#concurrency #message #bus #queue

roundabout

An message oriented concurrent runtime

2 unstable releases

0.2.0 Jul 11, 2021
0.1.0 Jun 21, 2021

#149 in Concurrency

MIT/Apache

79KB
2K SLoC

Roundabout

<currently in an experimental state>

An message oriented concurrent runtime.

Roundabout uses a single message bus that is causal consistent for the whole program. This bus is then read in parallel by message handlers that can modify their internal state and send messages.

Cargo

To use roundabout in your project add the following to your Cargo.toml:

[dependencies]
roundabout = "0.2.0"

Hello World

use roundabout::prelude::*;

#[derive(Debug)]
pub struct PingEvent(u64);

#[derive(Debug)]
pub struct PongEvent(u64);

#[derive(Default)]
pub struct PingState {
    count: u64,
}

fn ping_handler(builder: OpenMessageHandlerBuilder<PingState>) -> InitMessageHandlerBuilder<PingState> {
    builder
        .on::<PingEvent>(|state, context, ping| {
            println!("Ping: {:?}", ping);
            context.sender().send(PongEvent(state.count));
            state.count += 1;
        })
        .init_default()
}

#[derive(Default)]
pub struct PongState {
    count: u64,
}

fn pong_handler(builder: OpenMessageHandlerBuilder<PongState>) -> InitMessageHandlerBuilder<PongState> {
    builder
        .on::<PongEvent>(|state, context, pong| {
            println!("Pong: {:?}", pong);
            state.count += 1;
            context.sender().send(PingEvent(state.count));
        })
        .init_default()
}

fn main() {
    Runtime::builder(512)
        .add(ping_handler)
        .add(pong_handler)
        .finish()
        .start(PingEvent(0));
}

Further steps

Take a look at the examples and benches.

Licence

Roundabout is dual-licensed under Apache 2.0 and MIT.

See LICENSE_APACHE and LICENSE_MIT

Dependencies

~1.5MB
~28K SLoC