summaryrefslogtreecommitdiff
path: root/lib/dbqueuemanager.php
blob: a37a8ffdf645c2699a2bee671b4a1f45abf3104b (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
<?php
/**
 * Laconica, 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   Laconica
 * @author    Evan Prodromou <evan@controlyourself.ca>
 * @author    Sarven Capadisli <csarven@controlyourself.ca>
 * @copyright 2009 Control Yourself, Inc.
 * @license   http://www.fsf.org/licensing/licenses/agpl-3.0.html GNU Affero General Public License version 3.0
 * @link      http://laconi.ca/
 */

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;

        do {
            $qi = Queue_item::top($queue);
            if (!empty($qi)) {
                $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();
                    $qi = null;
                }
            }
        } while (empty($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);
    }
}