time
only.Expand description
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 specificInstant
in time. -
Interval
is a stream yielding a value at a fixed period. It is initialized with aDuration
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
.
§Examples
Wait 100ms and print “100 ms have elapsed”
use std::time::Duration;
use tokio::time::sleep;
#[tokio::main]
async fn main() {
sleep(Duration::from_millis(100)).await;
println!("100 ms have elapsed");
}
Require that an operation takes no more than 1s.
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() {
println!("hello");
time::sleep(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;
}
}
Re-exports§
pub use std::time::Duration;
Modules§
- Time error types.
Structs§
- A measurement of a monotonically nondecreasing clock. Opaque and useful only with
Duration
. - Interval returned by
interval
andinterval_at
. - Future returned by
sleep
andsleep_until
. - Future returned by
timeout
andtimeout_at
.
Enums§
- Defines the behavior of an
Interval
when it misses a tick.
Functions§
- Creates new
Interval
that yields with interval ofperiod
. The first tick completes immediately. The defaultMissedTickBehavior
isBurst
, but this can be configured by callingset_missed_tick_behavior
. - Creates new
Interval
that yields with interval ofperiod
with the first tick completing atstart
. The defaultMissedTickBehavior
isBurst
, but this can be configured by callingset_missed_tick_behavior
. - Waits until
duration
has elapsed. - Waits until
deadline
is reached. - Requires a
Future
to complete before the specified duration has elapsed. - Requires a
Future
to complete before the specified instant in time.