socloz/event-queue-bundle

A Symfony2 bundle that enable asynchonous execution of event listeners.

SoclozEventQueueBundle

A Symfony2 bundle that enable asynchonous execution of event listeners., _(*1)

As long as some conditions are met, no code changes are required for an application to use the bundle., _(*2)

The bundle is made of two parts : a listener and a worker., _(*3)

The listener : * is registered for the configured event, with maximum priority, * stops propagation of those events, * sends the serialized events to the queue., _(*4)

The worker : * builds the list of application listeners for the configured event, * listens to the queue and deserializes received events, * executes the listeners., _(*5)

Dependencies

• beanstalk - other queues can be added

Setup

• enable the bundle,, _(*6)

• install Socket_Beanstalk (http://github.com/davidpersson/beanstalk) in your vendors directory and configure autoload, _(*7)

$loader->registerPrefixes(array(
    [...]
    'Socket_'          => __DIR__.'/../vendor/beanstalk/src',
));

• configure the service

socloz_event_queue:
    queue_type: beanstalkd
    forward: [ my.event.name, my.event.name ]
    serialize: mongoodm
    beanstalkd:
        host: 127.0.0.1
        tube: event_queue

Other possible configuration options (with default values) :, _(*8)

socloz_event_queue:
    beanstalkd:
        port: 11300
        persistent: true
        timeout: 1

• start the worker (a process management daemon, like supervisord is recommended) :

$ app/console socloz:event_queue:worker [stop_after]

If used, stop_after enables to worker to stop after a certain number of seconds (warning : the test is done after a job has been executed)., _(*9)

Serializers

Events need to be serialized before being sent. Objects coming from the ORM/ODM usually cannot be serialized/deserialized using PHP builtin classes, therefore the bundle uses dedicated serializers., _(*10)

For now, 2 basic serializers exist :, _(*11)

• Mandango (serialize: mandango),
• MongoDB ODM (serialize: mongoodm).

They assume :, _(*12)

• that a getId method exists for ORM/ODM objects,
• that all objects having a getId method come from the ORM/ODM,
• that objects have been saved before dispatching the event (the remote listener instantiates objects from the DB),
• that events can be created using the constructor without other method calls,
• that constructor parameters have the same name as class attributes.

I did not have time/wasn't able to find a solution for those. Feel free to contribute better serializers !, _(*13)

ReflectionClass::newInstanceWithoutConstructor would help, but has only be added in 5.4. Class specific serializers, built during warm-up, would also improve performance if you need to forward a lot of events., _(*14)

Example event class :, _(*15)

<?php

namespace Socloz\APIBundle\Event\Event;

use Symfony\Component\EventDispatcher\Event;

class CategoryDeleteEvent extends Event
{
    protected $category;

    public function __construct($category)
    {
        $this->category = $category;
    }

    public function getCategory()
    {
        return $this->category;
    }
}

If you need a serializer, it needs to implement the Socloz\EventQueueBundle\Serialize\SerializeInterface interface., _(*16)

interface SerializeInterface
{
    public function serialize($event);

    public function deserialize($data);
}

It then needs to be registered as a service named socloz_event_queue.serialize.your_serializer_name and configured :, _(*17)

socloz_event_queue:
    serialize: your_serializer_name

Queue

If you want to use another transport (RabbitMQ, Zer0MQ, Gearman, ...), you need to implement the Socloz\EventQueueBundle\Queue\QueueInterface interface., _(*18)

interface QueueInterface
{
    public function put($job);

    public function get();

    public function delete($job);
}

get is a blocking call. delete is only required if get does not remove jobs from the queue., _(*19)

The transport class should be registered as a service named socloz_event_queue.queue., _(*20)

TODO

• Serializers I wouldn't be ashamed of
• Beanstalkd timeout & priority configuration

License

This bundle is released under the MIT license (see LICENSE)., _(*21)