simple-actor

Provides an Actor type that wraps a state and allows mutating it in turns using invoke.

Example

It is recommended to create a wrapper type around the Actor, and implement async functions that use invoke to interact with the inner private state.

use simple_actor::Actor;

#[derive(Clone)]
pub struct Adder(Actor<u32>);

impl Adder {
    pub fn new(initial_value: u32) -> Self {
        let (actor, driver) = Actor::new(initial_value);
        tokio::spawn(driver);
        Self(actor)
    }

    pub async fn add(&self, x: u32) {
        let _ = self.0.invoke(move |state| *state += x).await;
    }

    pub async fn result(&self) -> Option<u32> {
        self.0.invoke(move |state| *state).await
    }

    pub fn shutdown(&self) {
        self.0.shutdown()
    }
}

#[tokio::main]
async fn main() {
    let adder = Adder::new(5);

    adder.add(3).await;
    assert_eq!(adder.result().await, Some(8));

    adder.add(2).await;
    assert_eq!(adder.result().await, Some(10));

    adder.shutdown();
    assert_eq!(adder.result().await, None);
}

Inspiration

This crate is inspired by ghost_actor, with a simpler implementation and API. This crate invoke function returns None if the actor is down, which avoids dealing with error type conversions.