Major refactoring of queue handlers to support running multiple sites in one daemon.

Key changes:
* Initialization code moved from common.php to StatusNet class;
  can now switch configurations during runtime.
* As a consequence, configuration files must now be idempotent...
  Be careful with constant, function or class definitions.
* Control structure for daemons/QueueManager/QueueHandler has been refactored;
  the run loop is now managed by IoMaster run via scripts/queuedaemon.php
  IoManager subclasses are woken to handle socket input or polling, and may
  cover multiple sites.
* Plugins can implement notice queue handlers more easily by registering a
  QueueHandler class; no more need to add a daemon.

The new QueueDaemon runs from scripts/queuedaemon.php:

* This replaces most of the old *handler.php scripts; they've been refactored
  to the bare handler classes.
* Spawns multiple child processes to spread load; defaults to CPU count on
  Linux and Mac OS X systems, or override with --threads=N
* When multithreaded, child processes are automatically respawned on failure.
* Threads gracefully shut down and restart when passing a soft memory limit
  (defaults to 90% of memory_limit), limiting damage from memory leaks.
* Support for UDP-based monitoring: http://www.gitorious.org/snqmon

Rough control flow diagram:
QueueDaemon -> IoMaster -> IoManager
                           QueueManager [listen or poll] -> QueueHandler
                           XmppManager [ping & keepalive]
                           XmppConfirmManager [poll updates]

Todo:

* Respawning features not currently available running single-threaded.
* When running single-site, configuration changes aren't picked up.
* New sites or config changes affecting queue subscriptions are not yet
  handled without a daemon restart.
* SNMP monitoring output to integrate with general tools (nagios, ganglia)
* Convert XMPP confirmation message sends to use stomp queue instead of polling
* Convert xmppdaemon.php to IoManager?
* Convert Twitter status, friends import polling daemons to IoManager
* Clean up some error reporting and failure modes
* May need to adjust queue priorities for best perf in backlog/flood cases

Detailed code history available in my daemon-work branch:
http://www.gitorious.org/~brion/statusnet/brion-fixes/commits/daemon-work

1 files changed, 116 insertions, 0 deletions

diff --git a/lib/queuemonitor.php b/lib/queuemonitor.php
new file mode 100644
index 000000000..1c306a629
--- /dev/null
+++ b/lib/queuemonitor.php
@@ -0,0 +1,116 @@
+<?php
+/**
+ * StatusNet, the distributed open-source microblogging tool
+ *
+ * Monitoring output helper for IoMaster and IoManager/QueueManager
+ *
+ * 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    Brion Vibber <brion@status.net>
+ * @copyright 2010 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 QueueMonitor
+{
+    protected $monSocket = null;
+
+    /**
+     * Increment monitoring statistics for a given counter, if configured.
+     * Only explicitly listed thread/site/queue owners will be incremented.
+     *
+     * @param string $key counter name
+     * @param array $owners list of owner keys like 'queue:jabber' or 'site:stat01'
+     */
+    public function stats($key, $owners=array())
+    {
+        $this->ping(array('counter' => $key,
+                          'owners' => $owners));
+    }
+
+    /**
+     * Send thread state update to the monitoring server, if configured.
+     *
+     * @param string $thread ID (eg 'generic.1')
+     * @param string $state ('init', 'queue', 'shutdown' etc)
+     * @param string $substate (optional, eg queue name 'omb' 'sms' etc)
+     */
+    public function logState($threadId, $state, $substate='')
+    {
+        $this->ping(array('thread_id' => $threadId,
+                          'state' => $state,
+                          'substate' => $substate,
+                          'ts' => microtime(true)));
+    }
+
+    /**
+     * General call to the monitoring server
+     */
+    protected function ping($data)
+    {
+        $target = common_config('queue', 'monitor');
+        if (empty($target)) {
+            return;
+        }
+
+        $data = $this->prepMonitorData($data);
+
+        if (substr($target, 0, 4) == 'udp:') {
+            $this->pingUdp($target, $data);
+        } else if (substr($target, 0, 5) == 'http:') {
+            $this->pingHttp($target, $data);
+        } else {
+            common_log(LOG_ERR, __METHOD__ . ' unknown monitor target type ' . $target);
+        }
+    }
+
+    protected function pingUdp($target, $data)
+    {
+        if (!$this->monSocket) {
+            $this->monSocket = stream_socket_client($target, $errno, $errstr);
+        }
+        if ($this->monSocket) {
+            $post = http_build_query($data, '', '&');
+            stream_socket_sendto($this->monSocket, $post);
+        } else {
+            common_log(LOG_ERR, __METHOD__ . " UDP logging fail: $errstr");
+        }
+    }
+
+    protected function pingHttp($target, $data)
+    {
+        $client = new HTTPClient();
+        $result = $client->post($target, array(), $data);
+        
+        if (!$result->isOk()) {
+            common_log(LOG_ERR, __METHOD__ . ' HTTP ' . $result->getStatus() .
+                                ': ' . $result->getBody());
+        }
+    }
+
+    protected function prepMonitorData($data)
+    {
+        #asort($data);
+        #$macdata = http_build_query($data, '', '&');
+        #$key = 'This is a nice old key';
+        #$data['hmac'] = hash_hmac('sha256', $macdata, $key);
+        return $data;
+    }
+
+}