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, 10 insertions, 85 deletions

diff --git a/lib/queuehandler.php b/lib/queuehandler.php
index 613be6e33..2909cd83b 100644
--- a/lib/queuehandler.php
+++ b/lib/queuehandler.php
@@ -22,51 +22,20 @@ if (!defined('STATUSNET') && !defined('LACONICA')) { exit(1); }
 /**
  * Base class for queue handlers.
  *
- * As extensions of the Daemon class, each queue handler has the ability
- * to launch itself in the background, at which point it'll pass control
- * to the configured QueueManager class to poll for updates.
+ * As of 0.9, queue handlers are short-lived for items as they are
+ * dequeued by a QueueManager running in an IoMaster in a daemon
+ * such as queuedaemon.php.
+ *
+ * Extensions requiring long-running maintenance or polling should
+ * register an IoManager.
  *
  * Subclasses must override at least the following methods:
  * - transport
- * - handle_notice
+ * - handle
  */
-#class QueueHandler extends Daemon
 class QueueHandler
 {
 
-#    function __construct($id=null, $daemonize=true)
-#    {
-#        parent::__construct($daemonize);
-#
-#        if ($id) {
-#            $this->set_id($id);
-#        }
-#    }
-
-    /**
-     * 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.
-     *
-     * @fixme not really compatible with global queue manager
-     * @return int timeout in seconds
-     */
-#    function timeout()
-#    {
-#        return 60;
-#    }
-
-#    function class_name()
-#    {
-#        return ucfirst($this->transport()) . 'Handler';
-#    }
-
-#    function name()
-#    {
-#        return strtolower($this->class_name().'.'.$this->get_id());
-#    }
-
     /**
      * Return transport keyword which identifies items this queue handler
      * services; must be defined for all subclasses.
@@ -83,61 +52,17 @@ class QueueHandler
 
     /**
      * Here's the meat of your queue handler -- you're handed a Notice
-     * object, which you may do as you will with.
+     * or other object, which you may do as you will with.
      *
      * If this function indicates failure, a warning will be logged
      * and the item is placed back in the queue to be re-run.
      *
-     * @param Notice $notice
-     * @return boolean true on success, false on failure
-     */
-    function handle_notice($notice)
-    {
-        return true;
-    }
-
-    /**
-     * 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 back to our 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.
-     *
+     * @param mixed $object
      * @return boolean true on success, false on failure
      */
-    function run()
+    function handle($object)
     {
-        if (!$this->start()) {
-            $this->log(LOG_WARNING, 'failed to start');
-            return false;
-        }
-
-        $this->log(LOG_INFO, 'checking for queued notices');
-
-        $queue   = $this->transport();
-        $timeout = $this->timeout();
-
-        $qm = QueueManager::get();
-
-        $qm->service($queue, $this);
-
-        $this->log(LOG_INFO, 'finished servicing the queue');
-
-        if (!$this->finish()) {
-            $this->log(LOG_WARNING, 'failed to clean up');
-            return false;
-        }
-
-        $this->log(LOG_INFO, 'terminating normally');
-
         return true;
     }
-
-
-    function log($level, $msg)
-    {
-        common_log($level, $this->class_name() . ' ('. $this->get_id() .'): '.$msg);
-    }
 }