h1. Parallel processing in PHP with RabbitMQ

h2. Introduction

This is a very simple example on how to accomplish parallel processing with PHP by using the messaging application RabbitMQ.
See http://geekexmachina.com/2010/10/parallelizing-php-rabbitmq/ for more details.

h2. Requirements

- PHP 5.3
- RabbitMQ running on localhost (update the include.php file for connection setting)
- The library PHP-AMQPLIB from http://github.com/tnc/php-amqplib (update include.php for path to the library)

h2. Installation

In any folder, run this:

$ git clone http://github.com/elboby/ParallelExample
$ cd ParallelExample
$ git http://github.com/tnc/php-amqplib

h2. Run

In the ParallelExample folder:

- Launch first the 2 consumers in 2 separate terminals:

$ php consume.php a
$ php consume.php b

- In another terminal, launch the main script:

$ php run_parallel.php

h2. Output

If it works, you should see this in the consumer terminals:

$ php consume.php a
23:38:04: a : PHPPROCESS_24025 : start processing...
23:38:14: a : PHPPROCESS_24025 : done in 10 seconds!
^C

$ php consume.php b
23:38:04: b : PHPPROCESS_24025 : start processing...
23:38:09: b : PHPPROCESS_24025 : done in 5 seconds!
^C


And in the main terminal

$ php run_parallel.php 
23:38:04 : PHPPROCESS_24025 : waiting for responses...
array(2) {
  ["b"]=>
  string(15) "waited 5seconds"
  ["a"]=>
  string(16) "waited 10seconds"
}
23:38:14 : PHPPROCESS_24025 : done in 10.010743141174 seconds
$