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.

scripts/queuectl.php

@@ -0,0 +1,85 @@
+#!/usr/bin/env php
+<?php
+/*
+ * StatusNet - the distributed open-source microblogging tool
+ * Copyright (C) 2010, StatusNet, Inc.
+ *
+ * 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/>.
+ */
+
+/**
+ * Sends control signals to running queue daemons.
+ *
+ * @author Brion Vibber <brion@status.net>
+ * @package QueueHandler
+ */
+
+define('INSTALLDIR', realpath(dirname(__FILE__) . '/..'));
+
+$shortoptions = 'ur';
+$longoptions = array('update', 'restart', 'stop');
+
+$helptext = <<<END_OF_QUEUECTL_HELP
+Send broadcast events to control any running queue handlers.
+(Currently for Stomp queues only.)
+
+Events relating to current site (as selected with -s etc)
+    -u --update       Announce new site or updated configuration. Running
+                      daemons will start subscribing to any new queues needed
+                      for this site.
+
+Global events:
+    -r --restart      Graceful restart of all threads
+       --stop         Graceful shutdown of all threads
+
+END_OF_QUEUECTL_HELP;
+
+require_once INSTALLDIR.'/scripts/commandline.inc';
+
+function doSendControl($message, $event, $param='')
+{
+    print $message;
+    $qm = QueueManager::get();
+    if ($qm->sendControlSignal($event, $param)) {
+        print " sent.\n";
+    } else {
+        print " FAILED.\n";
+    }
+}
+
+$actions = 0;
+
+if (have_option('u') || have_option('--update')) {
+    $nickname = common_config('site', 'nickname');
+    doSendControl("Sending site update signal to queue daemons for $nickname",
+                  "update", $nickname);
+    $actions++;
+}
+
+if (have_option('r') || have_option('--restart')) {
+    doSendControl("Sending graceful restart signal to queue daemons...",
+                  "restart");
+    $actions++;
+}
+
+if (have_option('--stop')) {
+    doSendControl("Sending graceful shutdown signal to queue daemons...",
+                  "shutdown");
+    $actions++;
+}
+
+if (!$actions) {
+    show_help();
+}
+