PHP-Queue

A unified front-end for different queuing backends. Includes a REST server, CLI interface and daemon runners.

Why PHP-Queue?

Implementing a queueing system (eg. Beanstalk, Amazon SQS, RabbitMQ) for your application can be painful:

• Which one is most efficient? Performant?
• Learning curve to effectively implement the queue backend & the libraries.
• Time taken to develop the application codes.
• Vendor locked in, making it impossible to switch.
• Requires massive code change (ie. not flexible) when use case for the queue changes.

PHP-Queue hopes to serve as an abstract layer between your application code and the implementation of the queue.

Benefits

• Job Queue is Backend agnostic

  Just refer to the queue by name, what it runs on is independent of the application code. Your code just asks for the next item in the PHPQueue\JobQueue, and you'll get a PHPQueue\Job object with the data and jobId.

• Flexible Job Queue implementation

  You can decide whether each PHPQueue\JobQueue only carries 1 type of work or multiple types of target workers. You control the retrieval of the job data from the Queue Backend and how it is instantiated as a PHPQueue\Job object. Each PHPQueue\Job object carries information on which workers it is targeted for.

• Independent Workers

  Workers are independent of Job Queues. All it needs to worry about is processing the input data and return the resulting data. The queue despatcher will handle the rest. Workers will also be chainable.

• Powerful

  The framework is deliberately open-ended and can be adapted to your implementation. It doesn't get in the way of your queue system.

  We've build a simple REST server to let you post job data to your queue easily. We also included a CLI interface for adding and triggering workers. All of which you can sub-class and overwrite.

  You can also include our core library files into your application and do some powerful heavy lifting.

  Several backend drivers are bundled:

  • Memcache
  • Redis
  • MongoDB
  • CSV These can be used as the primary job queue server, or for abstract FIFO or key-value data access.

Installation

Installing via Composer

Composer is a dependency management tool for PHP that allows you to declare the dependencies your project needs and installs them into your project. In order to use the PHP-Queue through Composer, you must do the following:

1. Add "coderkungfu/php-queue" as a dependency in your project's composer.json file. Visit the Packagist page for more details.

2. Download and install Composer.

curl -s "http://getcomposer.org/installer" | php

3. Install your dependencies.

php composer.phar install

4. All the dependencies should be downloaded into a vendor folder.

5. Require Composer's autoloader.

<?php
require_once '/path/to/vendor/autoload.php';
?>

Getting Started

You can have a look at the Demo App inside .\vendor\coderkungfu\php-queue\src\demo\ folder for a recommended folder structure.

• htdocs folder
  • .htaccess
  • index.php
• queues folder
  • <QueueNameInCamelCase>Queue.php
• workers folder
  • <WorkerNameInCamelCase>Worker.php
• runners folder
• cli.php file
• config.php file

I would also recommend putting the autoloader statement and your app configs inside a separate config.php file.

Recommended config.php file content:

<?php
require_once '/path/to/vendor/autoload.php';
PHPQueue\Base::$queue_path = __DIR__ . '/queues/';
PHPQueue\Base::$worker_path = __DIR__ . '/workers/';
?>

Altenative config.php file:

You can also declare your application's namespace for loading the Queues and Workers.

<?php
require_once '/path/to/vendor/autoload.php';
PHPQueue\Base::$queue_namespace = '\MyFabulousApp\Queues';
PHPQueue\Base::$worker_namespace = '\MyFabulousApp\Workers';
?>

PHP-Queue will attempt to instantiate the PHPQueue\JobQueue and PHPQueue\Worker classes using your namespace - appended with the queue/worker name. (ie. \MyFabulousApp\Queues\Facebook).

It might be advisable to use Composer's Custom Autoloader for this.

Note:
If you declared PHPQueue\Base::$queue_path and/or PHPQueue\Base::$worker_path together with the namespace, the files will be loaded with require_once from those folder path AND instantiated with the namespaced class names.

REST Server

The default REST server can be used to interface directly with the queues and workers.

Copy the htdocs folder in the Demo App into your installation. The index.php calls the \PHPQueue\REST::defaultRoutes() method - which prepares an instance of the Respect\Rest REST server. You might need to modify the path of config.php within the index.php file.

Recomended installation: use a new virtual host and map the htdocs as the webroot.

1. Add new job.

# Form post
curl -XPOST http://localhost/<QueueName>/ -d "var1=foo&var2=bar"

# JSON post
curl -XPOST http://localhost/<QueueName>/ -H "Content-Type: application/json" -d '{"var1":"foo","var2":"bar"}'

2. Trigger next job.

curl -XPUT http://localhost/<QueueName>/

Read the full documentation on Respect\Rest to further customize to your application needs (eg. Basic Auth).

Command Line Interface (CLI)

Copy the cli.php file from the Demo App into your installation. This file implements the \PHPQueue\Cli class. You might need to modify the path of config.php within the cli.php file.

1. Add new job.

$ php cli.php <QueueName> add --data '{"boo":"bar","foo":"car"}'

2. Trigger next job.

$ php cli.php <QueueName> work

You can extend the PHPQueue\Cli class to customize your own CLI batch jobs (eg. import data from a MySQL DB into a queue).

Runners

You can read more about the Runners here.

Interfaces

The queue backends will support one or more of these interfaces:

• AtomicReadBuffer

This is the recommended way to consume messages. AtomicReadBuffer provides the popAtomic($callback) interface, which rolls back the popped record if the callback returns by exception. For example: $queue = new PHPQueue\Backend\PDO($options);

$queue->popAtomic(function ($message) use ($processor) {
    $processor->churn($message);
});

The message will only be popped if churn() returns successfully.

• FifoQueueStore

A first in first out queue accessed by push and pop.

License

This software is released under the MIT License.

Copyright (C) 2012 Michael Cheng Chi Mun

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.