The Queue System

Slow work, such as converting an uploaded video or sending a newsletter, shouldn't keep a user waiting. Put it in a queue: the request finishes at once, and a background worker does the job.

Workers run after a request's output is sent, so queues work without cron. Admins see the queues on the Dashboard.

The array is passed to the worker. A fourth argument delays the job by that many seconds.

Register it in _init():

jrCore_register_queue_worker('xxFoo', 'process_foo', 'xxFoo_process_foo_worker', 0, 1);

• 0: how many jobs one worker does before it stops. 0 is no limit; the default is 1.
• 1: how many workers may run this queue at once.
• Optional: a timeout (default 3600 seconds) and a priority from 1 to 9 (default 5).

The worker gets the job's data, and returns what happened:

function xxFoo_process_foo_worker($_queue)
{
    $_it = jrCore_db_get_item('xxFoo', $_queue['foo_id']);
    if (!$_it) {
        return true;      // nothing to do - delete the job
    }
    // ... do the work ...
    return true;          // done - delete the job
}

If a queue stops moving: pause the queues on the Dashboard, run an Integrity Check with Repair Modules checked, start the queues again, and reset the stuck queue.