Sometimes we need to queue things without messing around with queue servers because we have a smaller scale. Sometimes we have a larger scale but don't want the overhead of extra services, and the things we queue are few. Regardless, this module is a database-based queue manager that can be used to asynchronously flush things like order exports, reports generation, and so on.
- Runs via crontab as an ordinary Magento cron job
- Uses locking to prevent parallell queue execution
- Lock classes are pluggable, the default one uses directories doesn't scale
- Can be enabled/disabled in System / Configuration
- Supports batches (default 100 jobs per run)
- Uses traits, which lets you plug deferrability into your classes of choice
- Queue namespacing
- Jobs that fail with a recoverable error (such as an I/O error), can be retried until succesful
First, install the module. Second, enable the standard Magento cron job. After that, all you need to do is have a look at the Example class in the Model/Job directory:
<?php
/**
* Example job
*/
class Made_Queue_Model_Job_Example implements Made_Queue_Model_Job_Interface
{
use Deferrable;
protected $_message;
/**
* The worker runs perform on the unserialized job instance
*/
public function perform()
{
echo $this->_message . "\n";
}
/**
* Just a setter
*
* @param $message
*/
public function setMessage($message)
{
$this->_message = $message;
}
/**
* String representation of object
* @return string the string representation of the object or null
*/
public function serialize()
{
return serialize($this->_message);
}
/**
* The string representation of the object.
*
* @return void
*/
public function unserialize($serialized)
{
$this->_message = unserialize($serialized);
}
}Key in this code is "use Deferrable;" and "perform()". The trait adds the defer() method to the class which when called creates a job and adds it to the queue for execution. The queue manager runs the "perform()" method on an unserialized version of the class. A class can defer itself, like this:
<?php
$job = new Made_Queue_Model_Job_Example();
$job->setMessage('lol');
$job->defer();There are two optional arguments for defer() - $queue and $numRetries. $queue is used for queue namespacing. $numRetries determines how many times we should retry a recoverable error (default 1).
Some jobs fail fatally, some fail temporarily. To differentiate between these two there is an Made_Queue_Model_Job_RecoverableException class your job can throw if it needs to be retried. All other exceptions will be treated as fatal and these jobs won't be retried.
The future might implement a pluggable queue daemon interface for us, and just keep the ease of queueability in this module