<?php
/* -*- tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
/*
# ***** BEGIN LICENSE BLOCK *****
# This file is part of InDefero, an open source project management application.
# Copyright (C) 2008-2011 CĂ©ondo Ltd and contributors.
#
# InDefero is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# InDefero is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
n# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
#
# ***** END LICENSE BLOCK ***** */
/**
* Queue system for the management of asynchronous operations.
*
* Anybody can add an item to the queue and any application can
* register itself to process an item from the queue.
*
* An item in the queue is considered as fully processed when all the
* handlers have processed it successfully.
*
* To push a new item in the queue:
*
* <code>
* $item = new IDF_Queue();
* $item->type = 'new_commit';
* $item->payload = array('what', 'ever', array('data'));
* $item->create();
* </code>
*
* To process one item from the queue, you first need to register an
* handler, by adding the following in your relations.php file before
* the return statement or in your config file.
*
* <code>
* Pluf_Signal::connect('IDF_Queue::processItem',
* array('YourApp_Class', 'processItem'));
* </code>
*
* The processItem method will be called with two arguments, the first
* is the name of the signal ('IDF_Queue::processItem') and the second
* is an array with:
*
* <code>
* array('item' => $item,
* 'res' => array('OtherApp_Class::handler' => false,
* 'FooApp_Class::processItem' => true));
* </code>
*
* When you process an item, you need first to check if the type is
* corresponding to what you want to work with, then you need to check
* in 'res' if you have not already processed successfully the item,
* that is the key 'YourApp_Class::processItem' must be set to true,
* and then you can process the item. At the end of your processing,
* you need to modify by reference the 'res' key to add your status.
*
* All the data except for the type is in the payload, this makes the
* queue flexible to manage many different kind of tasks.
*
*/
class IDF_Queue extends Pluf_Model
{
public $_model = __CLASS__;
function init()
{
$this->_a['table'] = 'idf_queue';
$this->_a['model'] = __CLASS__;
$this->_a['cols'] = array(
// It is mandatory to have an "id" column.
'id' =>
array(
'type' => 'Pluf_DB_Field_Sequence',
'blank' => true,
),
'status' =>
array(
'type' => 'Pluf_DB_Field_Integer',
'blank' => false,
'choices' => array(
'pending' => 0,
'in_progress' => 1,
'need_retry' => 2,
'done' => 3,
'error' => 4,
),
'default' => 0,
),
'trials' =>
array(
'type' => 'Pluf_DB_Field_Integer',
'default' => 0,
),
'type' =>
array(
'type' => 'Pluf_DB_Field_Varchar',
'blank' => false,
'size' => 50,
),
'payload' =>
array(
'type' => 'Pluf_DB_Field_Serialized',
'blank' => false,
),
'results' =>
array(
'type' => 'Pluf_DB_Field_Serialized',
'blank' => false,
),
'lasttry_dtime' =>
array(
'type' => 'Pluf_DB_Field_Datetime',
'blank' => true,
),
'creation_dtime' =>
array(
'type' => 'Pluf_DB_Field_Datetime',
'blank' => true,
),
);
}
function preSave($create=false)
{
if ($create) {
$this->creation_dtime = gmdate('Y-m-d H:i:s');
$this->lasttry_dtime = gmdate('Y-m-d H:i:s');
$this->results = array();
$this->trials = 0;
$this->status = 0;
}
}
/**
* The current item is going to be processed.
*/
function processItem()
{
/**
* [signal]
*
* IDF_Queue::processItem
*
* [sender]
*
* IDF_Queue
*
* [description]
*
* This signal allows an application to run an asynchronous
* job. The handler gets the queue item and the results from
* the previous run. If the handler key is not set, then the
* job was not run. If set it can be either true (already done)
* or false (error at last run).
*
* [parameters]
*
* array('item' => $item, 'res' => $res)
*
*/
$params = array('item' => $this, 'res' => $this->results);
Pluf_Signal::send('IDF_Queue::processItem',
'IDF_Queue', $params);
$this->status = 3; // Success
foreach ($params['res'] as $handler=>$ok) {
if (!$ok) {
$this->status = 2; // Set to need retry
$this->trials += 1;
break;
}
}
$this->results = $params['res'];
$this->lasttry_dtime = gmdate('Y-m-d H:i:s');
$this->update();
}
/**
* Parse the queue.
*
* It is a signal handler to just hook itself at the right time in
* the cron job performing the maintainance work.
*
* The processing relies on the fact that no other processing jobs
* must run at the same time. That is, your cron job must use a
* lock file or something like to not run in parallel.
*
* The processing is simple, first get 500 queue items, mark them
* as being processed and for each of them call the processItem()
* method which will trigger another event for processing.
*
* If you are processing more than 500 items per batch, you need
* to switch to a different solution.
*
*/
public static function process($sender, &$params)
{
$where = 'status=0 OR status=2';
$items = Pluf::factory('IDF_Queue')->getList(array('filter'=>$where,
'nb'=> 500));
Pluf_Log::event(array('IDF_Queue::process', $items->count()));
foreach ($items as $item) {
$item->status = 1;
$item->update();
}
foreach ($items as $item) {
$item->status = 1;
$item->processItem();
}
}
}