# 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!
# Open Questions
1. Should client.send() return `Future<Response>` or `Future<Future<Response>>`? The former appears more ergonomic but it doesn’t allow concurrent requests with a single client handle. The latter is less ergonomic but yields back control of the client once it’s successfully sent out the request. Should we offer fns for both?
2. Should rpc service! Fns take &mut self or &self or self? The service needs to impl Clone anyway, technically we only need to clone it once per connection, and then leave it up to the user to decide if they want to clone it per RPC. In practice, everyone doing nontrivial stuff will need to clone it per RPC, I think.
3. Do the request/response structs look ok?
4. Is supporting server shutdown/lameduck important?
Fixes#178#155#124#104#83#38
* Rewrite tarpc on top of tokio.
* Add examples
* Move error types to their own module.
Also, cull unused error variants.
* Remove unused fn
* Remove CanonicalRpcError* types. They're 100% useless.
* Track tokio master (WIP)
* The great error revamp.
Removed the canonical rpc error type. Instead, the user declares
the error type for each rpc:
In the above example, the error type is Baz. Declaring an error is
optional; if none is specified, it defaults to Never, a convenience
struct that wraps the never type (exclamation mark) to impl Serialize, Deserialize,
Error, etc. Also adds the convenience type StringError for easily
using a String as an error type.
* Add missing license header
* Minor cleanup
* Rename StringError => Message
* Create a sync::Connect trait.
Along with this, the existing Connect trait moves to future::Connect. The future
and sync modules are reexported from the crate root.
Additionally, the utility errors Never and Message are no longer reexported from
the crate root.
* Update readme
* Track tokio/futures master. Add a Spawn utility trait to replace the removed forget.
* Fix pre-push hook
* Add doc comment to SyncServiceExt.
* Fix up some documentation
* Track tokio-proto master
* Don't set tcp nodelay
* Make future::Connect take an associated type for the future.
* Unbox FutureClient::connect return type
* Use type alias instead of newtype struct for ClientFuture
* Fix benches/latency.rs
* Write a plugin to convert lower_snake_case idents/types to UpperCamelCase.
Use it to add associated types to FutureService instead of boxing the return futures.
* Specify plugin = true in snake_to_camel/Cargo.toml. Weird things happen otherwise.
* Add clippy.toml
