tebru/executioner

Provides a library for handling PHP exceptions when you would like to retry execution.

, _(*1)

Executioner

This library aims to create an easy way to execute code that may throw an exception and should be reattempted., _(*2)

Installation

Run composer require tebru/executioner:dev-master, _(*3)

Basic Usage

The library can be used as simply as this, _(*4)

<?php

use Tebru\Executioner;

$executor = new Executor();
$result = $executor->execute(2, function () { /* code that may throw an exception */ });

Which will retry twice on all exceptions. Failure to execute without throwing an exception will cause a \Tebru\Executioner\Exception\FailedException to be thrown. Be sure to wrap your execute() call in a try/catch if you do not want that exception to propagate., _(*5)

Events

Events are used to provides hooks/insight into the operations. The 4 events are:, _(*6)

• beforeAttempt
• afterAttempt
• failedAttempt
• endAttempt

This library uses the Symfony2 event dispatcher. Feel free to use the included subscribers or create your own., _(*7)

Use the listener methods on the Executor to target one event, and use subscribers to target multiple events., _(*8)

Delay between attempts

<?php

use Tebru\Executioner;
use Tebru\Executioner\Subscriber\WaitSubscriber;

$waitStrategy = new \Tebru\Executioner\Strategy\WaitStrategy();

$executor = new Executor();
$executor->addSubscriber(new WaitSubscriber($waitStrategy));
$result = $executor->execute(2, function () { /* code that may throw an exception */ });

There are two wait strategies included:, _(*9)

• Tebru\Executioner\Strategy\StaticWaitStrategy -- Waits for a set amount of time between each attempt
• Tebru\Executioner\Strategy\ExponentialBackoffStrategy -- On average, exponentially waits longer between each attempt

Logging

<?php

use Tebru\Executioner;
use Tebru\Executioner\Subscriber\LoggerSubscriber;

$logger = new \Psr\Log\LoggerInterface(); // the only requirement is you need a ps-3 compatible logger

$executor = new Executor();
$executor->addSubscriber(new LoggerSubscriber('name-of-this-logger-to-distinguish-it-in-the-logs', $logger));
$result = $executor->execute(2, function () { /* code that may throw an exception */ });

Retry on non-exceptions

<?php

use Tebru\Executioner;
use Tebru\Executioner\Subscriber\ReturnSubscriber;

$executor = new Executor();
$executor->addSubscriber(new ReturnSubscriber([false]));
$result = $executor->execute(2, function () { return false; });

Shortcuts

To make life easier, there are some helper methods to create some of the included subscribers, _(*10)

Add a LoggerSubscriber, _(*11)

Executor::addLogger($name, LoggerInterface $logger)

Add a WaitSubscriber using the StaticWaitStrategy, _(*12)

Executor::addWait($seconds)

Add a WaitSubscriber, _(*13)

Executor::addWaitStrategy(WaitStrategy $waitStrategy)