Function tokio::time::interval

pub fn interval(period: Duration) -> Interval

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

An interval will tick indefinitely. At any time, the Interval value can be dropped. This cancels the interval.

This function is equivalent to interval_at(Instant::now(), period).

Panics

This function panics if period is zero.

Examples

use tokio::time::{self, Duration};

#[tokio::main]
async fn main() {
    let mut interval = time::interval(Duration::from_millis(10));

    interval.tick().await;
    interval.tick().await;
    interval.tick().await;

    // approximately 20ms have elapsed.
}

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

The difference between interval and delay_for 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 delay_for, 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() {
    println!("hello");
    time::delay_for(time::Duration::from_secs(1)).await
}

#[tokio::main]
async fn main() {
    let mut interval = time::interval(time::Duration::from_secs(2));
    for _i in 0..5 {
        interval.tick().await;
        task_that_takes_a_second().await;
    }
}