Crate relentless 

relentless — a Rust library for retrying fallible operations and polling for conditions.

This crate provides composable retry strategies with support for std, alloc, and no_std environments.

Custom wait strategies

use core::time::Duration;
use relentless::{RetryState, Wait, wait};

struct CustomWait(Duration);

impl Wait for CustomWait {
    fn next_wait(&self, _state: &RetryState) -> Duration {
        self.0
    }
}

let strategy = CustomWait(Duration::from_millis(20))
    .cap(Duration::from_millis(15))
    .chain(wait::fixed(Duration::from_millis(50)), 2);

let state = RetryState::new(3, None);
assert_eq!(strategy.next_wait(&state), Duration::from_millis(50));

Extension-first usage

In sync std builds, .sleep(...) is optional because relentless falls back to std::thread::sleep. The example below still calls .sleep(...) so it compiles under no_std documentation test runs too.

use core::time::Duration;
use relentless::{RetryExt, stop, wait};

let result = (|| Err::<u32, &str>("transient"))
    .retry()
    .stop(stop::attempts(3))
    .wait(wait::fixed(Duration::from_millis(5)))
    .sleep(|_dur| {})
    .call();

assert!(result.is_err());

Re-exports

pub use predicate::Predicate;

pub use sleep::Sleeper;

pub use stop::Stop;

pub use wait::Wait;

Modules

predicate

Predicate trait and built-in retry predicate factories.

sleep

stop

Stop trait and built-in stop strategies.

wait

Wait trait and built-in wait strategies.

Structs

AsyncRetry

Async retry execution object.

AsyncRetryBuilder

Owned async retry builder created from AsyncRetryExt::retry_async.

AsyncRetryBuilderWithStats

Owned async retry builder wrapper that returns statistics.

AsyncRetryWithStats

Async retry execution wrapper that returns statistics.

AttemptState

Read-only context passed to the after_attempt hook.

ExitState

Final read-only context passed to the on_exit hook.

RetryPolicy

Reusable retry configuration.

RetryState

Non-generic retry context passed to Stop::should_stop, Wait::next_wait, the operation, and the before_attempt hook.

RetryStats

Aggregate statistics for a completed retry execution.

SyncRetry

Sync retry execution object.

SyncRetryBuilder

Owned sync retry builder created from RetryExt::retry.

SyncRetryBuilderWithStats

Owned sync retry builder wrapper that returns statistics.

SyncRetryWithStats

Sync retry execution wrapper that returns statistics.

Enums

RetryError

Error returned when a retry loop terminates without producing an accepted result.

StopReason

Why a retry loop terminated.

Traits

AsyncRetryExt

Extension trait to start async retries directly from a closure/function.

RetryExt

Extension trait to start sync retries directly from a closure/function.

Functions

retry

Returns a SyncRetryBuilder with default policy: attempts(3), exponential(100ms), any_error().

retry_async

Returns an AsyncRetryBuilder with default policy: attempts(3), exponential(100ms), any_error().

Type Aliases

DefaultAsyncRetryBuilder

Alias for the default owned async retry builder returned by AsyncRetryExt::retry_async.

DefaultAsyncRetryBuilderWithStats

Alias for the default owned async retry builder-with-stats returned by calling .with_stats() on AsyncRetryExt::retry_async.

DefaultSyncRetryBuilder

Alias for the default owned sync retry builder returned by RetryExt::retry.

DefaultSyncRetryBuilderWithStats

Alias for the default owned sync retry builder-with-stats returned by calling .with_stats() on RetryExt::retry.

RetryResult

Convenience alias: Result<T, RetryError<T, E>>.