Control channel for queue daemons to request graceful shutdown, restart, or update to listen to a newly added or reconfigured site.

  queuectl.php --update -s<site>
  queuectl.php --stop
  queuectl.php --restart

Default control channel is /topic/statusnet-control. For external utilities to send a site update ping direct to the queue server, connect via Stomp and send a message formatted thus:

  update:<nickname>

(Nickname here, *not* server hostname! The rest of the queues will be updated to use nicknames later.)

Note that all currently-connected queue daemons will get these notifications, including both queuedaemon.php and xmppdaemon.php. (XMPP will ignore site update requests for sites that it's not handling.)

Limitations:
* only implemented for stomp queue manager so far
* --update may not yet handle a changed server name properly
* --restart won't reload PHP code files that were already loaded at startup. Still need to stop and restart the daemons from 'outside' when updating code base.

1 files changed, 17 insertions, 0 deletions

diff --git a/lib/queuemanager.php b/lib/queuemanager.php
index 1bc8de1f7..afe710e88 100644
--- a/lib/queuemanager.php
+++ b/lib/queuemanager.php
@@ -101,6 +101,23 @@ abstract class QueueManager extends IoManager
     }
 
     /**
+     * Optional; ping any running queue handler daemons with a notification
+     * such as announcing a new site to handle or requesting clean shutdown.
+     * This avoids having to restart all the daemons manually to update configs
+     * and such.
+     *
+     * Called from scripts/queuectl.php controller utility.
+     *
+     * @param string $event event key
+     * @param string $param optional parameter to append to key
+     * @return boolean success
+     */
+    public function sendControlSignal($event, $param='')
+    {
+        throw new Exception(get_class($this) . " does not support control signals.");
+    }
+
+    /**
      * Store an object (usually/always a Notice) into the given queue
      * for later processing. No guarantee is made on when it will be
      * processed; it could be immediately or at some unspecified point