Module tokio::timer

Utilities for tracking time.

This module provides a number of types for executing code after a set period of time.

• Delay is a future that does no work and completes at a specific Instant in time.

• Interval is a stream yielding a value at a fixed period. It is initialized with a Duration and repeatedly yields each time the duration elapses.

• Timeout: Wraps a future or stream, setting an upper bound to the amount of time it is allowed to execute. If the future or stream does not complete in time, then it is canceled and an error is returned.

• DelayQueue: A queue where items are returned once the requested delay has expired.

These types are sufficient for handling a large number of scenarios involving time.

These types must be used from within the context of the Runtime or a timer context must be setup explicitly. See the tokio-timer crate for more details on how to setup a timer context.

Examples

Wait 100ms and print “Hello World!”

use tokio::prelude::*;
use tokio::timer::Delay;

use std::time::{Duration, Instant};

let when = Instant::now() + Duration::from_millis(100);

tokio::run({
    Delay::new(when)
        .map_err(|e| panic!("timer failed; err={:?}", e))
        .and_then(|_| {
            println!("Hello world!");
            Ok(())
        })
})

Require that an operation takes no more than 300ms. Note that this uses the timeout function on the FutureExt trait. This trait is included in the prelude.

use tokio::prelude::*;

use std::time::{Duration, Instant};

fn long_op() -> Box<Future<Item = (), Error = ()> + Send> {
    // ...
}

tokio::run({
    long_op()
        .timeout(Duration::from_millis(300))
        .map_err(|e| {
            println!("operation timed out");
        })
})

Modules

delay_queue

A queue of delayed elements.

timeout

Allows a future or stream to execute for a maximum amount of time.

Structs

Delay

A future that completes at a specified instant in time.

DelayQueue

A queue of delayed elements.

Error

Errors encountered by the timer implementation.

Interval

A stream representing notifications at fixed interval

Timeout

Allows a Future or Stream to execute for a limited amount of time.