Expand description
§Async Timeouts Helper
It is a simple instrument to delay execution of an async task with additional methods:
- reset timeout with a new value, i.e. to delay execution of your task;
- restart timeout with a new or previous task;
- stop the timer before your task will be executed;
- finished — check if the timer of the task is over or not.
It is convinient to use this crate with Notify or different channels (i.e. async_channel).
§Examples
Basic example
use std::time::{Duration, Instant};
use async_timeouts::Timeout;
use tokio::sync::Notify;
use std::sync::Arc;
#[tokio::main]
async fn main() {
let event = Arc::new(Notify::new());
let timer = Instant::now();
{
let event = event.clone();
// Let's notify our event after 3 seconds
Timeout::set(Duration::from_secs(3), async move {
event.notify_one();
}).await;
}
event.notified().await;
assert!(timer.elapsed().as_secs() >= 3);
println!("{} seconds elapsed", timer.elapsed().as_secs());
}If you do not need to start timer when Timeout is created, use Timeout::default() with
restart method
use std::time::Duration;
use async_timeouts::Timeout;
#[tokio::main]
async fn main() {
let mut task = Timeout::default();
println!("Task timer is not running yet: {}", task.finished());
assert!(task.finished());
task.restart(Duration::from_secs(3), async move {
// Some task here
tokio::time::sleep(Duration::from_secs(1)).await;
}).await;
println!("Task timer is running: {}", !task.finished());
assert!(!task.finished());
task.stop().await;
// Note, that you will not be notified instantly in async runtime after the `stop` command.
// But it takes runtime less than 1 nanosecond to do it in most cases.
println!("The 'finished()' method do not return 'true' instantly: {}", !task.finished());
tokio::time::sleep(Duration::from_nanos(1)).await;
println!("Task timer is stoped: {}", task.finished());
assert!(task.finished());
}