Function fluvio_future::retry::retry_if

pub async fn retry_if<I, O, F, E, A, P>(
    retries: I,
    factory: A,
    condition: P
) -> Result<O, E>
where
    I: IntoIterator<Item = Duration>,
    A: FnMut() -> F,
    F: Future<Output = Result<O, E>>,
    P: Fn(&E) -> bool,
    E: Debug,

Provides retry functionality in async context. The Future that you want to retry needs to be represented in FnMut() -> Future structure. Each retry creates a new instance of Future and awaits it. Iterator Iterator<Item=Duration> controls the number of retries and delays between them. If iterator returns None, retries stop. There are three common implementations of retry strategies: FixedDelay, FibonacciBackoff, and ExponentialBackoff.

Example:

use std::io::{Error, ErrorKind};
use std::ops::AddAssign;
use std::time::Duration;
use fluvio_future::retry::FixedDelay;
use fluvio_future::retry::retry;

fluvio_future::task::run(async {
    let mut attempts = 0u8;
    let result = retry(FixedDelay::from_millis(100).take(2), || {
        attempts.add_assign(1);
        operation()
    }).await;
    assert!(matches!(result, Err(err) if err.kind() == ErrorKind::NotFound));
    assert_eq!(attempts, 3); // first attempt + 2 retries
});

async fn operation() -> Result<(), Error> {
    Err(Error::from(ErrorKind::NotFound))
}