Struct ExponentialBackoff 

pub struct ExponentialBackoff { /* private fields */ }

An exponential backoff strategy.

This backoff strategy provides backoff durations that increase exponentially based on a user-provided error count, with a minimum and maximum bound on the duration. Additionally, jitter can be added to the backoff duration in order to help avoiding multiple callers retrying their requests at the same time.

Implementations

impl ExponentialBackoff

pub fn new(min_backoff: Duration, max_backoff: Duration) -> Self

Creates a new ExponentialBackoff with the given minimum and maximum backoff durations.

Jitter is not applied to the calculated backoff durations.

pub fn with_jitter( min_backoff: Duration, max_backoff: Duration, min_backoff_factor: f64, ) -> Self

Creates a new ExponentialBackoff with the given minimum and maximum backoff durations, and minimum backoff factor.

Jitter is applied to the calculated backoff durations based on the minimum backoff factor, such that any given backoff duration will be between D/min_backoff_factor and D, where D is the calculated backoff duration for the given external error count. If the minimum backoff factor is set to 1.0 or less, then jitter will be disabled.

Concretely, this means that with a minimum backoff duration of 10ms, and a minimum backoff factor of 2.0, the duration for an error count of one would be 20ms without jitter, but anywhere between 10ms and 20ms with jitter. For an error count of two, it be 40ms without jitter, but anywhere between 20ms and 40ms with jitter.

pub fn with_rng<R>(self, rng: R) -> Self

where R: RngCore + Send + Sync + 'static,

Sets the random number generator to use for calculating jittered backoff durations.

Useful for testing purposes, where the RNG must be overridden to add determinism. The RNG is shared atomically behind a mutex, allowing it to be cloned, so care should be taken to never use this outside of tests.

Defaults to a lazily-initialized, thread-local CSPRNG seeded by the operating system.

pub fn get_backoff_duration(&mut self, error_count: u32) -> Duration

Calculates the backoff duration for the given error count.

The error count value is generally user-defined, but should constitute the number of consecutive errors, or attempts, that have been made when retrying an operation or request.

Trait Implementations

impl Clone for ExponentialBackoff

fn clone(&self) -> ExponentialBackoff

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for ExponentialBackoff

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.