gnu-social/lib/stompqueuemanager.php
Brion Vibber ec145b73fc 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
2010-01-12 20:45:09 -08:00

312 lines
9.2 KiB
PHP

<?php
/**
* StatusNet, the distributed open-source microblogging tool
*
* Abstract class for queue managers
*
* PHP version 5
*
* LICENCE: 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/>.
*
* @category QueueManager
* @package StatusNet
* @author Evan Prodromou <evan@status.net>
* @author Sarven Capadisli <csarven@status.net>
* @copyright 2009 StatusNet, Inc.
* @license http://www.fsf.org/licensing/licenses/agpl-3.0.html GNU Affero General Public License version 3.0
* @link http://status.net/
*/
require_once 'Stomp.php';
class StompQueueManager extends QueueManager
{
var $server = null;
var $username = null;
var $password = null;
var $base = null;
var $con = null;
protected $master = null;
protected $sites = array();
function __construct()
{
parent::__construct();
$this->server = common_config('queue', 'stomp_server');
$this->username = common_config('queue', 'stomp_username');
$this->password = common_config('queue', 'stomp_password');
$this->base = common_config('queue', 'queue_basename');
}
/**
* Tell the i/o master we only need a single instance to cover
* all sites running in this process.
*/
public static function multiSite()
{
return IoManager::INSTANCE_PER_PROCESS;
}
/**
* Record each site we'll be handling input for in this process,
* so we can listen to the necessary queues for it.
*
* @fixme possibly actually do subscription here to save another
* loop over all sites later?
*/
public function addSite($server)
{
$this->sites[] = $server;
}
/**
* Saves a notice object reference into the queue item table.
* @return boolean true on success
*/
public function enqueue($object, $queue)
{
$notice = $object;
$this->_connect();
// XXX: serialize and send entire notice
$result = $this->con->send($this->queueName($queue),
$notice->id, // BODY of the message
array ('created' => $notice->created));
if (!$result) {
common_log(LOG_ERR, 'Error sending to '.$queue.' queue');
return false;
}
common_log(LOG_DEBUG, 'complete remote queueing notice ID = '
. $notice->id . ' for ' . $queue);
$this->stats('enqueued', $queue);
}
/**
* Send any sockets we're listening on to the IO manager
* to wait for input.
*
* @return array of resources
*/
public function getSockets()
{
return array($this->con->getSocket());
}
/**
* We've got input to handle on our socket!
* Read any waiting Stomp frame(s) and process them.
*
* @param resource $socket
* @return boolean ok on success
*/
public function handleInput($socket)
{
assert($socket === $this->con->getSocket());
$ok = true;
$frames = $this->con->readFrames();
foreach ($frames as $frame) {
$ok = $ok && $this->_handleNotice($frame);
}
return $ok;
}
/**
* Initialize our connection and subscribe to all the queues
* we're going to need to handle...
*
* Side effects: in multi-site mode, may reset site configuration.
*
* @param IoMaster $master process/event controller
* @return bool return false on failure
*/
public function start($master)
{
parent::start($master);
if ($this->sites) {
foreach ($this->sites as $server) {
StatusNet::init($server);
$this->doSubscribe();
}
} else {
$this->doSubscribe();
}
return true;
}
/**
* Subscribe to all the queues we're going to need to handle...
*
* Side effects: in multi-site mode, may reset site configuration.
*
* @return bool return false on failure
*/
public function finish()
{
if ($this->sites) {
foreach ($this->sites as $server) {
StatusNet::init($server);
$this->doUnsubscribe();
}
} else {
$this->doUnsubscribe();
}
return true;
}
/**
* Lazy open connection to Stomp queue server.
*/
protected function _connect()
{
if (empty($this->con)) {
$this->_log(LOG_INFO, "Connecting to '$this->server' as '$this->username'...");
$this->con = new LiberalStomp($this->server);
if ($this->con->connect($this->username, $this->password)) {
$this->_log(LOG_INFO, "Connected.");
} else {
$this->_log(LOG_ERR, 'Failed to connect to queue server');
throw new ServerException('Failed to connect to queue server');
}
}
}
/**
* Subscribe to all enabled notice queues for the current site.
*/
protected function doSubscribe()
{
$this->_connect();
foreach ($this->getQueues() as $queue) {
$rawqueue = $this->queueName($queue);
$this->_log(LOG_INFO, "Subscribing to $rawqueue");
$this->con->subscribe($rawqueue);
}
}
/**
* Subscribe from all enabled notice queues for the current site.
*/
protected function doUnsubscribe()
{
$this->_connect();
foreach ($this->getQueues() as $queue) {
$this->con->unsubscribe($this->queueName($queue));
}
}
/**
* Handle and acknowledge a notice event that's come in through a queue.
*
* If the queue handler reports failure, the message is requeued for later.
* Missing notices or handler classes will drop the message.
*
* Side effects: in multi-site mode, may reset site configuration to
* match the site that queued the event.
*
* @param StompFrame $frame
* @return bool
*/
protected function _handleNotice($frame)
{
list($site, $queue) = $this->parseDestination($frame->headers['destination']);
if ($site != common_config('site', 'server')) {
$this->stats('switch');
StatusNet::init($site);
}
$id = intval($frame->body);
$info = "notice $id posted at {$frame->headers['created']} in queue $queue";
$notice = Notice::staticGet('id', $id);
if (empty($notice)) {
$this->_log(LOG_WARNING, "Skipping missing $info");
$this->con->ack($frame);
$this->stats('badnotice', $queue);
return false;
}
$handler = $this->getHandler($queue);
if (!$handler) {
$this->_log(LOG_ERROR, "Missing handler class; skipping $info");
$this->con->ack($frame);
$this->stats('badhandler', $queue);
return false;
}
$ok = $handler->handle_notice($notice);
if (!$ok) {
$this->_log(LOG_WARNING, "Failed handling $info");
// FIXME we probably shouldn't have to do
// this kind of queue management ourselves;
// if we don't ack, it should resend...
$this->con->ack($frame);
$this->enqueue($notice, $queue);
$this->stats('requeued', $queue);
return false;
}
$this->_log(LOG_INFO, "Successfully handled $info");
$this->con->ack($frame);
$this->stats('handled', $queue);
return true;
}
/**
* Combines the queue_basename from configuration with the
* site server name and queue name to give eg:
*
* /queue/statusnet/identi.ca/sms
*
* @param string $queue
* @return string
*/
protected function queueName($queue)
{
return common_config('queue', 'queue_basename') .
common_config('site', 'server') . '/' . $queue;
}
/**
* Returns the site and queue name from the server-side queue.
*
* @param string queue destination (eg '/queue/statusnet/identi.ca/sms')
* @return array of site and queue: ('identi.ca','sms') or false if unrecognized
*/
protected function parseDestination($dest)
{
$prefix = common_config('queue', 'queue_basename');
if (substr($dest, 0, strlen($prefix)) == $prefix) {
$rest = substr($dest, strlen($prefix));
return explode("/", $rest, 2);
} else {
common_log(LOG_ERR, "Got a message from unrecognized stomp queue: $dest");
return array(false, false);
}
}
function _log($level, $msg)
{
common_log($level, 'StompQueueManager: '.$msg);
}
}