Thrust

Note: A work in progress. It's not in a useful state right now.

A Rust implementation of the Apache Thrift protocol that simplifies communicating between independent systems that may be implemented in various languages.

Features

Scalable Thrift RPC
Rust code generator from a .thrift file.
Built on-top of Asynchronous I/O via Mio.
Heavily uses Futures to manage asynchronous code.
Multiplexing multiple RPC services on a single event-loop.
(Currently limited to one for now) Automatically spawn an EventLoop per CPU core.

Installing

[dependencies]
thrust = "*"

You may also want to install the code generator using Cargo:

cargo install thrust

Generating Rust Code

Thrust comes with a thrust binary that compiles your .thrift files into Rust code.

thrust hello.thrift .

The first argument is the input thrift file and the second is the path where you want your Rust file to be written to. The filename will be based on the Rust namespace in your thrift file namespace rust <name>.

Spawning The Reactor

All the I/O and networking is built using Mio. By default, a single Reactor is spun up globally. Support for multiple event loops/Reactors are supported but not working correctly right now.

use thrust::Reactor;

fn main() {
  // Run the reactor that multiplexes many clients and servers.
  Reactor::run();
}

Creating a Thrift Service

Thrust supports creating Thrift services, backed by non-blocking TCP sockets with Mio.

namespace rust thrift;
// Start by defining a service in your Thrift file.
service Flock {
  bool isLoggedIn(1: string token);
}

After using Thrust to generate the service in Rust, we can start using it.

extern crate thrust;
// Tangle is a futures implementation
extern crate tangle;

// The generated Rust module.
use thrift::Flock;

use thrust::{Reactor, Server};
use tangle::{Future, Async};

pub struct FlockService;

impl Flock for FlockService {
  fn isLoggedIn(&mut self, token: String) -> Future<bool> {
    if &*token == "123" {
      Async::Ok(true)
    } else {
      Async::Ok(false)
    }
  }
}

fn main() {
  let addr: SocketAddr = "127.0.0.1:7899".parse().unwrap();

  // Asynchronously bind the server to the specified port. This does
  // not block the current thread.
  Server::new(FlockService).bind(addr);

  // Run the Reactor with the server.
  Reactor::run();
}

Connecting to a Service

A client is automatically generated for each service you define in your .thrift file. Let's keep using our previously defined service as an example.

extern crate thrust;
// Tangle is a futures implementation
extern crate tangle;

// The generated Rust module.
use thrift::{Flock, Client};

use thrust::Reactor;
use tangle::{Future, Async};

fn main() {
  let addr: SocketAddr = "127.0.0.1:7899".parse().unwrap();

  // Connect to the service
  let flock = Client::connect(addr);

  // Initiate an RPC call
  flock.isLoggedIn("123").and_then(move |is| {
    if is == true {
      println!("You're logged in!")
    } else {
      println!("Nada");
    }

    Async::Ok(())
  });

  // Just as before, running the Reactor is required.
  Reactor::run();
}

Remember, Thrust is built using asynchronous primitives and futures are currently the common language for asynchronous tasks. Futures prevent much of the problems in traditional callback-based systems.

enum Error {
  AccessDenied
}

flock.isLoggedIn("123").and_then(move |is_logged_in| {
  if is_logged_in == true {
    Async::Ok(())
  } else {
    Async::Err(Error::AccessDenied)
  }
}).and_then(move || {
  // This will only run if the user has been logged in. Errors
  // can be caught later on.

  // ... Do some other fun stuff here.
  Async::Ok(())
}).error(move |err| {
  Async::Err(err)
})

Sharing Clients

You might want to share clients across threads and that's perfectly supported! Clients are fully clone-able and are thread-safe.

let shared = client.clone();

thread::spawn(move || {
  shared...
})

This will re-use the same connection underneath. All TCP connections run in a single Mio event loop (baring multiple event loops). If you wish to use multiple connections, you may create a new client.

License

MIT — go ham!

thehydroimpulse / thrust