Struct ExponentialBuilder 

pub struct ExponentialBuilder { /* private fields */ }

ExponentialBuilder is used to construct an [ExponentialBackoff] that offers delays with exponential retries.

Default

• jitter: false
• factor: 2
• min_delay: 1s
• max_delay: 60s
• max_times: 3

Examples

use anyhow::Result;
use backon::ExponentialBuilder;
use backon::Retryable;

async fn fetch() -> Result<String> {
    Ok(reqwest::get("https://www.rust-lang.org")
        .await?
        .text()
        .await?)
}

#[tokio::main(flavor = "current_thread")]
async fn main() -> Result<()> {
    let content = fetch.retry(ExponentialBuilder::default()).await?;
    println!("fetch succeeded: {}", content);

    Ok(())
}

Implementations

impl ExponentialBuilder

pub const fn new() -> ExponentialBuilder

Create a new ExponentialBuilder with default values.

pub const fn with_jitter(self) -> ExponentialBuilder

Enable jitter for the backoff.

When jitter is enabled, [ExponentialBackoff] will add a random jitter within (0, current_delay) to the current delay.

pub fn with_jitter_seed(self, seed: u64) -> ExponentialBuilder

Set the seed value for the jitter random number generator. If no seed is given, a random seed is used in std and default seed is used in no_std.

pub const fn with_factor(self, factor: f32) -> ExponentialBuilder

Set the factor for the backoff.

Note: Having a factor less than 1.0 does not make any sense as it would create a smaller negative backoff.

pub const fn with_min_delay(self, min_delay: Duration) -> ExponentialBuilder

Set the minimum delay for the backoff.

pub const fn with_max_delay(self, max_delay: Duration) -> ExponentialBuilder

Set the maximum delay for the backoff.

The delay will not increase if the current delay exceeds the maximum delay.

pub const fn without_max_delay(self) -> ExponentialBuilder

Set no maximum delay for the backoff.

The delay will keep increasing.

The delay will saturate at Duration::MAX which is an unrealistic delay.

pub const fn with_max_times(self, max_times: usize) -> ExponentialBuilder

Set the maximum number of attempts for the current backoff.

The backoff will stop if the maximum number of attempts is reached.

pub const fn without_max_times(self) -> ExponentialBuilder

Set no maximum number of attempts for the current backoff.

The backoff will not stop by itself.

The backoff could stop reaching usize::MAX attempts but this is unrealistic.

pub const fn with_total_delay( self, total_delay: Option<Duration>, ) -> ExponentialBuilder

Set the total delay for the backoff.

The backoff will stop yielding sleep durations once the cumulative sleep time plus the next sleep duration would exceed total_delay.

Trait Implementations

impl BackoffBuilder for ExponentialBuilder

type Backoff = ExponentialBackoff

The associated backoff returned by this builder.

fn build(self) -> <ExponentialBuilder as BackoffBuilder>::Backoff

Construct a new backoff using the builder.

impl BackoffBuilder for &ExponentialBuilder

type Backoff = ExponentialBackoff

The associated backoff returned by this builder.

fn build(self) -> <&ExponentialBuilder as BackoffBuilder>::Backoff

Construct a new backoff using the builder.

impl Clone for ExponentialBuilder

fn clone(&self) -> ExponentialBuilder

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Copy for ExponentialBuilder

impl Debug for ExponentialBuilder

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

Formats the value using the given formatter.

impl Default for ExponentialBuilder

fn default() -> ExponentialBuilder

Returns the “default value” for a type.