nevsnode/backoff

Simple PHP Backoff Library

v1.3.0 2018-07-11 08:28 UTC

Requires

• php: >=5.6.0

Requires (Dev)

• phpunit/phpunit: 6.2.*

MIT

README

Very simple Backoff PHP library. It provides an easy solution to wait after failures with an increasing delay.

Install

composer require nevsnode/backoff

Example Usage

<?php
use nevsnode\Backoff;

$backoff = new Backoff();

$resource = new ExampleResource();
$result = $backoff->retryOnException(5, function () use ($resource) {
    $return = $resource->fetchSomething();
    if (!$return) {
        throw new Exception('Failed to fetch something');
    }
    return $return;
});

By default, when exceeding the number of retries, the last exception will just be thrown again. Optionally a final closure/value can be defined which is executed or returned instead:

<?php
$backoff = new nevsnode\Backoff();

// $result will now become the string "Some error"
$result = $backoff->retryOnException(3, function () {
    throw new \Exception('Some error');
}, function ($e) {
    return $e->getMessage();
});

// $result will now become FALSE
$result = $backoff->retryOnException(2, function () {
    throw new \Exception('Some error');
}, false);

Settings

Setting	Type	Default	Description
min	Integer	1000	Minimum delay (in ms)
max	Integer	30000	Maximum delay (in ms)
factor	Float	2.0	Multiplicator of delay on additional delays
jitter	Boolean	true	Allow jitter
jitterMax	Integer	2000	Maximum jitter (in ms)
exceptions	List of Strings	every Throwable/Exception	Specific list of exception-classes which will be retried

The settings can be passed as an associative array to the constructor and returned or adjusted after instantiation:

<?php

// pass settings to constructor
$backoff = new Backoff([
    'min' => 2000,
    'max' => 10000,
    'factor' => M_E,
]);

// define setting through setter
$backoff->setJitter(true);
$backoff->setJitterMax(6000);
$backoff->setMin(3000);

// return setting through getter
$max = $backoff->getMax();