XMPP queued output & initial retooling of DB queue manager to support non-Notice objects.

Queue handlers for XMPP individual & firehose output now send their XML stanzas
to another output queue instead of connecting directly to the chat server. This
lets us have as many general processing threads as we need, while all actual
XMPP input and output go through a single daemon with a single connection open.

This avoids problems with multiple connected resources:
* multiple windows shown in some chat clients (psi, gajim, kopete)
* extra load on server
* incoming message delivery forwarding issues

Database changes:
* queue_item drops 'notice_id' in favor of a 'frame' blob.
  This is based on Craig Andrews' work branch to generalize queues to take any
  object, but conservatively leaving out the serialization for now.
  Table updater (preserves any existing queued items) in db/rc3to09.sql

Code changes to watch out for:
* Queue handlers should now define a handle() method instead of handle_notice()
* QueueDaemon and XmppDaemon now share common i/o (IoMaster) and respawning
  thread management (RespawningDaemon) infrastructure.
* The polling XmppConfirmManager has been dropped, as the message is queued
  directly when saving IM settings.
* Enable $config['queue']['debug_memory'] to output current memory usage at
  each run through the event loop to watch for memory leaks

To do:
* Adapt XMPP i/o to component connection mode for multi-site support.
* XMPP input can also be broken out to a queue, which would allow the actual
  notice save etc to be handled by general queue threads.
* Make sure there are no problems with simply pushing serialized Notice objects
  to queues.
* Find a way to improve interactive performance of the database-backed queue
  handler; polling is pretty painful to XMPP.
* Possibly redo the way QueueHandlers are injected into a QueueManager. The
  grouping used to split out the XMPP output queue is a bit awkward.

1 files changed, 26 insertions, 123 deletions

diff --git a/scripts/queuedaemon.php b/scripts/queuedaemon.php
index 162f617e0..a9cfda6d7 100755
--- a/scripts/queuedaemon.php
+++ b/scripts/queuedaemon.php
@@ -29,6 +29,8 @@ $longoptions = array('id=', 'foreground', 'all', 'threads=', 'skip-xmpp', 'xmpp-
  *
  * Recognizes Linux and Mac OS X; others will return default of 1.
  *
+ * @fixme move this to SpawningDaemon, but to get the default val for help
+ *        text we seem to need it before loading infrastructure
  * @return intval
  */
 function getProcessorCount()
@@ -83,143 +85,29 @@ define('CLAIM_TIMEOUT', 1200);
  * We can then pass individual items through the QueueHandler subclasses
  * they belong to.
  */
-class QueueDaemon extends Daemon
+class QueueDaemon extends SpawningDaemon
 {
-    protected $allsites;
-    protected $threads=1;
+    protected $allsites = false;
 
     function __construct($id=null, $daemonize=true, $threads=1, $allsites=false)
     {
-        parent::__construct($daemonize);
-
-        if ($id) {
-            $this->set_id($id);
-        }
+        parent::__construct($id, $daemonize, $threads);
         $this->all = $allsites;
-        $this->threads = $threads;
-    }
-
-    /**
-     * How many seconds a polling-based queue manager should wait between
-     * checks for new items to handle.
-     *
-     * Defaults to 60 seconds; override to speed up or slow down.
-     *
-     * @return int timeout in seconds
-     */
-    function timeout()
-    {
-        return 60;
-    }
-
-    function name()
-    {
-        return strtolower(get_class($this).'.'.$this->get_id());
-    }
-
-    function run()
-    {
-        if ($this->threads > 1) {
-            return $this->runThreads();
-        } else {
-            return $this->runLoop();
-        }
-    }
-    
-    function runThreads()
-    {
-        $children = array();
-        for ($i = 1; $i <= $this->threads; $i++) {
-            $pid = pcntl_fork();
-            if ($pid < 0) {
-                print "Couldn't fork for thread $i; aborting\n";
-                exit(1);
-            } else if ($pid == 0) {
-                $this->runChild($i);
-                exit(0);
-            } else {
-                $this->log(LOG_INFO, "Spawned thread $i as pid $pid");
-                $children[$i] = $pid;
-            }
-        }
-        
-        $this->log(LOG_INFO, "Waiting for children to complete.");
-        while (count($children) > 0) {
-            $status = null;
-            $pid = pcntl_wait($status);
-            if ($pid > 0) {
-                $i = array_search($pid, $children);
-                if ($i === false) {
-                    $this->log(LOG_ERR, "Unrecognized child pid $pid exited!");
-                    continue;
-                }
-                unset($children[$i]);
-                $this->log(LOG_INFO, "Thread $i pid $pid exited.");
-                
-                $pid = pcntl_fork();
-                if ($pid < 0) {
-                    print "Couldn't fork to respawn thread $i; aborting thread.\n";
-                } else if ($pid == 0) {
-                    $this->runChild($i);
-                    exit(0);
-                } else {
-                    $this->log(LOG_INFO, "Respawned thread $i as pid $pid");
-                    $children[$i] = $pid;
-                }
-            }
-        }
-        $this->log(LOG_INFO, "All child processes complete.");
-        return true;
-    }
-
-    function runChild($thread)
-    {
-        $this->set_id($this->get_id() . "." . $thread);
-        $this->resetDb();
-        $this->runLoop();
-    }
-
-    /**
-     * Reconnect to the database for each child process,
-     * or they'll get very confused trying to use the
-     * same socket.
-     */
-    function resetDb()
-    {
-        // @fixme do we need to explicitly open the db too
-        // or is this implied?
-        global $_DB_DATAOBJECT;
-        unset($_DB_DATAOBJECT['CONNECTIONS']);
-
-        // Reconnect main memcached, or threads will stomp on
-        // each other and corrupt their requests.
-        $cache = common_memcache();
-        if ($cache) {
-            $cache->reconnect();
-        }
-
-        // Also reconnect memcached for status_network table.
-        if (!empty(Status_network::$cache)) {
-            Status_network::$cache->close();
-            Status_network::$cache = null;
-        }
     }
 
     /**
      * Setup and start of run loop for this queue handler as a daemon.
      * Most of the heavy lifting is passed on to the QueueManager's service()
-     * method, which passes control on to the QueueHandler's handle_notice()
-     * method for each notice that comes in on the queue.
-     *
-     * Most of the time this won't need to be overridden in a subclass.
+     * method, which passes control on to the QueueHandler's handle()
+     * method for each item that comes in on the queue.
      *
      * @return boolean true on success, false on failure
      */
-    function runLoop()
+    function runThread()
     {
         $this->log(LOG_INFO, 'checking for queued notices');
 
-        $master = new IoMaster($this->get_id());
+        $master = new QueueMaster($this->get_id());
         $master->init($this->all);
         $master->service();
 
@@ -229,10 +117,25 @@ class QueueDaemon extends Daemon
 
         return true;
     }
+}
 
-    function log($level, $msg)
+class QueueMaster extends IoMaster
+{
+    /**
+     * Initialize IoManagers for the currently configured site
+     * which are appropriate to this instance.
+     */
+    function initManagers()
     {
-        common_log($level, get_class($this) . ' ('. $this->get_id() .'): '.$msg);
+        $classes = array();
+        if (Event::handle('StartQueueDaemonIoManagers', array(&$classes))) {
+            $classes[] = 'QueueManager';
+        }
+        Event::handle('EndQueueDaemonIoManagers', array(&$classes));
+
+        foreach ($classes as $class) {
+            $this->instantiate($class);
+        }
     }
 }