[][src]Module tokio::time

This is supported on crate feature time only.

Utilities for tracking time.

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

  • Sleep 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.

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.


Wait 100ms and print "100 ms have elapsed"

use tokio::time::sleep;

use std::time::Duration;

async fn main() {
    println!("100 ms have elapsed");

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::time::{timeout, Duration};

async fn long_future() {
    // do work here

let res = timeout(Duration::from_secs(1), long_future()).await;

if res.is_err() {
    println!("operation timed out");

A simple example using interval to execute a task every two seconds.

The difference between interval and sleep is that an interval measures the time since the last tick, which means that .tick().await may wait for a shorter time than the duration specified for the interval if some time has passed between calls to .tick().await.

If the tick in the example below was replaced with sleep, the task would only be executed once every three seconds, and not every two seconds.

use tokio::time;

async fn task_that_takes_a_second() {

async fn main() {
    let mut interval = time::interval(time::Duration::from_secs(2));
    for _i in 0..5 {


pub use std::time::Duration;



Time error types.



A measurement of a monotonically nondecreasing clock. Opaque and useful only with Duration.


Stream returned by interval and interval_at.


Future returned by sleep and sleep_until.


Future returned by timeout and timeout_at.


advancetime and test-util

Advance time


Creates new Interval that yields with interval of duration. The first tick completes immediately.


Creates new Interval that yields with interval of period with the first tick completing at start.

pausetime and test-util

Pause time

resumetime and test-util

Resume time


Waits until duration has elapsed.


Waits until deadline is reached.


Require a Future to complete before the specified duration has elapsed.


Require a Future to complete before the specified instant in time.