<?php /** * StatusNet, the distributed open-source microblogging tool * * Simple-minded queue manager for storing items in the database * * PHP version 5 * * LICENCE: This program is free software: you can redistribute it and/or modify * it under the terms of the GNU Affero General Public License as published by * the Free Software Foundation, either version 3 of the License, or * (at your option) any later version. * * This program 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 * GNU Affero General Public License for more details. * * You should have received a copy of the GNU Affero General Public License * along with this program. If not, see <http://www.gnu.org/licenses/>. * * @category QueueManager * @package StatusNet * @author Evan Prodromou <evan@status.net> * @copyright 2009 StatusNet, Inc. * @license http://www.fsf.org/licensing/licenses/agpl-3.0.html GNU Affero General Public License version 3.0 * @link http://status.net/ */ class DBQueueManager extends QueueManager { var $qis = array(); function enqueue($object, $queue) { $notice = $object; $qi = new Queue_item(); $qi->notice_id = $notice->id; $qi->transport = $queue; $qi->created = $notice->created; $result = $qi->insert(); if (!$result) { common_log_db_error($qi, 'INSERT', __FILE__); throw new ServerException('DB error inserting queue item'); } return true; } function service($queue, $handler) { while (true) { $this->_log(LOG_DEBUG, 'Checking for notices...'); $timeout = $handler->timeout(); $notice = $this->_nextItem($queue, $timeout); if (empty($notice)) { $this->_log(LOG_DEBUG, 'No notices waiting; idling.'); // Nothing in the queue. Do you // have other tasks, like servicing your // XMPP connection, to do? $handler->idle(QUEUE_HANDLER_MISS_IDLE); } else { $this->_log(LOG_INFO, 'Got notice '. $notice->id); // Yay! Got one! if ($handler->handle_notice($notice)) { $this->_log(LOG_INFO, 'Successfully handled notice '. $notice->id); $this->_done($notice, $queue); } else { $this->_log(LOG_INFO, 'Failed to handle notice '. $notice->id); $this->_fail($notice, $queue); } // Chance to e.g. service your XMPP connection $this->_log(LOG_DEBUG, 'Idling after success.'); $handler->idle(QUEUE_HANDLER_HIT_IDLE); } // XXX: when do we give up? } } function _nextItem($queue, $timeout=null) { $start = time(); $result = null; $sleeptime = 1; do { $qi = Queue_item::top($queue); if (empty($qi)) { $this->_log(LOG_DEBUG, "No new queue items, sleeping $sleeptime seconds."); sleep($sleeptime); $sleeptime *= 2; } else { $notice = Notice::staticGet('id', $qi->notice_id); if (!empty($notice)) { $result = $notice; } else { $this->_log(LOG_INFO, 'dequeued non-existent notice ' . $notice->id); $qi->delete(); $qi->free(); $qi = null; } $sleeptime = 1; } } while (empty($result) && (is_null($timeout) || (time() - $start) < $timeout)); return $result; } function _done($object, $queue) { // XXX: right now, we only handle notices $notice = $object; $qi = Queue_item::pkeyGet(array('notice_id' => $notice->id, 'transport' => $queue)); if (empty($qi)) { $this->_log(LOG_INFO, 'Cannot find queue item for notice '.$notice->id.', queue '.$queue); } else { if (empty($qi->claimed)) { $this->_log(LOG_WARNING, 'Reluctantly releasing unclaimed queue item '. 'for '.$notice->id.', queue '.$queue); } $qi->delete(); $qi->free(); $qi = null; } $this->_log(LOG_INFO, 'done with notice ID = ' . $notice->id); $notice->free(); $notice = null; } function _fail($object, $queue) { // XXX: right now, we only handle notices $notice = $object; $qi = Queue_item::pkeyGet(array('notice_id' => $notice->id, 'transport' => $queue)); if (empty($qi)) { $this->_log(LOG_INFO, 'Cannot find queue item for notice '.$notice->id.', queue '.$queue); } else { if (empty($qi->claimed)) { $this->_log(LOG_WARNING, 'Ignoring failure for unclaimed queue item '. 'for '.$notice->id.', queue '.$queue); } else { $orig = clone($qi); $qi->claimed = null; $qi->update($orig); $qi = null; } } $this->_log(LOG_INFO, 'done with notice ID = ' . $notice->id); $notice->free(); $notice = null; } function _log($level, $msg) { common_log($level, 'DBQueueManager: '.$msg); } }