Function timeout_at

pub async fn timeout_at<F, T, E>(
    deadline: Instant,
    future: F,
) -> Result<T, TimeoutError<E>>
where
    F: Future<Output = Result<T, E>>,

Available on crate feature async only.

Applies a deadline to a Result-returning future.

Whether the deadline elapsed is indicated via the error type. Specifically:

• If future does not complete by deadline, returns TimeoutError::DeadlineElapsed.
• If future completes with Ok(t), returns Ok(t).
• If future completes with Err(e), returns TimeoutError::Inner(e).

Using this function can be considerably more readable than tokio::time::timeout_at when the inner future returns a Result.

Examples

use mz_ore::future::TimeoutError;
let slow_op = async {
    tokio::time::sleep(Duration::from_secs(1)).await;
    Ok::<_, String>(())
};
let deadline = Instant::now() + Duration::from_millis(1);
let res = mz_ore::future::timeout_at(deadline, slow_op).await;
assert_eq!(res, Err(TimeoutError::DeadlineElapsed));