Question

I'd like to在Rocket服务器旁边启动Tokio事件循环，然后稍后将事件添加到该循环中。我读过Is there a way to launch a tokio::Delay on a new thread to allow the main loop to continue?，但是我仍然不清楚如何实现自己的目标。

Answer 1

为the documentation states：

虽然current_thread::Runtime未实现Send并且不能安全地移动到其他线程，但是它提供了Handle可以发送到其他线程并允许从那里产生新任务。

这里是一个将事件循环放到一个线程中并让第二个线程生成任务的示例。所有任务均以交错的间隔开始，但同时完成：

use std::{
    thread,
    time::{Duration, Instant},
};
use tokio::{prelude::*, runtime::current_thread, timer::Delay}; // 0.1.15

fn main() {
    let (shutdown_tx, shutdown_rx) = tokio::sync::oneshot::channel();
    let (handle_tx, handle_rx) = std::sync::mpsc::channel();

    let tokio_thread = thread::spawn(move || {
        let mut runtime = current_thread::Runtime::new().expect("Unable to create the runtime");

        eprintln!("Runtime created");

        // Give a handle to the runtime to another thread.
        handle_tx
            .send(runtime.handle())
            .expect("Unable to give runtime handle to another thread");

        // Continue running until notified to shutdown
        runtime
            .spawn({ shutdown_rx.map_err(|e| panic!("Error on the shutdown channel: {:?}", e)) });

        // Finish all pending tasks
        runtime.run().expect("Unable to run the runtime");

        eprintln!("Runtime finished");
    });

    let another_thread = thread::spawn(move || {
        let handle = handle_rx
            .recv()
            .expect("Could not get a handle to the other thread's runtime");

        eprintln!("Another thread created");
        let two_seconds_after_creation = Instant::now() + Duration::from_secs(2);

        for value in 0..10 {
            // Run this future in the other thread's runtime
            handle
                .spawn(future::lazy(move || {
                    eprintln!("Starting task for value {}", value);

                    Delay::new(two_seconds_after_creation)
                        .inspect(move |_| eprintln!("Finishing task for value {}", value))
                        .map(drop)
                        .map_err(drop)
                }))
                .expect("Unable to spawn a new task on the runtime");

            thread::sleep(Duration::from_millis(100));
        }

        eprintln!("Another thread finished");
    });

    another_thread.join().expect("Another thread panicked");

    shutdown_tx
        .send(())
        .expect("Unable to shutdown runtime thread");

    tokio_thread.join().expect("Tokio thread panicked");
}

Runtime created
Another thread created
Starting task for value 0
Starting task for value 1
Starting task for value 2
Starting task for value 3
Starting task for value 4
Starting task for value 5
Starting task for value 6
Starting task for value 7
Starting task for value 8
Starting task for value 9
Another thread finished
Finishing task for value 0
Finishing task for value 1
Finishing task for value 2
Finishing task for value 3
Finishing task for value 4
Finishing task for value 5
Finishing task for value 6
Finishing task for value 7
Finishing task for value 8
Finishing task for value 9
Runtime finished

如何将任务添加到在另一个线程上运行的Tokio事件循环中？

1 个答案: