backoff

The delay before retry number attempt, doubling each time up to max: exponential backoff.

Attempt 1 waits base, attempt 2 waits 2 × base, attempt 3 4 × base, and so on, never more than max. Attempt 0 is treated like attempt 1. The arithmetic saturates, so a huge attempt number gives max instead of overflowing. Nothing sleeps: the caller decides what to do with the duration (see retry).

Import

use helpers4::function::backoff;

Cargo feature function (enabled by default). To compile only this module:

cargo add helpers4 --no-default-features --features function

or in Cargo.toml:

[dependencies]
helpers4 = { version = "0.0.6", default-features = false, features = ["function"] }

Signature

pub fn backoff(attempt: u32, base: Duration, max: Duration) -> Duration

Parameters

Parameter	Type	Description
attempt	u32	The number of the attempt that just failed, starting at 1.
base	Duration	The delay after the first failure.
max	Duration	The longest delay to ever return.

Returns

Duration — The duration to wait, between base and max (or max alone if base is larger).

Examples

use helpers4::function::backoff;
use std::time::Duration;

let base = Duration::from_millis(100);
let max = Duration::from_secs(1);
assert_eq!(backoff(1, base, max), Duration::from_millis(100));
assert_eq!(backoff(3, base, max), Duration::from_millis(400));
assert_eq!(backoff(10, base, max), max);

Source

src/function/backoff.rs