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, 7 insertions, 39 deletions

diff --git a/plugins/Facebook/FacebookPlugin.php b/plugins/Facebook/FacebookPlugin.php
index de91bf24a..4266b886d 100644
--- a/plugins/Facebook/FacebookPlugin.php
+++ b/plugins/Facebook/FacebookPlugin.php
@@ -114,6 +114,9 @@ class FacebookPlugin extends Plugin
         case 'FBCSettingsNav':
             include_once INSTALLDIR . '/plugins/Facebook/FBCSettingsNav.php';
             return false;
+        case 'FacebookQueueHandler':
+            include_once INSTALLDIR . '/plugins/Facebook/facebookqueuehandler.php';
+            return false;
         default:
             return true;
         }
@@ -508,50 +511,15 @@ class FacebookPlugin extends Plugin
     }
 
     /**
-     * broadcast the message when not using queuehandler
+     * Register Facebook notice queue handler
      *
-     * @param Notice &$notice the notice
-     * @param array  $queue   destination queue
+     * @param QueueManager $manager
      *
      * @return boolean hook return
      */
-
-    function onUnqueueHandleNotice(&$notice, $queue)
-    {
-        if (($queue == 'facebook') && ($this->_isLocal($notice))) {
-            facebookBroadcastNotice($notice);
-            return false;
-        }
-        return true;
-    }
-
-    /**
-     * Determine whether the notice was locally created
-     *
-     * @param Notice $notice the notice
-     *
-     * @return boolean locality
-     */
-
-    function _isLocal($notice)
-    {
-        return ($notice->is_local == Notice::LOCAL_PUBLIC ||
-                $notice->is_local == Notice::LOCAL_NONPUBLIC);
-    }
-
-    /**
-     * Add Facebook queuehandler to the list of daemons to start
-     *
-     * @param array $daemons the list fo daemons to run
-     *
-     * @return boolean hook return
-     *
-     */
-
-    function onGetValidDaemons($daemons)
+    function onEndInitializeQueueManager($manager)
     {
-        array_push($daemons, INSTALLDIR .
-                   '/plugins/Facebook/facebookqueuehandler.php');
+        $manager->connect('facebook', 'FacebookQueueHandler');
         return true;
     }