change: `handler.local_addr()` was renamed
+`handler.dialer()`.
+
+## 0.4 (2016-04-02)
+
+### Breaking Changes
+* Updated to the latest version of serde, 0.7.0. Because tarpc exposes serde in
+  its API, this forces downstream code to update to the latest version of
+  serde, as well.
+
+## 0.3 (2016-02-20)
 
 ### Breaking Changes
 * The timeout arg to `serve` was replaced with a `Config` struct, which

bincode-transport/Cargo.toml

@@ -0,0 +1,36 @@
+[package]
+name = "tarpc-bincode-transport"
+version = "0.5.0"
+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 = "1"
+futures-preview = { version = "0.3.0-alpha.14", features = ["compat"] }
+futures_legacy = { version = "0.1", package = "futures" }
+pin-utils = "0.1.0-alpha.4"
+rpc = { package = "tarpc-lib", version = "0.4", path = "../rpc", features = ["serde1"] }
+serde = "1.0"
+tokio-io = "0.1"
+async-bincode = "0.4"
+tokio-tcp = "0.1"
+
+[dev-dependencies]
+env_logger = "0.6"
+humantime = "1.0"
+libtest = "0.0.1"
+log = "0.4"
+rand = "0.6"
+tokio = "0.1"
+tokio-executor = "0.1"
+tokio-reactor = "0.1"
+tokio-serde = "0.3"
+tokio-timer = "0.2"

bincode-transport/rustfmt.toml

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

bincode-transport/src/lib.rs

@@ -0,0 +1,181 @@
+// 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, arbitrary_self_types, await_macro, async_await)]
+#![deny(missing_docs, missing_debug_implementations)]
+
+use async_bincode::{AsyncBincodeStream, AsyncDestination};
+use futures::{compat::*, prelude::*, ready};
+use pin_utils::unsafe_pinned;
+use serde::{Deserialize, Serialize};
+use std::{
+    error::Error,
+    io,
+    marker::PhantomData,
+    net::SocketAddr,
+    pin::Pin,
+    task::{Context, Poll},
+};
+use tokio_io::{AsyncRead, AsyncWrite};
+use tokio_tcp::{TcpListener, TcpStream};
+
+/// A transport that serializes to, and deserializes from, a [`TcpStream`].
+#[derive(Debug)]
+pub struct Transport<S, Item, SinkItem> {
+    inner: Compat01As03Sink<AsyncBincodeStream<S, Item, SinkItem, AsyncDestination>, SinkItem>,
+}
+
+impl<S, Item, SinkItem> Transport<S, Item, SinkItem> {
+    unsafe_pinned!(
+        inner: Compat01As03Sink<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(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<io::Result<Item>>> {
+        match self.inner().poll_next(cx) {
+            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<SinkItem> for Transport<S, Item, SinkItem>
+where
+    S: AsyncWrite,
+    SinkItem: Serialize,
+{
+    type SinkError = io::Error;
+
+    fn start_send(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(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<io::Result<()>> {
+        convert(self.inner().poll_ready(cx))
+    }
+
+    fn poll_flush(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<io::Result<()>> {
+        convert(self.inner().poll_flush(cx))
+    }
+
+    fn poll_close(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<io::Result<()>> {
+        convert(self.inner().poll_close(cx))
+    }
+}
+
+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: Compat01As03Sink::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(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<Self::Item>> {
+        let next = ready!(self.incoming().poll_next(cx)?);
+        Poll::Ready(next.map(|conn| Ok(new(conn))))
+    }
+}

bincode-transport/tests/bench.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.
+
+//! Tests client/server control flow.
+
+#![feature(
+    test,
+    integer_atomics,
+    futures_api,
+    generators,
+    await_macro,
+    async_await
+)]
+
+use futures::{compat::Executor01CompatExt, prelude::*};
+use libtest::stats::Stats;
+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(tokio::executor::DefaultExecutor::current().compat());
+
+    tokio::run(bench().map_err(|e| panic!(e.to_string())).boxed().compat());
+    println!("done");
+
+    Ok(())
+}

bincode-transport/tests/cancel.rs

@@ -0,0 +1,146 @@
+// 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::{Executor01CompatExt, Future01CompatExt},
+    prelude::*,
+    stream::FuturesUnordered,
+};
+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!(requests
+        .into_iter()
+        .collect::<FuturesUnordered<_>>()
+        .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(tokio::executor::DefaultExecutor::current().compat());
+
+    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::{Executor01CompatExt, Future01CompatExt},
+    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(tokio::executor::DefaultExecutor::current().compat());
+
+    tokio::run(
+        run()
+            .map_ok(|_| println!("done"))
+            .map_err(|e| panic!(e.to_string()))
+            .boxed()
+            .compat(),
+    );
+
+    Ok(())
+}

example-service/Cargo.toml

@@ -0,0 +1,34 @@
+[package]
+name = "tarpc-example-service"
+version = "0.4.0"
+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 = "0.5", path = "../bincode-transport" }
+clap = "2.0"
+futures-preview = { version = "0.3.0-alpha.14", features = ["compat"] }
+serde = { version = "1.0" }
+tarpc = { version = "0.16", 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 +1,73 @@
+// 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, arbitrary_self_types, await_macro, async_await)]
+
+use clap::{App, Arg};
+use futures::{compat::Executor01CompatExt, 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(tokio::executor::DefaultExecutor::current().compat());
+
+    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(tokio::executor::DefaultExecutor::current().compat());
+
+    tokio::run(
+        run(server_addr, name.into())
+            .map_err(|e| eprintln!("Oh no: {}", e))
+            .boxed()
+            .compat(),
+    );
+}

example-service/src/lib.rs

@@ -0,0 +1,20 @@
+// 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,
+    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 +1,84 @@
+// 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, arbitrary_self_types, await_macro, async_await)]
+
+use clap::{App, Arg};
+use futures::{
+    compat::Executor01CompatExt,
+    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(tokio::executor::DefaultExecutor::current().compat());
+
+    tokio::run(
+        run(([0, 0, 0, 0], port).into())
+            .map_err(|e| eprintln!("Oh no: {}", e))
+            .boxed()
+            .compat(),
+    );
+}

hooks/pre-commit

@@ -67,7 +67,7 @@ else
 fi
 
 printf "${PREFIX} Checking for rustfmt ... "
-command -v rustfmt &>/dev/null
+command -v cargo fmt &>/dev/null
 if [ $? == 0 ]; then
 	printf "${SUCCESS}\n"
 else
@@ -89,22 +89,23 @@ fi
 # not only contain discrete files.
 printf "${PREFIX} Checking formatting ... "
 FMTRESULT=0
+diff=""
 for file in $(git diff --name-only --cached);
 do
 	if [ ${file: -3} == ".rs" ]; then
-        diff=$(rustfmt --skip-children --write-mode=diff $file)
-        if grep --quiet "^Diff at line" <<< "$diff"; then
-			FMTRESULT=1
-		fi
+        diff="$diff$(cargo fmt -- --skip-children --write-mode=diff $file)"
 	fi
 done
+if grep --quiet "^[-+]" <<< "$diff"; then
+    FMTRESULT=1
+fi
 
 if [ "${TARPC_SKIP_RUSTFMT}" == 1 ]; then
 	printf "${SKIPPED}\n"$?
 elif [ ${FMTRESULT} != 0 ]; then
 	FAILED=1
 	printf "${FAILURE}\n"
-    echo "$diff" | sed '/Using rustfmt.*$/d'
+    echo "$diff" | sed 's/Using rustfmt config file.*$/d/'
 else
 	printf "${SUCCESS}\n"
 fi

hooks/pre-push

@@ -8,7 +8,7 @@
 # Pre-push hook for the tarpc repository. To use this hook, copy it to .git/hooks in your repository
 # root.
 #
-# This hook runs tests to make sure only working code is being pushed. If present, multirust is used
+# This hook runs tests to make sure only working code is being pushed. If present, rustup is used
 # to build and test the code on the appropriate toolchains. The working copy must not contain
 # uncommitted changes, since the script currently just runs cargo build/test in the working copy.
 #
@@ -20,11 +20,6 @@
 #   copy. Set to 0 by default, since the intent is to test the code that's being pushed, not changes
 #   still in the working copy.
 #
-# - TARPC_USE_CURRENT_TOOLCHAIN, default = 0
-#
-#   Setting this variable to 1 will just run cargo build and cargo test, rather than running
-#   stable/beta/nightly.
-#
 # Note that these options are most useful for testing the hooks themselves. Use git push --no-verify
 # to skip the pre-push hook altogether.
 
@@ -42,86 +37,62 @@ SUCCESS="${GREEN}ok${NC}"
 printf "${PREFIX} Clean working copy ... "
 git diff --exit-code &>/dev/null
 if [ "$?" == 0 ]; then
-	printf "${SUCCESS}\n"
+    printf "${SUCCESS}\n"
 else
-	if [ "${TARPC_ALLOW_DIRTY}" == "1" ]
-	then
-		printf "${SKIPPED}\n"
-	else
-		printf "${FAILURE}\n"
-		exit 1
-	fi
+    if [ "${TARPC_ALLOW_DIRTY}" == "1" ]
+    then
+        printf "${SKIPPED}\n"
+    else
+        printf "${FAILURE}\n"
+        exit 1
+    fi
 fi
 
 PREPUSH_RESULT=0
 
-# args:
-# 1 - cargo command to run (build/test)
-# 2 - directory name of crate to build
-# 3 - rust toolchain (nightly/stable/beta)
-run_cargo() {
-	if [ "$1" == "build" ]; then
-		VERB=Building
-	else
-		VERB=Testing
-	fi
-	if [ "$3" != "" ]; then
-		printf "${PREFIX} $VERB $2 on $3 ... "
-		multirust run $3 cargo $1 --manifest-path $2/Cargo.toml &>/dev/null
-	else
-		printf "${PREFIX} $VERB $2 ... "
-		cargo $1 --manifest-path $2/Cargo.toml &>/dev/null
-	fi
-	if [ "$?" != "0" ]; then
-		printf "${FAILURE}\n"
+try_run() {
+    TEXT=$1
+    shift
+    printf "${PREFIX} ${TEXT}"
+    OUTPUT=$($@ 2>&1)
+    if [ "$?" != "0" ]; then
+        printf "${FAILURE}, output shown below\n"
+        printf "\n\n"
+        printf "$OUTPUT"
+        printf "\n\n"
 		PREPUSH_RESULT=1
-	else
-		printf "${SUCCESS}\n"
-	fi
+        return 1
+    else
+        printf "${SUCCESS}\n"
+    fi
 }
 
 TOOLCHAIN_RESULT=0
 check_toolchain() {
-	printf "${PREFIX} Checking for $1 toolchain ... "
-	if [[ $(multirust list-toolchain) =~ $1 ]]; then
-		printf "${SUCCESS}\n"
-	else
-		TOOLCHAIN_RESULT=1
-		PREPUSH_RESULT=1
-		printf "${FAILURE}\n"
-	fi
+    printf "${PREFIX} Checking for $1 toolchain ... "
+    if [[ $(rustup toolchain list) =~ $1 ]]; then
+        printf "${SUCCESS}\n"
+    else
+        TOOLCHAIN_RESULT=1
+        PREPUSH_RESULT=1
+        printf "${FAILURE}\n"
+    fi
 }
 
-printf "${PREFIX} Checking for multirust ... "
-command -v multirust &>/dev/null
-if [ "$?" == 0 ] && [ "${TARPC_USE_CURRENT_TOOLCHAIN}" == "" ]; then
-	printf "${SUCCESS}\n"
+printf "${PREFIX} Checking for rustup or current toolchain directive... "
+command -v rustup &>/dev/null
+if [ "$?" == 0 ]; then
+    printf "${SUCCESS}\n"
 
-	check_toolchain stable
-	check_toolchain beta
-	check_toolchain nightly
-	if [ ${TOOLCHAIN_RESULT} == 1 ]; then
-		exit 1
-	fi
+    check_toolchain nightly
+    if [ ${TOOLCHAIN_RESULT} == 1 ]; then
+        exit 1
+    fi
 
-	run_cargo build tarpc stable
-	run_cargo build tarpc_examples stable
+    try_run "Building ... " cargo build --color=always
+    try_run "Testing ... " cargo test --color=always
+    try_run "Doc Test ... " cargo clean && cargo build --tests && rustdoc --test README.md --edition 2018 -L target/debug/deps -Z unstable-options
 
-	run_cargo build tarpc beta
-	run_cargo build tarpc_examples beta
-
-	run_cargo build tarpc nightly
-	run_cargo build tarpc_examples nightly
-
-	# We still rely on some nightly stuff for tests
-	run_cargo test tarpc nightly
-	run_cargo test tarpc_examples nightly
-else
-	printf "${YELLOW}NOT FOUND${NC}\n"
-	printf "${WARNING} Falling back to current toolchain: $(rustc -V)\n"
-
-	run_cargo test tarpc
-	run_cargo test tarpc_examples
 fi
 
 exit $PREPUSH_RESULT

plugins/Cargo.toml

@@ -0,0 +1,24 @@
+[package]
+name = "tarpc-plugins"
+version = "0.5.1"
+authors = ["Adam Wright <adam.austin.wright@gmail.com>", "Tim Kuehn <timothy.j.kuehn@gmail.com>"]
+license = "MIT"
+documentation = "https://docs.rs/tarpc-plugins"
+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 = "Proc macros for tarpc."
+
+[badges]
+travis-ci = { repository = "google/tarpc" }
+
+[dependencies]
+itertools = "0.8"
+syn = { version = "0.15", features = ["full", "extra-traits"] }
+quote = "0.6"
+proc-macro2 = "0.4"
+
+[lib]
+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 +1,33 @@
+[package]
+name = "tarpc-lib"
+version = "0.4.0"
+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"
+futures-preview = { version = "0.3.0-alpha.14", features = ["compat"] }
+humantime = "1.0"
+log = "0.4"
+pin-utils = "0.1.0-alpha.4"
+rand = "0.6"
+tokio-timer = "0.2"
+trace = { package = "tarpc-trace", version = "0.2", path = "../trace" }
+serde = { optional = true, version = "1.0" }
+
+[dev-dependencies]
+futures-test-preview = { version = "0.3.0-alpha.14" }
+env_logger = "0.6"
+tokio = "0.1"

rpc/rustfmt.toml

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

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 +1,189 @@
+// 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,
+    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::{Poll, 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
+    }
+}
+
+pub(crate) type PollIo<T> = Poll<Option<io::Result<T>>>;
+
+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.as_ref().expect("init() must be called.").box_clone())
+        }
+    };
+}
+
+/// 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<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 +1,266 @@
+// 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, PollIo, Response, Transport,
+};
+use fnv::FnvHashMap;
+use futures::{
+    channel::mpsc,
+    prelude::*,
+    ready,
+    stream::Fuse,
+    task::{Context, 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.as_mut().open_connections();
+        if open_connections >= self.as_mut().config().max_connections {
+            warn!(
+                "[{}] Shedding connection because the maximum open connections \
+                 limit is reached ({}/{}).",
+                peer,
+                open_connections,
+                self.as_mut().config().max_connections
+            );
+            return NewConnection::Filtered;
+        }
+
+        let config = self.config.clone();
+        let open_connections_for_ip = self.increment_connections_for_ip(&peer)?;
+        *self.as_mut().open_connections() += 1;
+
+        debug!(
+            "[{}] Opening channel ({}/{} connections for IP, {} total).",
+            peer,
+            open_connections_for_ip,
+            config.max_connections_per_ip,
+            self.as_mut().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.as_mut().open_connections() -= 1;
+        debug!(
+            "[{}] Closing channel. {} open connections remaining.",
+            addr, self.open_connections
+        );
+        self.decrement_connections_for_ip(&addr);
+        self.as_mut().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.as_mut().config().max_connections_per_ip;
+        let mut occupied;
+        let mut connections_per_ip = self.as_mut().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.as_mut().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.as_mut().connections_per_ip().compact(0.1);
+        }
+    }
+
+    fn poll_listener<C>(
+        mut self: Pin<&mut Self>,
+        cx: &mut Context<'_>,
+    ) -> PollIo<NewConnection<Req, Resp, C>>
+    where
+        S: Stream<Item = Result<C, io::Error>>,
+        C: Transport<Item = ClientMessage<Req>, SinkItem = Response<Resp>> + Send,
+    {
+        match ready!(self.as_mut().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: &mut Context<'_>,
+    ) -> Poll<io::Result<()>> {
+        match ready!(self.as_mut().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: &mut Context<'_>) -> PollIo<Channel<Req, Resp, T>> {
+        loop {
+            match (
+                self.as_mut().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.as_mut().open_connections()
+                    );
+                    continue;
+                }
+                (Poll::Pending, Poll::Pending) => return Poll::Pending,
+                (Poll::Ready(None), Poll::Pending) => {
+                    if *self.as_mut().open_connections() > 0 {
+                        trace!(
+                            "Listener closed; {} open connections.",
+                            self.as_mut().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 +1,630 @@
+// 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, util::deadline_compat, util::AsDuration, util::Compact, ClientMessage,
+    ClientMessageKind, PollIo, Request, Response, ServerError, Transport,
+};
+use fnv::FnvHashMap;
+use futures::{
+    channel::mpsc,
+    future::{abortable, AbortHandle},
+    prelude::*,
+    ready,
+    stream::Fuse,
+    task::{Context, 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::Context, Req) -> Fut + Send + 'static + Clone,
+    Fut: Future<Output = io::Result<Resp>> + Send + 'static,
+{
+    type Output = ();
+
+    fn poll(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<()> {
+        while let Some(channel) = ready!(self.as_mut().incoming().poll_next(cx)) {
+            match channel {
+                Ok(channel) => {
+                    let peer = channel.client_addr;
+                    if let Err(e) =
+                        crate::spawn(channel.respond_with(self.as_mut().request_handler().clone()))
+                    {
+                        warn!("[{}] Failed to spawn connection handler: {:?}", peer, e);
+                    }
+                }
+                Err(e) => {
+                    warn!("Incoming connection error: {}", e);
+                }
+            }
+        }
+        info!("Server shutting down.");
+        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::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(mut self: Pin<&mut Self>, response: Response<Resp>) -> io::Result<()> {
+        self.as_mut().transport().start_send(response)
+    }
+
+    pub(crate) fn poll_ready(
+        mut self: Pin<&mut Self>,
+        cx: &mut Context<'_>,
+    ) -> Poll<io::Result<()>> {
+        self.as_mut().transport().poll_ready(cx)
+    }
+
+    pub(crate) fn poll_flush(
+        mut self: Pin<&mut Self>,
+        cx: &mut Context<'_>,
+    ) -> Poll<io::Result<()>> {
+        self.as_mut().transport().poll_flush(cx)
+    }
+
+    pub(crate) fn poll_next(
+        mut self: Pin<&mut Self>,
+        cx: &mut Context<'_>,
+    ) -> PollIo<ClientMessage<Req>> {
+        self.as_mut().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::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::Context, Response<Resp>)>>,
+    /// Handed out to request handlers to fan in responses.
+    responses_tx: mpsc::Sender<(context::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::Context, Response<Resp>)>>);
+    unsafe_pinned!(responses_tx: mpsc::Sender<(context::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::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(
+        mut self: Pin<&mut Self>,
+        cx: &mut Context<'_>,
+    ) -> Poll<io::Result<()>> {
+        if self.in_flight_requests.len()
+            >= self.channel.config.max_in_flight_requests_per_connection
+        {
+            let peer = self.as_mut().channel().client_addr;
+
+            while let Poll::Pending = self.as_mut().channel().poll_ready(cx)? {
+                info!(
+                    "[{}] In-flight requests at max ({}), and transport is not ready.",
+                    peer,
+                    self.as_mut().in_flight_requests().len(),
+                );
+                try_ready!(self.as_mut().channel().poll_flush(cx));
+            }
+        }
+        Poll::Ready(Ok(()))
+    }
+
+    fn pump_read(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> PollIo<()> {
+        ready!(self.as_mut().poll_ready_if_throttling(cx)?);
+
+        Poll::Ready(match ready!(self.as_mut().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(
+        mut self: Pin<&mut Self>,
+        cx: &mut Context<'_>,
+        read_half_closed: bool,
+    ) -> PollIo<()> {
+        match self.as_mut().poll_next_response(cx)? {
+            Poll::Ready(Some((_, response))) => {
+                self.as_mut().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.as_mut().channel().poll_flush(cx)?);
+                Poll::Ready(None)
+            }
+            Poll::Pending => {
+                // No more requests to process, so flush any requests buffered in the transport.
+                ready!(self.as_mut().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.as_mut().in_flight_requests().is_empty() {
+                    Poll::Ready(None)
+                } else {
+                    Poll::Pending
+                }
+            }
+        }
+    }
+
+    fn poll_next_response(
+        mut self: Pin<&mut Self>,
+        cx: &mut Context<'_>,
+    ) -> PollIo<(context::Context, Response<Resp>)> {
+        // Ensure there's room to write a response.
+        while let Poll::Pending = self.as_mut().channel().poll_ready(cx)? {
+            ready!(self.as_mut().channel().poll_flush(cx)?);
+        }
+
+        let peer = self.as_mut().channel().client_addr;
+
+        match ready!(self.as_mut().pending_responses().poll_next(cx)) {
+            Some((ctx, response)) => {
+                if self
+                    .as_mut()
+                    .in_flight_requests()
+                    .remove(&response.request_id)
+                    .is_some()
+                {
+                    self.as_mut().in_flight_requests().compact(0.1);
+                }
+                trace!(
+                    "[{}/{}] Staging response. In-flight requests = {}.",
+                    ctx.trace_id(),
+                    peer,
+                    self.as_mut().in_flight_requests().len(),
+                );
+                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(
+        mut self: Pin<&mut Self>,
+        trace_context: trace::Context,
+        request: Request<Req>,
+    ) -> io::Result<()> {
+        let request_id = request.id;
+        let peer = self.as_mut().channel().client_addr;
+        let ctx = context::Context {
+            deadline: request.deadline,
+            trace_context,
+        };
+        let request = request.message;
+
+        if self.as_mut().in_flight_requests().len()
+            >= self
+                .as_mut()
+                .channel()
+                .config
+                .max_in_flight_requests_per_connection
+        {
+            debug!(
+                "[{}/{}] Client has reached in-flight request limit ({}/{}).",
+                ctx.trace_id(),
+                peer,
+                self.as_mut().in_flight_requests().len(),
+                self.as_mut()
+                    .channel()
+                    .config
+                    .max_in_flight_requests_per_connection
+            );
+
+            self.as_mut().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.as_mut().responses_tx().clone();
+
+        let trace_id = *ctx.trace_id();
+        let response = self.as_mut().f().clone()(ctx, 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.as_mut()
+            .in_flight_requests()
+            .insert(request_id, abort_handle);
+        Ok(())
+    }
+
+    fn cancel_request(mut self: 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.as_mut().in_flight_requests().remove(&request_id) {
+            self.as_mut().in_flight_requests().compact(0.1);
+
+            cancel_handle.abort();
+            let remaining = self.as_mut().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::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: &mut Context<'_>) -> Poll<io::Result<()>> {
+        trace!("[{}] ClientHandler::poll", self.channel.client_addr);
+        loop {
+            let read = self.as_mut().pump_read(cx)?;
+            match (
+                read,
+                self.as_mut().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 +1,161 @@
+// 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::{PollIo, Transport};
+use futures::{channel::mpsc, task::Context, 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(self: Pin<&mut Self>, cx: &mut Context<'_>) -> PollIo<Item> {
+        self.rx().poll_next(cx).map(|option| option.map(Ok))
+    }
+}
+
+impl<Item, SinkItem> Sink<SinkItem> for UnboundedChannel<Item, SinkItem> {
+    type SinkError = io::Error;
+
+    fn poll_ready(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<io::Result<()>> {
+        self.tx()
+            .poll_ready(cx)
+            .map_err(|_| io::Error::from(io::ErrorKind::NotConnected))
+    }
+
+    fn start_send(self: Pin<&mut Self>, item: SinkItem) -> io::Result<()> {
+        self.tx()
+            .start_send(item)
+            .map_err(|_| io::Error::from(io::ErrorKind::NotConnected))
+    }
+
+    fn poll_flush(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<(), Self::SinkError>> {
+        self.tx()
+            .poll_flush(cx)
+            .map_err(|_| io::Error::from(io::ErrorKind::NotConnected))
+    }
+
+    fn poll_close(self: Pin<&mut Self>, cx: &mut Context<'_>) -> 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 SinkItem = SinkItem;
+    type Item = Item;
+
+    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::Executor01CompatExt;
+    use futures::{prelude::*, stream};
+    use log::trace;
+    use std::io;
+
+    #[test]
+    fn integration() {
+        let _ = env_logger::try_init();
+        crate::init(tokio::executor::DefaultExecutor::current().compat());
+
+        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(future::join(
+            server,
+            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 +1,123 @@
+// 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,
+    marker::PhantomData,
+    net::SocketAddr,
+    pin::Pin,
+    task::{Context, 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<<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, SinkItem, Item>(
+    inner: S,
+    peer_addr: SocketAddr,
+    local_addr: SocketAddr,
+) -> impl Transport<Item = Item, SinkItem = SinkItem>
+where
+    S: Stream<Item = io::Result<Item>>,
+    S: Sink<SinkItem, SinkError = io::Error>,
+{
+    TransportShim {
+        inner,
+        peer_addr,
+        local_addr,
+        _marker: PhantomData,
+    }
+}
+
+/// A transport created by adding peers to a Stream + Sink.
+#[derive(Debug)]
+struct TransportShim<S, SinkItem> {
+    peer_addr: SocketAddr,
+    local_addr: SocketAddr,
+    inner: S,
+    _marker: PhantomData<SinkItem>,
+}
+
+impl<S, SinkItem> TransportShim<S, SinkItem> {
+    pin_utils::unsafe_pinned!(inner: S);
+}
+
+impl<S, SinkItem> Stream for TransportShim<S, SinkItem>
+where
+    S: Stream,
+{
+    type Item = S::Item;
+
+    fn poll_next(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<S::Item>> {
+        self.inner().poll_next(cx)
+    }
+}
+
+impl<S, Item> Sink<Item> for TransportShim<S, Item>
+where
+    S: Sink<Item>,
+{
+    type SinkError = S::SinkError;
+
+    fn start_send(self: Pin<&mut Self>, item: Item) -> Result<(), S::SinkError> {
+        self.inner().start_send(item)
+    }
+
+    fn poll_ready(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<(), S::SinkError>> {
+        self.inner().poll_ready(cx)
+    }
+
+    fn poll_flush(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<(), S::SinkError>> {
+        self.inner().poll_flush(cx)
+    }
+
+    fn poll_close(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<(), S::SinkError>> {
+        self.inner().poll_close(cx)
+    }
+}
+
+impl<S, SinkItem, Item> Transport for TransportShim<S, SinkItem>
+where
+    S: Stream + Sink<SinkItem>,
+    Self: Stream<Item = io::Result<Item>>,
+    Self: Sink<SinkItem, SinkError = io::Error>,
+{
+    type Item = Item;
+    type SinkItem = 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::*,
+    prelude::*,
+    ready,
+    task::{Context, 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>, cx: &mut Context<'_>) -> Poll<Self::Output> {
+        // First, try polling the future
+        match self.as_mut().future().try_poll(cx) {
+            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(cx);
+
+        // 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 +1,96 @@
+// 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`.
+#[allow(clippy::trivially_copy_pass_by_ref)] // Exact fn signature required by serde derive
+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,
+    })
+}

tarpc/Cargo.toml

@@ -1,21 +1,38 @@
 [package]
 name = "tarpc"
-version = "0.4.0"
+version = "0.16.0"
 authors = ["Adam Wright <adam.austin.wright@gmail.com>", "Tim Kuehn <timothy.j.kuehn@gmail.com>"]
+edition = "2018"
 license = "MIT"
-documentation = "https://google.github.io/tarpc"
+documentation = "https://docs.rs/tarpc"
 homepage = "https://github.com/google/tarpc"
 repository = "https://github.com/google/tarpc"
-keywords = ["rpc", "protocol", "remote", "procedure", "serialize"]
+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]
-bincode = "^0.5"
-log = "^0.3"
-scoped-pool = "^0.1"
-serde = "^0.7"
+futures-preview = { version = "0.3.0-alpha.14", features = ["compat"] }
+log = "0.4"
+serde = { optional = true, version = "1.0" }
+rpc = { package = "tarpc-lib", path = "../rpc", version = "0.4" }
+tarpc-plugins = { path = "../plugins", version = "0.5.0" }
 
 [dev-dependencies]
-lazy_static = "^0.1"
-env_logger = "^0.3"
+bincode = "1"
+bytes = { version = "0.4", features = ["serde"] }
+humantime = "1.0"
+bincode-transport = { package = "tarpc-bincode-transport", version = "0.5", path = "../bincode-transport" }
+env_logger = "0.6"
+libtest = "0.0.1"
+tokio = "0.1"
+tokio-executor = "0.1"
+tokio-tcp = "0.1"
+pin-utils = "0.1.0-alpha.4"

tarpc/README.md

@@ -0,0 +1 @@
+../README.md

tarpc/clippy.toml

@@ -0,0 +1 @@
+doc-valid-idents = ["gRPC"]

tarpc/examples/pubsub.rs

@@ -0,0 +1,184 @@
+// 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,
+    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 +1,93 @@
+// 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,
+    arbitrary_self_types,
+    await_macro,
+    async_await,
+    proc_macro_hygiene
+)]
+
+use futures::{
+    compat::Executor01CompatExt,
+    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(tokio::executor::DefaultExecutor::current().compat());
+
+    tokio::run(
+        run()
+            .map_err(|e| eprintln!("Oh no: {}", e))
+            .boxed()
+            .compat(),
+    );
+}

tarpc/examples/server_calling_server.rs

@@ -0,0 +1,107 @@
+// 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,
+    futures_api,
+    await_macro,
+    async_await,
+    proc_macro_hygiene
+)]
+
+use crate::{add::Service as AddService, double::Service as DoubleService};
+use futures::{
+    compat::Executor01CompatExt,
+    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(tokio::executor::DefaultExecutor::current().compat());
+    tokio::run(run().map_err(|e| panic!(e)).boxed().compat());
+}

tarpc/examples/service_registry.rs

@@ -0,0 +1,414 @@
+#![feature(
+    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::{Context, 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>, cx: &mut Context<'_>) -> Poll<Output> {
+            unsafe {
+                match Pin::get_unchecked_mut(self) {
+                    Either::Left(car) => Pin::new_unchecked(car).poll(cx),
+                    Either::Right(cdr) => Pin::new_unchecked(cdr).poll(cx),
+                }
+            }
+        }
+    }
+
+    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::{
+    compat::Executor01CompatExt,
+    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(tokio::executor::DefaultExecutor::current().compat());
+    tokio::run(run().boxed().map_err(|e| panic!(e)).boxed().compat());
+}

tarpc/rustfmt.toml

@@ -1,2 +1 @@
-ideal_width = 100
-reorder_imports = true
+edition = "2018"

tarpc/src/lib.rs

@@ -1,63 +1,26 @@
-// Copyright 2016 Google Inc. All Rights Reserved.
+// Copyright 2018 Google LLC
 //
-// 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 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.
 
-//! An RPC library for Rust.
-//!
-//! Example usage:
-//!
-//! ```
-//! #[macro_use] extern crate tarpc;
-//! mod my_server {
-//!     service! {
-//!         rpc hello(name: String) -> String;
-//!         rpc add(x: i32, y: i32) -> i32;
-//!     }
-//! }
-//!
-//! use self::my_server::*;
-//! use std::time::Duration;
-//!
-//! struct Server;
-//! impl my_server::Service for Server {
-//!     fn hello(&self, s: String) -> String {
-//!         format!("Hello, {}!", s)
-//!     }
-//!     fn add(&self, x: i32, y: i32) -> i32 {
-//!         x + y
-//!     }
-//! }
-//!
-//! fn main() {
-//!     let addr = "127.0.0.1:9000";
-//!     let shutdown = Server.spawn(addr).unwrap();
-//!     let client = Client::new(addr).unwrap();
-//!     assert_eq!(3, client.add(1, 2).unwrap());
-//!     assert_eq!("Hello, Mom!".to_string(),
-//!                client.hello("Mom".to_string()).unwrap());
-//!     drop(client);
-//!     shutdown.shutdown();
-//! }
-//! ```
+#![doc(include = "../README.md")]
+#![deny(missing_docs, missing_debug_implementations)]
+#![feature(async_await, external_doc)]
+#![cfg_attr(
+    test,
+    feature(futures_api, await_macro, proc_macro_hygiene, arbitrary_self_types)
+)]
 
-#![deny(missing_docs)]
-
-extern crate serde;
-extern crate bincode;
-#[macro_use]
-extern crate log;
-extern crate scoped_pool;
-
-macro_rules! pos {
-    () => (concat!(file!(), ":", line!()))
-}
-
-/// Provides the tarpc client and server, which implements the tarpc protocol.
-/// The protocol is defined by the implementation.
-pub mod protocol;
+#[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.
-pub mod macros;
-
-pub use protocol::{Config, Error, Result, ServeHandle};
+#[macro_use]
+mod macros;

tarpc/src/macros.rs

@@ -1,213 +1,28 @@
-// Copyright 2016 Google Inc. All Rights Reserved.
+// Copyright 2018 Google LLC
 //
-// 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 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.
 
-/// Serde re-exports required by macros. Not for general use.
-pub mod serde {
-    pub use serde::{Deserialize, Deserializer, Serialize, Serializer};
-    /// Deserialization re-exports required by macros. Not for general use.
-    pub mod de {
-        pub use serde::de::{EnumVisitor, Error, VariantVisitor, Visitor};
+#[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
     }
 }
 
-// Required because if-let can't be used with irrefutable patterns, so it needs
-// to be special cased.
+#[cfg(not(feature = "serde"))]
 #[doc(hidden)]
 #[macro_export]
-macro_rules! client_methods {
-    (
-        { $(#[$attr:meta])* }
-        $fn_name:ident( ($($arg:ident,)*) : ($($in_:ty,)*) ) -> $out:ty
-    ) => (
-        #[allow(unused)]
+macro_rules! add_serde_if_enabled {
+    ($(#[$attr:meta])* -- $i:item) => {
         $(#[$attr])*
-        pub fn $fn_name(&self, $($arg: $in_),*) -> $crate::Result<$out> {
-            let reply = try!((self.0).rpc(__Request::$fn_name(($($arg,)*))));
-            let __Reply::$fn_name(reply) = reply;
-            ::std::result::Result::Ok(reply)
-        }
-    );
-    ($(
-            { $(#[$attr:meta])* }
-            $fn_name:ident( ($( $arg:ident,)*) : ($($in_:ty, )*) ) -> $out:ty
-    )*) => ( $(
-        #[allow(unused)]
-        $(#[$attr])*
-        pub fn $fn_name(&self, $($arg: $in_),*) -> $crate::Result<$out> {
-            let reply = try!((self.0).rpc(__Request::$fn_name(($($arg,)*))));
-            if let __Reply::$fn_name(reply) = reply {
-                ::std::result::Result::Ok(reply)
-            } else {
-                panic!("Incorrect reply variant returned from rpc; expected `{}`, \
-                       but got {:?}",
-                       stringify!($fn_name),
-                       reply);
-            }
-        }
-    )*);
-}
-
-// Required because if-let can't be used with irrefutable patterns, so it needs
-// to be special cased.
-#[doc(hidden)]
-#[macro_export]
-macro_rules! async_client_methods {
-    (
-        { $(#[$attr:meta])* }
-        $fn_name:ident( ($( $arg:ident, )*) : ($( $in_:ty, )*) ) -> $out:ty
-    ) => (
-        #[allow(unused)]
-        $(#[$attr])*
-        pub fn $fn_name(&self, $($arg: $in_),*) -> Future<$out> {
-            fn mapper(reply: __Reply) -> $out {
-                let __Reply::$fn_name(reply) = reply;
-                reply
-            }
-            let reply = (self.0).rpc_async(__Request::$fn_name(($($arg,)*)));
-            Future {
-                future: reply,
-                mapper: mapper,
-            }
-        }
-    );
-    ($(
-            { $(#[$attr:meta])* }
-            $fn_name:ident( ($( $arg:ident, )*) : ($( $in_:ty, )*) ) -> $out:ty
-    )*) => ( $(
-        #[allow(unused)]
-        $(#[$attr])*
-        pub fn $fn_name(&self, $($arg: $in_),*) -> Future<$out> {
-            fn mapper(reply: __Reply) -> $out {
-                if let __Reply::$fn_name(reply) = reply {
-                    reply
-                } else {
-                    panic!("Incorrect reply variant returned from rpc; expected `{}`, but got \
-                           {:?}",
-                           stringify!($fn_name),
-                           reply);
-                }
-            }
-            let reply = (self.0).rpc_async(__Request::$fn_name(($($arg,)*)));
-            Future {
-                future: reply,
-                mapper: mapper,
-            }
-        }
-    )*);
-}
-
-#[doc(hidden)]
-#[macro_export]
-macro_rules! impl_serialize {
-    ($impler:ident, $(@($name:ident $n:expr))* -- #($_n:expr) ) => (
-        impl $crate::macros::serde::Serialize for $impler {
-            #[inline]
-            fn serialize<S>(&self, serializer: &mut S) -> ::std::result::Result<(), S::Error>
-                where S: $crate::macros::serde::Serializer
-            {
-                match *self {
-                    $(
-                        $impler::$name(ref field) =>
-                            $crate::macros::serde::Serializer::serialize_newtype_variant(
-                                serializer,
-                                stringify!($impler),
-                                $n,
-                                stringify!($name),
-                                field,
-                            )
-                    ),*
-                }
-            }
-        }
-    );
-    // All args are wrapped in a tuple so we can use the newtype variant for each one.
-    ($impler:ident, $(@$finished:tt)* -- #($n:expr) $name:ident($field:ty) $($req:tt)*) => (
-        impl_serialize!($impler, $(@$finished)* @($name $n) -- #($n + 1) $($req)*);
-    );
-    // Entry
-    ($impler:ident, $($started:tt)*) => (impl_serialize!($impler, -- #(0) $($started)*););
-}
-
-#[doc(hidden)]
-#[macro_export]
-macro_rules! impl_deserialize {
-    ($impler:ident, $(@($name:ident $n:expr))* -- #($_n:expr) ) => (
-        impl $crate::macros::serde::Deserialize for $impler {
-            #[inline]
-            fn deserialize<D>(deserializer: &mut D)
-                -> ::std::result::Result<$impler, D::Error>
-                where D: $crate::macros::serde::Deserializer
-            {
-                #[allow(non_camel_case_types, unused)]
-                enum __Field {
-                    $($name),*
-                }
-                impl $crate::macros::serde::Deserialize for __Field {
-                    #[inline]
-                    fn deserialize<D>(deserializer: &mut D)
-                        -> ::std::result::Result<__Field, D::Error>
-                        where D: $crate::macros::serde::Deserializer
-                    {
-                        struct __FieldVisitor;
-                        impl $crate::macros::serde::de::Visitor for __FieldVisitor {
-                            type Value = __Field;
-
-                            #[inline]
-                            fn visit_usize<E>(&mut self, value: usize)
-                                -> ::std::result::Result<__Field, E>
-                                where E: $crate::macros::serde::de::Error,
-                            {
-                                $(
-                                    if value == $n {
-                                        return ::std::result::Result::Ok(__Field::$name);
-                                    }
-                                )*
-                                return ::std::result::Result::Err(
-                                    $crate::macros::serde::de::Error::custom(
-                                        format!("No variants have a value of {}!", value))
-                                );
-                            }
-                        }
-                        deserializer.deserialize_struct_field(__FieldVisitor)
-                    }
-                }
-
-                struct __Visitor;
-                impl $crate::macros::serde::de::EnumVisitor for __Visitor {
-                    type Value = $impler;
-
-                    #[inline]
-                    fn visit<__V>(&mut self, mut visitor: __V)
-                        -> ::std::result::Result<$impler, __V::Error>
-                        where __V: $crate::macros::serde::de::VariantVisitor
-                    {
-                        match try!(visitor.visit_variant()) {
-                            $(
-                                __Field::$name => {
-                                    let val = try!(visitor.visit_newtype());
-                                    Ok($impler::$name(val))
-                                }
-                            ),*
-                        }
-                    }
-                }
-                const VARIANTS: &'static [&'static str] = &[
-                    $(
-                        stringify!($name)
-                    ),*
-                ];
-                deserializer.deserialize_enum(stringify!($impler), VARIANTS, __Visitor)
-            }
-        }
-    );
-    // All args are wrapped in a tuple so we can use the newtype variant for each one.
-    ($impler:ident, $(@$finished:tt)* -- #($n:expr) $name:ident($field:ty) $($req:tt)*) => (
-        impl_deserialize!($impler, $(@$finished)* @($name $n) -- #($n + 1) $($req)*);
-    );
-    // Entry
-    ($impler:ident, $($started:tt)*) => (impl_deserialize!($impler, -- #(0) $($started)*););
+        $i
+    }
 }
 
 /// The main macro that creates RPC services.
@@ -215,54 +30,45 @@ macro_rules! impl_deserialize {
 /// Rpc methods are specified, mirroring trait syntax:
 ///
 /// ```
-/// # #[macro_use] extern crate tarpc;
+/// # #![feature(await_macro, pin, arbitrary_self_types, async_await, futures_api, proc_macro_hygiene)]
 /// # fn main() {}
-/// # service! {
-/// #[doc="Say hello"]
+/// # tarpc::service! {
+/// /// Say hello
 /// rpc hello(name: String) -> String;
 /// # }
 /// ```
 ///
-/// There are two rpc names reserved for the default fns `spawn` and `spawn_with_config`.
-///
 /// Attributes can be attached to each rpc. These attributes
-/// will then be attached to the generated `Service` trait's
-/// corresponding method, as well as to the `Client` stub's rpcs methods.
+/// 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:
 ///
-/// * `Service` -- the trait defining the RPC service. It comes with two default methods for
-///                starting the server:
-///                1. `spawn` starts the service in another thread using default configuration.
-///                2. `spawn_with_config` starts the service in another thread using the specified
-///                   `Config`.
-/// * `Client` -- a client that makes synchronous requests to the RPC server
-/// * `AsyncClient` -- a client that makes asynchronous requests to the RPC server
-/// * `Future` -- a handle for asynchronously retrieving the result of an RPC
+/// * `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.
 ///
-/// **Warning**: In addition to the above items, there are a few expanded items that
-/// are considered implementation details. As with the above items, shadowing
-/// these item names in the enclosing module is likely to break things in confusing
-/// ways:
-///
-/// * `__Server` -- an implementation detail
-/// * `__Request` -- an implementation detail
-/// * `__Reply` -- an implementation detail
 #[macro_export]
 macro_rules! service {
+    () => {
+        compile_error!("Must define at least one RPC method.");
+    };
+// Entry point
     (
-        $( $tokens:tt )*
+        $(
+            $(#[$attr:meta])*
+            rpc $fn_name:ident( $( $arg:ident : $in_:ty ),* ) $(-> $out:ty)*;
+        )*
     ) => {
-        service_inner! {{
-            $( $tokens )*
+        $crate::service! {{
+            $(
+                $(#[$attr])*
+                rpc $fn_name( $( $arg : $in_ ),* ) $(-> $out)*;
+            )*
         }}
-    }
-}
-
-#[doc(hidden)]
-#[macro_export]
-macro_rules! service_inner {
-    // Pattern for when the next rpc has an implicit unit return type
+    };
+// Pattern for when the next rpc has an implicit unit return type.
     (
         {
             $(#[$attr:meta])*
@@ -272,7 +78,7 @@ macro_rules! service_inner {
         }
         $( $expanded:tt )*
     ) => {
-        service_inner! {
+        $crate::service! {
             { $( $unexpanded )* }
 
             $( $expanded )*
@@ -281,7 +87,7 @@ macro_rules! service_inner {
             rpc $fn_name( $( $arg : $in_ ),* ) -> ();
         }
     };
-    // Pattern for when the next rpc has an explicit return type
+// Pattern for when the next rpc has an explicit return type.
     (
         {
             $(#[$attr:meta])*
@@ -291,7 +97,7 @@ macro_rules! service_inner {
         }
         $( $expanded:tt )*
     ) => {
-        service_inner! {
+        $crate::service! {
             { $( $unexpanded )* }
 
             $( $expanded )*
@@ -300,7 +106,7 @@ macro_rules! service_inner {
             rpc $fn_name( $( $arg : $in_ ),* ) -> $out;
         }
     };
-    // Pattern when all return types have been expanded
+// Pattern for when all return types have been expanded
     (
         { } // none left to expand
         $(
@@ -308,286 +114,264 @@ macro_rules! service_inner {
             rpc $fn_name:ident ( $( $arg:ident : $in_:ty ),* ) -> $out:ty;
         )*
     ) => {
-        #[doc="Defines the RPC service"]
-        pub trait Service: Send + Sync + Sized {
+        $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 $fn_name(&self, $($arg:$in_),*) -> $out;
+                $fn_name($crate::ty_snake_to_camel!(<S as Service>::$fn_name)),
             )*
+        }
 
-            #[doc="Spawn a running service."]
-            fn spawn<A>(self, addr: A) -> $crate::Result<$crate::protocol::ServeHandle>
-                where A: ::std::net::ToSocketAddrs,
-                      Self: 'static,
-            {
-                self.spawn_with_config(addr, $crate::Config::default())
-            }
-
-            #[doc="Spawn a running service."]
-            fn spawn_with_config<A>(self, addr: A, config: $crate::Config)
-                -> $crate::Result<$crate::protocol::ServeHandle>
-                where A: ::std::net::ToSocketAddrs,
-                      Self: 'static,
-            {
-                let server = ::std::sync::Arc::new(__Server(self));
-                let handle = try!($crate::protocol::Serve::spawn_with_config(server, addr, config));
-                ::std::result::Result::Ok(handle)
+        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<P, S> Service for P
-            where P: Send + Sync + Sized + 'static + ::std::ops::Deref<Target=S>,
-                  S: Service
+        impl<S: Service> ::std::future::Future for ResponseFut<S> {
+            type Output = ::std::io::Result<Response>;
+
+            fn poll(self: ::std::pin::Pin<&mut Self>, cx: &mut ::std::task::Context<'_>)
+                -> ::std::task::Poll<::std::io::Result<Response>>
+            {
+                unsafe {
+                    match ::std::pin::Pin::get_unchecked_mut(self) {
+                        $(
+                            ResponseFut::$fn_name(resp) =>
+                                ::std::pin::Pin::new_unchecked(resp)
+                                    .poll(cx)
+                                    .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])*
-                fn $fn_name(&self, $($arg:$in_),*) -> $out {
-                    Service::$fn_name(&**self, $($arg),*)
+                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(non_camel_case_types, unused)]
-        #[derive(Debug)]
-        enum __Request {
-            $(
-                $fn_name(( $($in_,)* ))
-            ),*
-        }
-
-        impl_serialize!(__Request, $($fn_name(($($in_),*)))*);
-        impl_deserialize!(__Request, $($fn_name(($($in_),*)))*);
-
-        #[allow(non_camel_case_types, unused)]
-        #[derive(Debug)]
-        enum __Reply {
-            $(
-                $fn_name($out),
-            )*
-        }
-
-        impl_serialize!(__Reply, $($fn_name($out))*);
-        impl_deserialize!(__Reply, $($fn_name($out))*);
-
-        #[allow(unused)]
-        #[doc="An asynchronous RPC call"]
-        pub struct Future<T> {
-            future: $crate::protocol::Future<__Reply>,
-            mapper: fn(__Reply) -> T,
-        }
-
-        impl<T> Future<T> {
-            #[allow(unused)]
-            #[doc="Block until the result of the RPC call is available"]
-            pub fn get(self) -> $crate::Result<T> {
-                self.future.get().map(self.mapper)
-            }
-        }
-
-        #[allow(unused)]
-        #[doc="The client stub that makes RPC calls to the server."]
-        pub struct Client($crate::protocol::Client<__Request, __Reply>);
-
-        impl Client {
-            #[allow(unused)]
-            #[doc="Create a new client with default configuration that connects to the given \
-                   address."]
-            pub fn new<A>(addr: A) -> $crate::Result<Self>
-                where A: ::std::net::ToSocketAddrs,
-            {
-                Self::with_config(addr, $crate::Config::default())
-            }
-
-            #[allow(unused)]
-            #[doc="Create a new client with the specified configuration that connects to the \
-                   given address."]
-            pub fn with_config<A>(addr: A, config: $crate::Config) -> $crate::Result<Self>
-                where A: ::std::net::ToSocketAddrs,
-            {
-                let inner = try!($crate::protocol::Client::with_config(addr, config));
-                ::std::result::Result::Ok(Client(inner))
-            }
-
-            client_methods!(
-                $(
-                    { $(#[$attr])* }
-                    $fn_name(($($arg,)*) : ($($in_,)*)) -> $out
-                )*
-            );
-
-            #[allow(unused)]
-            #[doc="Attempt to clone the client object. This might fail if the underlying TcpStream \
-                   clone fails."]
-            pub fn try_clone(&self) -> ::std::io::Result<Self> {
-                ::std::result::Result::Ok(Client(try!(self.0.try_clone())))
-            }
-        }
-
-        #[allow(unused)]
-        #[doc="The client stub that makes asynchronous RPC calls to the server."]
-        pub struct AsyncClient($crate::protocol::Client<__Request, __Reply>);
-
-        impl AsyncClient {
-            #[allow(unused)]
-            #[doc="Create a new asynchronous client with default configuration that connects to \
-                   the given address."]
-            pub fn new<A>(addr: A) -> $crate::Result<Self>
-                where A: ::std::net::ToSocketAddrs,
-            {
-                Self::with_config(addr, $crate::Config::default())
-            }
-
-            #[allow(unused)]
-            #[doc="Create a new asynchronous client that connects to the given address."]
-            pub fn with_config<A>(addr: A, config: $crate::Config)
-                -> $crate::Result<Self>
-                where A: ::std::net::ToSocketAddrs,
-            {
-                let inner = try!($crate::protocol::Client::with_config(addr, config));
-                ::std::result::Result::Ok(AsyncClient(inner))
-            }
-
-            async_client_methods!(
-                $(
-                    { $(#[$attr])* }
-                    $fn_name(($($arg,)*): ($($in_,)*)) -> $out
-                )*
-            );
-
-            #[allow(unused)]
-            #[doc="Attempt to clone the client object. This might fail if the underlying TcpStream \
-                   clone fails."]
-            pub fn try_clone(&self) -> ::std::io::Result<Self> {
-                ::std::result::Result::Ok(AsyncClient(try!(self.0.try_clone())))
-            }
-        }
-
-        #[allow(unused)]
-        struct __Server<S: 'static + Service>(S);
-
-        impl<S> $crate::protocol::Serve for __Server<S>
-            where S: 'static + Service
-        {
-            type Request = __Request;
-            type Reply = __Reply;
-            fn serve(&self, request: __Request) -> __Reply {
-                match request {
-                    $(
-                        __Request::$fn_name(( $($arg,)* )) =>
-                            __Reply::$fn_name((self.0).$fn_name($($arg),*)),
-                    )*
-                }
-            }
-        }
     }
 }
 
-#[allow(dead_code)] // because we're just testing that the macro expansion compiles
+// allow dead code; we're just testing that the macro expansion compiles
+#[allow(dead_code)]
 #[cfg(test)]
 mod syntax_test {
-    // Tests a service definition with a fn that takes no args
-    mod qux {
-        service! {
-            rpc hello() -> String;
-        }
-    }
-    // Tests a service definition with an attribute.
-    mod bar {
-        service! {
-            #[doc="Hello bob"]
-            rpc baz(s: String) -> String;
-        }
-    }
-
-    // Tests a service with implicit return types.
-    mod no_return {
-        service! {
-            rpc ack();
-            rpc apply(foo: String) -> i32;
-            rpc bi_consume(bar: String, baz: u64);
-            rpc bi_fn(bar: String, baz: u64) -> String;
-        }
+    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 {
-    extern crate env_logger;
+    use futures::{
+        compat::Executor01CompatExt,
+        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 {
-        fn add(&self, x: i32, y: i32) -> i32 {
-            x + y
+        type AddFut = Ready<i32>;
+
+        fn add(self, _: context::Context, x: i32, y: i32) -> Self::AddFut {
+            ready(x + y)
         }
-        fn hey(&self, name: String) -> String {
-            format!("Hey, {}.", name)
+
+        type HeyFut = Ready<String>;
+
+        fn hey(self, _: context::Context, name: String) -> Self::HeyFut {
+            ready(format!("Hey, {}.", name))
         }
     }
 
     #[test]
-    fn simple() {
-        let _ = env_logger::init();
-        let handle = Server.spawn("localhost:0").unwrap();
-        let client = Client::new(handle.local_addr()).unwrap();
-        assert_eq!(3, client.add(1, 2).unwrap());
-        assert_eq!("Hey, Tim.", client.hey("Tim".into()).unwrap());
-        drop(client);
-        handle.shutdown();
-    }
+    fn sequential() {
+        let _ = env_logger::try_init();
+        rpc::init(tokio::executor::DefaultExecutor::current().compat());
 
-    #[test]
-    fn simple_async() {
-        let _ = env_logger::init();
-        let handle = Server.spawn("localhost:0").unwrap();
-        let client = AsyncClient::new(handle.local_addr()).unwrap();
-        assert_eq!(3, client.add(1, 2).get().unwrap());
-        assert_eq!("Hey, Adam.", client.hey("Adam".into()).get().unwrap());
-        drop(client);
-        handle.shutdown();
-    }
+        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(),
+            );
 
-    #[test]
-    fn try_clone() {
-        let handle = Server.spawn("localhost:0").unwrap();
-        let client1 = Client::new(handle.local_addr()).unwrap();
-        let client2 = client1.try_clone().unwrap();
-        assert_eq!(3, client1.add(1, 2).unwrap());
-        assert_eq!(3, client2.add(1, 2).unwrap());
-    }
-
-    #[test]
-    fn async_try_clone() {
-        let handle = Server.spawn("localhost:0").unwrap();
-        let client1 = AsyncClient::new(handle.local_addr()).unwrap();
-        let client2 = client1.try_clone().unwrap();
-        assert_eq!(3, client1.add(1, 2).get().unwrap());
-        assert_eq!(3, client2.add(1, 2).get().unwrap());
-    }
-
-    // Tests that a server can be wrapped in an Arc; no need to run, just compile
-    #[allow(dead_code)]
-    fn serve_arc_server() {
-        let _ = ::std::sync::Arc::new(Server).spawn("localhost:0");
-    }
-
-    #[test]
-    fn serde() {
-        use bincode;
-        let _ = env_logger::init();
-
-        let request = __Request::add((1, 2));
-        let ser = bincode::serde::serialize(&request, bincode::SizeLimit::Infinite).unwrap();
-        let de = bincode::serde::deserialize(&ser).unwrap();
-        if let __Request::add((1, 2)) = de {
-            // success
-        } else {
-            panic!("Expected __Request::add, got {:?}", de);
+            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(tokio::executor::DefaultExecutor::current().compat());
+
+        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/src/protocol/client.rs

@@ -1,260 +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;
-use std::fmt;
-use std::io::{self, BufReader, BufWriter, Read};
-use std::collections::HashMap;
-use std::mem;
-use std::net::{TcpStream, ToSocketAddrs};
-use std::sync::{Arc, Mutex};
-use std::sync::mpsc::{Receiver, Sender, channel};
-use std::thread;
-
-use super::{Config, Deserialize, Error, Packet, Result, Serialize};
-
-/// A client stub that connects to a server to run rpcs.
-pub struct Client<Request, Reply>
-    where Request: serde::ser::Serialize
-{
-    // The guard is in an option so it can be joined in the drop fn
-    reader_guard: Arc<Option<thread::JoinHandle<()>>>,
-    outbound: Sender<(Request, Sender<Result<Reply>>)>,
-    requests: Arc<Mutex<RpcFutures<Reply>>>,
-    shutdown: TcpStream,
-}
-
-impl<Request, Reply> Client<Request, Reply>
-    where Request: serde::ser::Serialize + Send + 'static,
-          Reply: serde::de::Deserialize + Send + 'static
-{
-    /// Create a new client that connects to `addr`. The client uses the given timeout
-    /// for both reads and writes.
-    pub fn new<A: ToSocketAddrs>(addr: A) -> io::Result<Self> {
-        Self::with_config(addr, Config::default())
-    }
-
-    /// Create a new client that connects to `addr`. The client uses the given timeout
-    /// for both reads and writes.
-    pub fn with_config<A: ToSocketAddrs>(addr: A, config: Config) -> io::Result<Self> {
-        let stream = try!(TcpStream::connect(addr));
-        try!(stream.set_read_timeout(config.timeout));
-        try!(stream.set_write_timeout(config.timeout));
-        let reader_stream = try!(stream.try_clone());
-        let writer_stream = try!(stream.try_clone());
-        let requests = Arc::new(Mutex::new(RpcFutures::new()));
-        let reader_requests = requests.clone();
-        let writer_requests = requests.clone();
-        let (tx, rx) = channel();
-        let reader_guard = thread::spawn(move || read(reader_requests, reader_stream));
-        thread::spawn(move || write(rx, writer_requests, writer_stream));
-        Ok(Client {
-            reader_guard: Arc::new(Some(reader_guard)),
-            outbound: tx,
-            requests: requests,
-            shutdown: stream,
-        })
-    }
-
-    /// Clones the Client so that it can be shared across threads.
-    pub fn try_clone(&self) -> io::Result<Client<Request, Reply>> {
-        Ok(Client {
-            reader_guard: self.reader_guard.clone(),
-            outbound: self.outbound.clone(),
-            requests: self.requests.clone(),
-            shutdown: try!(self.shutdown.try_clone()),
-        })
-    }
-
-    fn rpc_internal(&self, request: Request) -> Receiver<Result<Reply>>
-        where Request: serde::ser::Serialize + fmt::Debug + Send + 'static
-    {
-        let (tx, rx) = channel();
-        self.outbound.send((request, tx)).expect(pos!());
-        rx
-    }
-
-    /// Run the specified rpc method on the server this client is connected to
-    pub fn rpc(&self, request: Request) -> Result<Reply>
-        where Request: serde::ser::Serialize + fmt::Debug + Send + 'static
-    {
-        self.rpc_internal(request)
-            .recv()
-            .map_err(|_| self.requests.lock().expect(pos!()).get_error())
-            .and_then(|reply| reply)
-    }
-
-    /// Asynchronously run the specified rpc method on the server this client is connected to
-    pub fn rpc_async(&self, request: Request) -> Future<Reply>
-        where Request: serde::ser::Serialize + fmt::Debug + Send + 'static
-    {
-        Future {
-            rx: self.rpc_internal(request),
-            requests: self.requests.clone(),
-        }
-    }
-}
-
-impl<Request, Reply> Drop for Client<Request, Reply>
-    where Request: serde::ser::Serialize
-{
-    fn drop(&mut self) {
-        debug!("Dropping Client.");
-        if let Some(reader_guard) = Arc::get_mut(&mut self.reader_guard) {
-            debug!("Attempting to shut down writer and reader threads.");
-            if let Err(e) = self.shutdown.shutdown(::std::net::Shutdown::Both) {
-                warn!("Client: couldn't shutdown writer and reader threads: {:?}",
-                      e);
-            } else {
-                // We only join if we know the TcpStream was shut down. Otherwise we might never
-                // finish.
-                debug!("Joining writer and reader.");
-                reader_guard.take()
-                            .expect(pos!())
-                            .join()
-                            .expect(pos!());
-                debug!("Successfully joined writer and reader.");
-            }
-        }
-    }
-}
-
-/// An asynchronous RPC call
-pub struct Future<T> {
-    rx: Receiver<Result<T>>,
-    requests: Arc<Mutex<RpcFutures<T>>>,
-}
-
-impl<T> Future<T> {
-    /// Block until the result of the RPC call is available
-    pub fn get(self) -> Result<T> {
-        let requests = self.requests;
-        self.rx
-            .recv()
-            .map_err(|_| requests.lock().expect(pos!()).get_error())
-            .and_then(|reply| reply)
-    }
-}
-
-struct RpcFutures<Reply>(Result<HashMap<u64, Sender<Result<Reply>>>>);
-
-impl<Reply> RpcFutures<Reply> {
-    fn new() -> RpcFutures<Reply> {
-        RpcFutures(Ok(HashMap::new()))
-    }
-
-    fn insert_tx(&mut self, id: u64, tx: Sender<Result<Reply>>) -> Result<()> {
-        match self.0 {
-            Ok(ref mut requests) => {
-                requests.insert(id, tx);
-                Ok(())
-            }
-            Err(ref e) => Err(e.clone()),
-        }
-    }
-
-    fn remove_tx(&mut self, id: u64) -> Result<()> {
-        match self.0 {
-            Ok(ref mut requests) => {
-                requests.remove(&id);
-                Ok(())
-            }
-            Err(ref e) => Err(e.clone()),
-        }
-    }
-
-    fn complete_reply(&mut self, packet: Packet<Reply>) {
-        if let Some(tx) = self.0.as_mut().expect(pos!()).remove(&packet.rpc_id) {
-            if let Err(e) = tx.send(Ok(packet.message)) {
-                info!("Reader: could not complete reply: {:?}", e);
-            }
-        } else {
-            warn!("RpcFutures: expected sender for id {} but got None!",
-                  packet.rpc_id);
-        }
-    }
-
-    fn set_error(&mut self, err: Error) {
-        let _ = mem::replace(&mut self.0, Err(err));
-    }
-
-    fn get_error(&self) -> Error {
-        self.0.as_ref().err().expect(pos!()).clone()
-    }
-}
-
-fn write<Request, Reply>(outbound: Receiver<(Request, Sender<Result<Reply>>)>,
-                         requests: Arc<Mutex<RpcFutures<Reply>>>,
-                         stream: TcpStream)
-    where Request: serde::Serialize,
-          Reply: serde::Deserialize
-{
-    let mut next_id = 0;
-    let mut stream = BufWriter::new(stream);
-    loop {
-        let (request, tx) = match outbound.recv() {
-            Err(e) => {
-                debug!("Writer: all senders have exited ({:?}). Returning.", e);
-                return;
-            }
-            Ok(request) => request,
-        };
-        if let Err(e) = requests.lock().expect(pos!()).insert_tx(next_id, tx.clone()) {
-            report_error(&tx, e);
-            // Once insert_tx returns Err, it will continue to do so. However, continue here so
-            // that any other clients who sent requests will also recv the Err.
-            continue;
-        }
-        let id = next_id;
-        next_id += 1;
-        let packet = Packet {
-            rpc_id: id,
-            message: request,
-        };
-        debug!("Writer: writing rpc, id={:?}", id);
-        if let Err(e) = stream.serialize(&packet) {
-            report_error(&tx, e.into());
-            // Typically we'd want to notify the client of any Err returned by remove_tx, but in
-            // this case the client already hit an Err, and doesn't need to know about this one, as
-            // well.
-            let _ = requests.lock().expect(pos!()).remove_tx(id);
-            continue;
-        }
-    }
-
-    fn report_error<Reply>(tx: &Sender<Result<Reply>>, e: Error)
-        where Reply: serde::Deserialize
-    {
-        // Clone the err so we can log it if sending fails
-        if let Err(e2) = tx.send(Err(e.clone())) {
-            debug!("Error encountered while trying to send an error. Initial error: {:?}; Send \
-                    error: {:?}",
-                   e,
-                   e2);
-        }
-    }
-
-}
-
-fn read<Reply>(requests: Arc<Mutex<RpcFutures<Reply>>>, stream: TcpStream)
-    where Reply: serde::Deserialize
-{
-    let mut stream = BufReader::new(stream);
-    loop {
-        match stream.deserialize::<Packet<Reply>>() {
-            Ok(packet) => {
-                debug!("Client: received message, id={}", packet.rpc_id);
-                requests.lock().expect(pos!()).complete_reply(packet);
-            }
-            Err(err) => {
-                warn!("Client: reader thread encountered an unexpected error while parsing; \
-                       returning now. Error: {:?}",
-                      err);
-                requests.lock().expect(pos!()).set_error(err);
-                break;
-            }
-        }
-    }
-}

tarpc/src/protocol/mod.rs

@@ -1,253 +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::{self, SizeLimit};
-use bincode::serde::{deserialize_from, serialize_into};
-use serde;
-use serde::de::value::Error::EndOfStream;
-use std::io::{self, Read, Write};
-use std::convert;
-use std::sync::Arc;
-use std::time::Duration;
-
-mod client;
-mod server;
-mod packet;
-
-pub use self::packet::Packet;
-pub use self::client::{Client, Future};
-pub use self::server::{Serve, ServeHandle};
-
-/// Client errors that can occur during rpc calls
-#[derive(Debug, Clone)]
-pub enum Error {
-    /// An IO-related error
-    Io(Arc<io::Error>),
-    /// The server hung up.
-    ConnectionBroken,
-}
-
-impl convert::From<bincode::serde::SerializeError> for Error {
-    fn from(err: bincode::serde::SerializeError) -> Error {
-        match err {
-            bincode::serde::SerializeError::IoError(err) => Error::Io(Arc::new(err)),
-            err => panic!("Unexpected error during serialization: {:?}", err),
-        }
-    }
-}
-
-impl convert::From<bincode::serde::DeserializeError> for Error {
-    fn from(err: bincode::serde::DeserializeError) -> Error {
-        match err {
-            bincode::serde::DeserializeError::Serde(EndOfStream) => Error::ConnectionBroken,
-            bincode::serde::DeserializeError::IoError(err) => {
-                match err.kind() {
-                    io::ErrorKind::ConnectionReset |
-                    io::ErrorKind::UnexpectedEof => Error::ConnectionBroken,
-                    _ => Error::Io(Arc::new(err)),
-                }
-            }
-            err => panic!("Unexpected error during deserialization: {:?}", err),
-        }
-    }
-}
-
-impl convert::From<io::Error> for Error {
-    fn from(err: io::Error) -> Error {
-        Error::Io(Arc::new(err))
-    }
-}
-
-/// Configuration for client and server.
-#[derive(Debug, Default)]
-pub struct Config {
-    /// Request/Response timeout between packet delivery.
-    pub timeout: Option<Duration>,
-}
-
-/// Return type of rpc calls: either the successful return value, or a client error.
-pub type Result<T> = ::std::result::Result<T, Error>;
-
-trait Deserialize: Read + Sized {
-    fn deserialize<T: serde::Deserialize>(&mut self) -> Result<T> {
-        deserialize_from(self, SizeLimit::Infinite).map_err(Error::from)
-    }
-}
-
-impl<R: Read> Deserialize for R {}
-
-trait Serialize: Write + Sized {
-    fn serialize<T: serde::Serialize>(&mut self, value: &T) -> Result<()> {
-        try!(serialize_into(self, value, SizeLimit::Infinite));
-        try!(self.flush());
-        Ok(())
-    }
-}
-
-impl<W: Write> Serialize for W {}
-
-#[cfg(test)]
-mod test {
-    extern crate env_logger;
-    use super::{Client, Config, Serve};
-    use scoped_pool::Pool;
-    use std::sync::{Arc, Barrier, Mutex};
-    use std::thread;
-    use std::time::Duration;
-
-    fn test_timeout() -> Option<Duration> {
-        Some(Duration::from_secs(1))
-    }
-
-    struct Server {
-        counter: Mutex<u64>,
-    }
-
-    impl Serve for Server {
-        type Request = ();
-        type Reply = u64;
-
-        fn serve(&self, _: ()) -> u64 {
-            let mut counter = self.counter.lock().unwrap();
-            let reply = *counter;
-            *counter += 1;
-            reply
-        }
-    }
-
-    impl Server {
-        fn new() -> Server {
-            Server { counter: Mutex::new(0) }
-        }
-
-        fn count(&self) -> u64 {
-            *self.counter.lock().unwrap()
-        }
-    }
-
-    #[test]
-    fn handle() {
-        let _ = env_logger::init();
-        let server = Arc::new(Server::new());
-        let serve_handle = server.spawn("localhost:0").unwrap();
-        let client: Client<(), u64> = Client::new(serve_handle.local_addr()).unwrap();
-        drop(client);
-        serve_handle.shutdown();
-    }
-
-    #[test]
-    fn simple() {
-        let _ = env_logger::init();
-        let server = Arc::new(Server::new());
-        let serve_handle = server.clone().spawn("localhost:0").unwrap();
-        let addr = serve_handle.local_addr().clone();
-        // The explicit type is required so that it doesn't deserialize a u32 instead of u64
-        let client: Client<(), u64> = Client::new(addr).unwrap();
-        assert_eq!(0, client.rpc(()).unwrap());
-        assert_eq!(1, server.count());
-        assert_eq!(1, client.rpc(()).unwrap());
-        assert_eq!(2, server.count());
-        drop(client);
-        serve_handle.shutdown();
-    }
-
-    struct BarrierServer {
-        barrier: Barrier,
-        inner: Server,
-    }
-
-    impl Serve for BarrierServer {
-        type Request = ();
-        type Reply = u64;
-        fn serve(&self, request: ()) -> u64 {
-            self.barrier.wait();
-            self.inner.serve(request)
-        }
-    }
-
-    impl BarrierServer {
-        fn new(n: usize) -> BarrierServer {
-            BarrierServer {
-                barrier: Barrier::new(n),
-                inner: Server::new(),
-            }
-        }
-
-        fn count(&self) -> u64 {
-            self.inner.count()
-        }
-    }
-
-    #[test]
-    fn force_shutdown() {
-        let _ = env_logger::init();
-        let server = Arc::new(Server::new());
-        let serve_handle = server.spawn_with_config("localhost:0",
-                                                    Config { timeout: Some(Duration::new(0, 10)) })
-                                 .unwrap();
-        let addr = serve_handle.local_addr().clone();
-        let client: Client<(), u64> = Client::new(addr).unwrap();
-        let thread = thread::spawn(move || serve_handle.shutdown());
-        info!("force_shutdown:: rpc1: {:?}", client.rpc(()));
-        thread.join().unwrap();
-    }
-
-    #[test]
-    fn client_failed_rpc() {
-        let _ = env_logger::init();
-        let server = Arc::new(Server::new());
-        let serve_handle = server.spawn_with_config("localhost:0",
-                                                    Config { timeout: test_timeout() })
-                                 .unwrap();
-        let addr = serve_handle.local_addr().clone();
-        let client: Arc<Client<(), u64>> = Arc::new(Client::new(addr).unwrap());
-        client.rpc(()).unwrap();
-        serve_handle.shutdown();
-        match client.rpc(()) {
-            Err(super::Error::ConnectionBroken) => {} // success
-            otherwise => panic!("Expected Err(ConnectionBroken), got {:?}", otherwise),
-        }
-        let _ = client.rpc(()); // Test whether second failure hangs
-    }
-
-    #[test]
-    fn concurrent() {
-        let _ = env_logger::init();
-        let concurrency = 10;
-        let pool = Pool::new(concurrency);
-        let server = Arc::new(BarrierServer::new(concurrency));
-        let serve_handle = server.clone().spawn("localhost:0").unwrap();
-        let addr = serve_handle.local_addr().clone();
-        let client: Client<(), u64> = Client::new(addr).unwrap();
-        pool.scoped(|scope| {
-            for _ in 0..concurrency {
-                let client = client.try_clone().unwrap();
-                scope.execute(move || {
-                    client.rpc(()).unwrap();
-                });
-            }
-        });
-        assert_eq!(concurrency as u64, server.count());
-        drop(client);
-        serve_handle.shutdown();
-    }
-
-    #[test]
-    fn async() {
-        let _ = env_logger::init();
-        let server = Arc::new(Server::new());
-        let serve_handle = server.spawn("localhost:0").unwrap();
-        let addr = serve_handle.local_addr().clone();
-        let client: Client<(), u64> = Client::new(addr).unwrap();
-
-        // Drop future immediately; does the reader channel panic when sending?
-        client.rpc_async(());
-        // If the reader panicked, this won't succeed
-        client.rpc_async(());
-
-        drop(client);
-        serve_handle.shutdown();
-    }
-}

tarpc/src/protocol/packet.rs

@@ -1,108 +0,0 @@
-use serde::{Deserialize, Deserializer, Serialize, Serializer, de, ser};
-use std::marker::PhantomData;
-
-/// Packet shared between client and server.
-#[derive(Debug, Clone, PartialEq, Eq, PartialOrd, Ord, Hash)]
-pub struct Packet<T> {
-    /// Packet id to map response to request.
-    pub rpc_id: u64,
-    /// Packet payload.
-    pub message: T,
-}
-
-const PACKET: &'static str = "Packet";
-const RPC_ID: &'static str = "rpc_id";
-const MESSAGE: &'static str = "message";
-
-impl<T: Serialize> Serialize for Packet<T> {
-    #[inline]
-    fn serialize<S>(&self, serializer: &mut S) -> Result<(), S::Error>
-        where S: Serializer
-    {
-        serializer.serialize_struct(PACKET,
-                                    MapVisitor {
-                                        value: self,
-                                        state: 0,
-                                    })
-    }
-}
-
-struct MapVisitor<'a, T: 'a> {
-    value: &'a Packet<T>,
-    state: u8,
-}
-
-impl<'a, T: Serialize> ser::MapVisitor for MapVisitor<'a, T> {
-    #[inline]
-    fn visit<S>(&mut self, serializer: &mut S) -> Result<Option<()>, S::Error>
-        where S: Serializer
-    {
-        match self.state {
-            0 => {
-                self.state += 1;
-                Ok(Some(try!(serializer.serialize_struct_elt(RPC_ID, &self.value.rpc_id))))
-            }
-            1 => {
-                self.state += 1;
-                Ok(Some(try!(serializer.serialize_struct_elt(MESSAGE, &self.value.message))))
-            }
-            _ => Ok(None),
-        }
-    }
-
-    #[inline]
-    fn len(&self) -> Option<usize> {
-        Some(2)
-    }
-}
-
-impl<T: Deserialize> Deserialize for Packet<T> {
-    #[inline]
-    fn deserialize<D>(deserializer: &mut D) -> Result<Self, D::Error>
-        where D: Deserializer
-    {
-        const FIELDS: &'static [&'static str] = &[RPC_ID, MESSAGE];
-        deserializer.deserialize_struct(PACKET, FIELDS, Visitor(PhantomData))
-    }
-}
-
-struct Visitor<T>(PhantomData<T>);
-
-impl<T: Deserialize> de::Visitor for Visitor<T> {
-    type Value = Packet<T>;
-
-    #[inline]
-    fn visit_seq<V>(&mut self, mut visitor: V) -> Result<Packet<T>, V::Error>
-        where V: de::SeqVisitor
-    {
-        let packet = Packet {
-            rpc_id: match try!(visitor.visit()) {
-                Some(rpc_id) => rpc_id,
-                None => return Err(de::Error::end_of_stream()),
-            },
-            message: match try!(visitor.visit()) {
-                Some(message) => message,
-                None => return Err(de::Error::end_of_stream()),
-            },
-        };
-        try!(visitor.end());
-        Ok(packet)
-    }
-}
-
-#[cfg(test)]
-extern crate env_logger;
-
-#[test]
-fn serde() {
-    use bincode;
-    let _ = env_logger::init();
-
-    let packet = Packet {
-        rpc_id: 1,
-        message: (),
-    };
-    let ser = bincode::serde::serialize(&packet, bincode::SizeLimit::Infinite).unwrap();
-    let de = bincode::serde::deserialize(&ser);
-    assert_eq!(packet, de.unwrap());
-}

tarpc/src/protocol/server.rs

@@ -1,264 +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;
-use scoped_pool::{Pool, Scope};
-use std::fmt;
-use std::io::{self, BufReader, BufWriter};
-use std::net::{SocketAddr, TcpListener, TcpStream, ToSocketAddrs};
-use std::sync::mpsc::{Receiver, Sender, TryRecvError, channel};
-use std::sync::atomic::{AtomicBool, Ordering};
-use std::time::Duration;
-use std::thread::{self, JoinHandle};
-use super::{Config, Deserialize, Error, Packet, Result, Serialize};
-
-struct ConnectionHandler<'a, S>
-    where S: Serve
-{
-    read_stream: BufReader<TcpStream>,
-    write_stream: BufWriter<TcpStream>,
-    server: S,
-    shutdown: &'a AtomicBool,
-}
-
-impl<'a, S> ConnectionHandler<'a, S>
-    where S: Serve
-{
-    fn handle_conn<'b>(&'b mut self, scope: &Scope<'b>) -> Result<()> {
-        let ConnectionHandler {
-            ref mut read_stream,
-            ref mut write_stream,
-            ref server,
-            shutdown,
-        } = *self;
-        trace!("ConnectionHandler: serving client...");
-        let (tx, rx) = channel();
-        scope.execute(move || Self::write(rx, write_stream));
-        loop {
-            match read_stream.deserialize() {
-                Ok(Packet { rpc_id, message, }) => {
-                    let tx = tx.clone();
-                    scope.execute(move || {
-                        let reply = server.serve(message);
-                        let reply_packet = Packet {
-                            rpc_id: rpc_id,
-                            message: reply,
-                        };
-                        tx.send(reply_packet).expect(pos!());
-                    });
-                    if shutdown.load(Ordering::SeqCst) {
-                        info!("ConnectionHandler: server shutdown, so closing connection.");
-                        break;
-                    }
-                }
-                Err(Error::Io(ref err)) if Self::timed_out(err.kind()) => {
-                    if !shutdown.load(Ordering::SeqCst) {
-                        info!("ConnectionHandler: read timed out ({:?}). Server not shutdown, so \
-                               retrying read.",
-                              err);
-                        continue;
-                    } else {
-                        info!("ConnectionHandler: read timed out ({:?}). Server shutdown, so \
-                               closing connection.",
-                              err);
-                        break;
-                    }
-                }
-                Err(e) => {
-                    warn!("ConnectionHandler: closing client connection due to {:?}",
-                          e);
-                    return Err(e.into());
-                }
-            }
-        }
-        Ok(())
-    }
-
-    fn timed_out(error_kind: io::ErrorKind) -> bool {
-        match error_kind {
-            io::ErrorKind::TimedOut | io::ErrorKind::WouldBlock => true,
-            _ => false,
-        }
-    }
-
-    fn write(rx: Receiver<Packet<<S as Serve>::Reply>>, stream: &mut BufWriter<TcpStream>) {
-        loop {
-            match rx.recv() {
-                Err(e) => {
-                    debug!("Write thread: returning due to {:?}", e);
-                    return;
-                }
-                Ok(reply_packet) => {
-                    if let Err(e) = stream.serialize(&reply_packet) {
-                        warn!("Writer: failed to write reply to Client: {:?}", e);
-                    }
-                }
-            }
-        }
-    }
-}
-
-/// Provides methods for blocking until the server completes,
-pub struct ServeHandle {
-    tx: Sender<()>,
-    join_handle: JoinHandle<()>,
-    addr: SocketAddr,
-}
-
-impl ServeHandle {
-    /// Block until the server completes
-    pub fn wait(self) {
-        self.join_handle.join().expect(pos!());
-    }
-
-    /// Returns the address the server is bound to
-    pub fn local_addr(&self) -> &SocketAddr {
-        &self.addr
-    }
-
-    /// Shutdown the server. Gracefully shuts down the serve thread but currently does not
-    /// gracefully close open connections.
-    pub fn shutdown(self) {
-        info!("ServeHandle: attempting to shut down the server.");
-        self.tx.send(()).expect(pos!());
-        if let Ok(_) = TcpStream::connect(self.addr) {
-            self.join_handle.join().expect(pos!());
-        } else {
-            warn!("ServeHandle: best effort shutdown of serve thread failed");
-        }
-    }
-}
-
-struct Server<'a, S: 'a> {
-    server: &'a S,
-    listener: TcpListener,
-    read_timeout: Option<Duration>,
-    die_rx: Receiver<()>,
-    shutdown: &'a AtomicBool,
-}
-
-impl<'a, S: 'a> Server<'a, S>
-    where S: Serve + 'static
-{
-    fn serve<'b>(self, scope: &Scope<'b>)
-        where 'a: 'b
-    {
-        for conn in self.listener.incoming() {
-            match self.die_rx.try_recv() {
-                Ok(_) => {
-                    info!("serve: shutdown received.");
-                    return;
-                }
-                Err(TryRecvError::Disconnected) => {
-                    info!("serve: shutdown sender disconnected.");
-                    return;
-                }
-                _ => (),
-            }
-            let conn = match conn {
-                Err(err) => {
-                    error!("serve: failed to accept connection: {:?}", err);
-                    return;
-                }
-                Ok(c) => c,
-            };
-            if let Err(err) = conn.set_read_timeout(self.read_timeout) {
-                info!("serve: could not set read timeout: {:?}", err);
-                continue;
-            }
-            let read_conn = match conn.try_clone() {
-                Err(err) => {
-                    error!("serve: could not clone tcp stream; possibly out of file descriptors? \
-                            Err: {:?}",
-                           err);
-                    continue;
-                }
-                Ok(conn) => conn,
-            };
-            let mut handler = ConnectionHandler {
-                read_stream: BufReader::new(read_conn),
-                write_stream: BufWriter::new(conn),
-                server: self.server,
-                shutdown: self.shutdown,
-            };
-            scope.recurse(move |scope| {
-                scope.zoom(|scope| {
-                    if let Err(err) = handler.handle_conn(scope) {
-                        info!("ConnectionHandler: err in connection handling: {:?}", err);
-                    }
-                });
-            });
-        }
-    }
-}
-
-impl<'a, S> Drop for Server<'a, S> {
-    fn drop(&mut self) {
-        debug!("Shutting down connection handlers.");
-        self.shutdown.store(true, Ordering::SeqCst);
-    }
-}
-
-/// A service provided by a server
-pub trait Serve: Send + Sync + Sized {
-    /// The type of request received by the server
-    type Request: 'static + fmt::Debug + serde::ser::Serialize + serde::de::Deserialize + Send;
-    /// The type of reply sent by the server
-    type Reply: 'static + fmt::Debug + serde::ser::Serialize + serde::de::Deserialize + Send;
-
-    /// Return a reply for a given request
-    fn serve(&self, request: Self::Request) -> Self::Reply;
-
-    /// spawn
-    fn spawn<A>(self, addr: A) -> io::Result<ServeHandle>
-        where A: ToSocketAddrs,
-              Self: 'static
-    {
-        self.spawn_with_config(addr, Config::default())
-    }
-
-    /// spawn
-    fn spawn_with_config<A>(self, addr: A, config: Config) -> io::Result<ServeHandle>
-        where A: ToSocketAddrs,
-              Self: 'static
-    {
-        let listener = try!(TcpListener::bind(&addr));
-        let addr = try!(listener.local_addr());
-        info!("spawn_with_config: spinning up server on {:?}", addr);
-        let (die_tx, die_rx) = channel();
-        let join_handle = thread::spawn(move || {
-            let pool = Pool::new(100); // TODO(tjk): make this configurable, and expire idle threads
-            let shutdown = AtomicBool::new(false);
-            let server = Server {
-                server: &self,
-                listener: listener,
-                read_timeout: config.timeout,
-                die_rx: die_rx,
-                shutdown: &shutdown,
-            };
-            pool.scoped(|scope| {
-                server.serve(scope);
-            });
-        });
-        Ok(ServeHandle {
-            tx: die_tx,
-            join_handle: join_handle,
-            addr: addr.clone(),
-        })
-    }
-
-}
-
-impl<P, S> Serve for P
-    where P: Send + Sync + ::std::ops::Deref<Target = S>,
-          S: Serve
-{
-    type Request = S::Request;
-    type Reply = S::Reply;
-
-    fn serve(&self, request: S::Request) -> S::Reply {
-        S::serve(self, request)
-    }
-}

tarpc/tests/latency.rs

@@ -0,0 +1,123 @@
+// 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,
+    integer_atomics,
+    futures_api,
+    generators,
+    await_macro,
+    async_await,
+    proc_macro_hygiene
+)]
+
+use futures::{compat::Executor01CompatExt, future, prelude::*};
+use libtest::stats::Stats;
+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(tokio::executor::DefaultExecutor::current().compat());
+
+    tokio::run(bench().map_err(|e| panic!(e.to_string())).boxed().compat())
+}

tarpc_examples/Cargo.toml

@@ -1,9 +0,0 @@
-[package]
-name = "tarpc_examples"
-version = "0.1.0"
-authors = ["Adam Wright <adam.austin.wright@gmail.com>", "Tim Kuehn <timothy.j.kuehn@gmail.com>"]
-
-[dev-dependencies]
-tarpc = { path = "../tarpc" }
-lazy_static = "^0.1.15"
-env_logger = "^0.3.2"

tarpc_examples/src/lib.rs

@@ -1,73 +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.
-
-#![cfg_attr(test, feature(test))]
-
-#[cfg(test)]
-#[macro_use]
-extern crate lazy_static;
-
-#[cfg(test)]
-#[macro_use]
-extern crate tarpc;
-
-#[cfg(test)]
-#[allow(dead_code)] // generated Client isn't used in this benchmark
-mod benchmark {
-    extern crate env_logger;
-    extern crate test;
-
-    use tarpc::ServeHandle;
-    use self::test::Bencher;
-    use std::sync::{Arc, Mutex};
-
-    service! {
-        rpc hello(s: String) -> String;
-    }
-
-    struct HelloServer;
-    impl Service for HelloServer {
-        fn hello(&self, s: String) -> String {
-            format!("Hello, {}!", s)
-        }
-    }
-
-    // Prevents resource exhaustion when benching
-    lazy_static! {
-        static ref HANDLE: Arc<Mutex<ServeHandle>> = {
-            let handle = HelloServer.spawn("localhost:0").unwrap();
-            Arc::new(Mutex::new(handle))
-        };
-        static ref CLIENT: Arc<Mutex<AsyncClient>> = {
-            let addr = HANDLE.lock().unwrap().local_addr().clone();
-            let client = AsyncClient::new(addr).unwrap();
-            Arc::new(Mutex::new(client))
-        };
-    }
-
-    #[bench]
-    fn hello(bencher: &mut Bencher) {
-        let _ = env_logger::init();
-        let client = CLIENT.lock().unwrap();
-        let concurrency = 100;
-        let mut futures = Vec::with_capacity(concurrency);
-        let mut count = 0;
-        bencher.iter(|| {
-            futures.push(client.hello("Bob".into()));
-            count += 1;
-            if count % concurrency == 0 {
-                // We can't block on each rpc call, otherwise we'd be
-                // benchmarking latency instead of throughput. It's also
-                // not ideal to call more than one rpc per iteration, because
-                // it makes the output of the bencher harder to parse (you have
-                // to mentally divide the number by `concurrency` to get
-                // the ns / iter for one rpc
-                for f in futures.drain(..) {
-                    f.get().unwrap();
-                }
-            }
-        });
-    }
-}

trace/Cargo.toml

@@ -0,0 +1,21 @@
+[package]
+name = "tarpc-trace"
+version = "0.2.0"
+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 = "0.6"
+
+[dependencies.serde]
+version = "1.0"
+optional = true
+features = ["derive"]

trace/rustfmt.toml

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

trace/src/lib.rs

@@ -0,0 +1,97 @@
+// 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(u128::from(rng.next_u64()) << mem::size_of::<u64>() | u128::from(rng.next_u64()))
+    }
+}
+
+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(())
+    }
+}