## BackoffV2 
BackoffV2 is a PHP 5.5+ library implementing various backoff algorithms, such as exponential backoff., (*1)
This library only returns a backoff delay amount based on the selected algorithms; implementation of the actual delay mechanism (such as sleep()) is left to the user., (*2)
Installation
Install BackoffV2 with Composer:, (*3)
composer require patinthehat/backoffv2, (*4)
Implementation
"Jitter" is implemented, if you choose to use it. Jitter is a small, variable amount of time that is added to the backoff amount., (*5)
Available Jitter algorithms (roughly based on this post) include:, (*6)
- NoJitter - No jitter
- FullJitter - Standard jitter amount
- EqualJitter - More consistent jitter amounts
- DecorrelatedJitter - Higher jitter amounts
Backoff algorithms include:, (*7)
- ExponentialBackoff - exponentially increase the backoff amount
- ConstantBackoff - use the same backoff amount, regardless of the attempt count.
- LinearBackoff - linear increase of the backoff amount, i.e. 1, 2, 3, 4, ...
Usage
Using the Backoff class
BackoffV2 implements a main class, Backoff, that acts as a container and manager for the backoff and jitter algorithms you choose.
The constructor signature for Backoff is:, (*8)
public function __construct($maxBackoff, BackoffStrategyInterface $backoff, JitterStrategyInterface $jitter)
Usage is simple:, (*9)
include 'vendor/autoload.php';
use BackoffV2\Backoff;
use BackoffV2\Backoff\ExponentialBackoff;
use BackoffV2\Jitter\FullJitter;
$b = new Backoff(15, new ExponentialBackoff, new FullJitter);
echo 'backoff = '.$b->getBackoff() . PHP_EOL;
echo 'backoff = '.$b->getBackoff() . PHP_EOL;
echo 'backoff = '.$b->getBackoff() . PHP_EOL;
echo 'backoff = '.$b->getBackoff() . PHP_EOL;
echo 'backoff = '.$b->getBackoff() . ' (attempt ' . $b->getAttempt().')' . PHP_EOL;
$b->reset();
License
BackoffV2 is available under the MIT License., (*10)
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