<?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 $control;
protected $sites = array();
protected $subscriptions = array();
protected $useTransactions = true;
protected $transaction = null;
protected $transactionCount = 0;
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');
$this->control = common_config('queue', 'control_channel');
}
/**
* Tell the i/o master we only need a single instance to cover
* all sites running in this process.
*/
public static function multiSite()
{
return IoManager::INSTANCE_PER_PROCESS;
}
/**
* Record each site we'll be handling input for in this process,
* so we can listen to the necessary queues for it.
*
* @fixme possibly actually do subscription here to save another
* loop over all sites later?
* @fixme possibly don't assume it's the current site
*/
public function addSite($server)
{
$this->sites[] = $server;
$this->initialize();
}
/**
* 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.
*
* Currently only relevant for multi-site queue managers such as Stomp.
*
* @param string $event event key
* @param string $param optional parameter to append to key
* @return boolean success
*/
public function sendControlSignal($event, $param='')
{
$message = $event;
if ($param != '') {
$message .= ':' . $param;
}
$this->_connect();
$result = $this->con->send($this->control,
$message,
array ('created' => common_sql_now()));
if ($result) {
$this->_log(LOG_INFO, "Sent control ping to queue daemons: $message");
return true;
} else {
$this->_log(LOG_ERR, "Failed sending control ping to queue daemons: $message");
return false;
}
}
/**
* Instantiate the appropriate QueueHandler class for the given queue.
*
* @param string $queue
* @return mixed QueueHandler or null
*/
function getHandler($queue)
{
$handlers = $this->handlers[$this->currentSite()];
if (isset($handlers[$queue])) {
$class = $handlers[$queue];
if (class_exists($class)) {
return new $class();
} else {
common_log(LOG_ERR, "Nonexistent handler class '$class' for queue '$queue'");
}
} else {
common_log(LOG_ERR, "Requested handler for unkown queue '$queue'");
}
return null;
}
/**
* Get a list of all registered queue transport names.
*
* @return array of strings
*/
function getQueues()
{
$group = $this->activeGroup();
$site = $this->currentSite();
if (empty($this->groups[$site][$group])) {
return array();
} else {
return array_keys($this->groups[$site][$group]);
}
}
/**
* Register a queue transport name and handler class for your plugin.
* Only registered transports will be reliably picked up!
*
* @param string $transport
* @param string $class
* @param string $group
*/
public function connect($transport, $class, $group='queuedaemon')
{
$this->handlers[$this->currentSite()][$transport] = $class;
$this->groups[$this->currentSite()][$group][$transport] = $class;
}
/**
* Saves a notice object reference into the queue item table.
* @return boolean true on success
*/
public function enqueue($object, $queue)
{
$msg = $this->encode($object);
$rep = $this->logrep($object);
$this->_connect();
// XXX: serialize and send entire notice
$result = $this->con->send($this->queueName($queue),
$msg, // BODY of the message
array ('created' => common_sql_now(),
'persistent' => 'true'));
if (!$result) {
common_log(LOG_ERR, "Error sending $rep to $queue queue");
return false;
}
common_log(LOG_DEBUG, "complete remote queueing $rep 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) {
$dest = $frame->headers['destination'];
if ($dest == $this->control) {
if (!$this->handleControlSignal($frame)) {
// We got a control event that requests a shutdown;
// close out and stop handling anything else!
break;
}
} else {
$ok = $ok && $this->handleItem($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);
$this->_connect();
common_log(LOG_INFO, "Subscribing to $this->control");
$this->con->subscribe($this->control);
if ($this->sites) {
foreach ($this->sites as $server) {
StatusNet::init($server);
$this->doSubscribe();
}
} else {
$this->doSubscribe();
}
$this->begin();
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 there are any outstanding delivered messages we haven't processed,
// free them for another thread to take.
$this->rollback();
$this->con->unsubscribe($this->control);
if ($this->sites) {
foreach ($this->sites as $server) {
StatusNet::init($server);
$this->doUnsubscribe();
}
} else {
$this->doUnsubscribe();
}
return true;
}
/**
* Get identifier of the currently active site configuration
* @return string
*/
protected function currentSite()
{
return common_config('site', 'server'); // @fixme switch to nickname
}
/**
* Lazy open connection to Stomp queue server.
*/
protected function _connect()
{
if (empty($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()
{
$site = $this->currentSite();
$this->_connect();
foreach ($this->getQueues() as $queue) {
$rawqueue = $this->queueName($queue);
$this->subscriptions[$site][$queue] = $rawqueue;
$this->_log(LOG_INFO, "Subscribing to $rawqueue");
$this->con->subscribe($rawqueue);
}
}
/**
* Subscribe from all enabled notice queues for the current site.
*/
protected function doUnsubscribe()
{
$site = $this->currentSite();
$this->_connect();
if (!empty($this->subscriptions[$site])) {
foreach ($this->subscriptions[$site] as $queue => $rawqueue) {
$this->_log(LOG_INFO, "Unsubscribing from $rawqueue");
$this->con->unsubscribe($rawqueue);
unset($this->subscriptions[$site][$queue]);
}
}
}
/**
* Handle and acknowledge an 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 $frame
* @return bool
*/
protected function handleItem($frame)
{
list($site, $queue) = $this->parseDestination($frame->headers['destination']);
if ($site != $this->currentSite()) {
$this->stats('switch');
StatusNet::init($site);
}
if (is_numeric($frame->body)) {
$id = intval($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");
$this->ack($frame);
$this->commit();
$this->begin();
$this->stats('badnotice', $queue);
return false;
}
$item = $notice;
} else {
// @fixme should we serialize, or json, or what here?
$info = "string posted at {$frame->headers['created']} in queue $queue";
$item = $frame->body;
}
$handler = $this->getHandler($queue);
if (!$handler) {
$this->_log(LOG_ERR, "Missing handler class; skipping $info");
$this->ack($frame);
$this->commit();
$this->begin();
$this->stats('badhandler', $queue);
return false;
}
$ok = $handler->handle($item);
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...
$this->ack($frame);
$this->enqueue($item, $queue);
$this->commit();
$this->begin();
$this->stats('requeued', $queue);
return false;
}
$this->_log(LOG_INFO, "Successfully handled $info");
$this->ack($frame);
$this->commit();
$this->begin();
$this->stats('handled', $queue);
return true;
}
/**
* Process a control signal broadcast.
*
* @param array $frame Stomp frame
* @return bool true to continue; false to stop further processing.
*/
protected function handleControlSignal($frame)
{
$message = trim($frame->body);
if (strpos($message, ':') !== false) {
list($event, $param) = explode(':', $message, 2);
} else {
$event = $message;
$param = '';
}
$shutdown = false;
if ($event == 'shutdown') {
$this->master->requestShutdown();
$shutdown = true;
} else if ($event == 'restart') {
$this->master->requestRestart();
$shutdown = true;
} else if ($event == 'update') {
$this->updateSiteConfig($param);
} else {
$this->_log(LOG_ERR, "Ignoring unrecognized control message: $message");
}
$this->ack($frame);
$this->commit();
$this->begin();
return $shutdown;
}
/**
* Set us up with queue subscriptions for a new site added at runtime,
* triggered by a broadcast to the 'statusnet-control' topic.
*
* @param array $frame Stomp frame
* @return bool true to continue; false to stop further processing.
*/
protected function updateSiteConfig($nickname)
{
if (empty($this->sites)) {
if ($nickname == common_config('site', 'nickname')) {
StatusNet::init(common_config('site', 'server'));
$this->doUnsubscribe();
$this->doSubscribe();
} else {
$this->_log(LOG_INFO, "Ignoring update ping for other site $nickname");
}
} else {
$sn = Status_network::staticGet($nickname);
if ($sn) {
$server = $sn->getServerName(); // @fixme do config-by-nick
StatusNet::init($server);
if (empty($this->sites[$server])) {
$this->addSite($server);
}
$this->_log(LOG_INFO, "(Re)subscribing to queues for site $nickname / $server");
$this->doUnsubscribe();
$this->doSubscribe();
$this->stats('siteupdate');
} else {
$this->_log(LOG_ERR, "Ignoring ping for unrecognized new site $nickname");
}
}
}
/**
* 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') .
$this->currentSite() . '/' . $queue;
}
/**
* Returns the site and queue name from the server-side queue.
*
* @param string queue destination (eg '/queue/statusnet/identi.ca/sms')
* @return array of site and queue: ('identi.ca','sms') or false if unrecognized
*/
protected function parseDestination($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: '.$msg);
}
protected function begin()
{
if ($this->useTransactions) {
if ($this->transaction) {
throw new Exception("Tried to start transaction in the middle of a transaction");
}
$this->transactionCount++;
$this->transaction = $this->master->id . '-' . $this->transactionCount . '-' . time();
$this->con->begin($this->transaction);
}
}
protected function ack($frame)
{
if ($this->useTransactions) {
if (!$this->transaction) {
throw new Exception("Tried to ack but not in a transaction");
}
}
$this->con->ack($frame, $this->transaction);
}
protected function commit()
{
if ($this->useTransactions) {
if (!$this->transaction) {
throw new Exception("Tried to commit but not in a transaction");
}
$this->con->commit($this->transaction);
$this->transaction = null;
}
}
protected function rollback()
{
if ($this->useTransactions) {
if (!$this->transaction) {
throw new Exception("Tried to rollback but not in a transaction");
}
$this->con->commit($this->transaction);
$this->transaction = null;
}
}
}