gnu-social/lib/iomaster.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

362 lines
11 KiB
PHP

<?php
/**
* StatusNet, the distributed open-source microblogging tool
*
* I/O manager to wrap around socket-reading and polling queue & connection 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 Brion Vibber <brion@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/
*/
class IoMaster
{
public $id;
protected $multiSite = false;
protected $managers = array();
protected $singletons = array();
protected $pollTimeouts = array();
protected $lastPoll = array();
/**
* @param string $id process ID to use in logging/monitoring
*/
public function __construct($id)
{
$this->id = $id;
$this->monitor = new QueueMonitor();
}
public function init($multiSite=null)
{
if ($multiSite !== null) {
$this->multiSite = $multiSite;
}
if ($this->multiSite) {
$this->sites = $this->findAllSites();
} else {
$this->sites = array(common_config('site', 'server'));
}
if (empty($this->sites)) {
throw new Exception("Empty status_network table, cannot init");
}
foreach ($this->sites as $site) {
if ($site != common_config('site', 'server')) {
StatusNet::init($site);
}
$classes = array();
if (Event::handle('StartIoManagerClasses', array(&$classes))) {
$classes[] = 'QueueManager';
if (common_config('xmpp', 'enabled')) {
$classes[] = 'XmppManager'; // handles pings/reconnects
$classes[] = 'XmppConfirmManager'; // polls for outgoing confirmations
}
}
Event::handle('EndIoManagerClasses', array(&$classes));
foreach ($classes as $class) {
$this->instantiate($class);
}
}
}
/**
* Pull all local sites from status_network table.
* @return array of hostnames
*/
protected function findAllSites()
{
$hosts = array();
$sn = new Status_network();
$sn->find();
while ($sn->fetch()) {
$hosts[] = $sn->hostname;
}
return $hosts;
}
/**
* Instantiate an i/o manager class for the current site.
* If a multi-site capable handler is already present,
* we don't need to build a new one.
*
* @param string $class
*/
protected function instantiate($class)
{
if (isset($this->singletons[$class])) {
// Already instantiated a multi-site-capable handler.
// Just let it know it should listen to this site too!
$this->singletons[$class]->addSite(common_config('site', 'server'));
return;
}
$manager = $this->getManager($class);
if ($this->multiSite) {
$caps = $manager->multiSite();
if ($caps == IoManager::SINGLE_ONLY) {
throw new Exception("$class can't run with --all; aborting.");
}
if ($caps == IoManager::INSTANCE_PER_PROCESS) {
// Save this guy for later!
// We'll only need the one to cover multiple sites.
$this->singletons[$class] = $manager;
$manager->addSite(common_config('site', 'server'));
}
}
$this->managers[] = $manager;
}
protected function getManager($class)
{
return call_user_func(array($class, 'get'));
}
/**
* Basic run loop...
*
* Initialize all io managers, then sit around waiting for input.
* Between events or timeouts, pass control back to idle() method
* to allow for any additional background processing.
*/
function service()
{
$this->logState('init');
$this->start();
while (true) {
$timeouts = array_values($this->pollTimeouts);
$timeouts[] = 60; // default max timeout
// Wait for something on one of our sockets
$sockets = array();
$managers = array();
foreach ($this->managers as $manager) {
foreach ($manager->getSockets() as $socket) {
$sockets[] = $socket;
$managers[] = $manager;
}
$timeouts[] = intval($manager->timeout());
}
$timeout = min($timeouts);
if ($sockets) {
$read = $sockets;
$write = array();
$except = array();
$this->logState('listening');
common_log(LOG_INFO, "Waiting up to $timeout seconds for socket data...");
$ready = stream_select($read, $write, $except, $timeout, 0);
if ($ready === false) {
common_log(LOG_ERR, "Error selecting on sockets");
} else if ($ready > 0) {
foreach ($read as $socket) {
$index = array_search($socket, $sockets, true);
if ($index !== false) {
$this->logState('queue');
$managers[$index]->handleInput($socket);
} else {
common_log(LOG_ERR, "Saw input on a socket we didn't listen to");
}
}
}
}
if ($timeout > 0 && empty($sockets)) {
// If we had no listeners, sleep until the pollers' next requested wakeup.
common_log(LOG_INFO, "Sleeping $timeout seconds until next poll cycle...");
$this->logState('sleep');
sleep($timeout);
}
$this->logState('poll');
$this->poll();
$this->logState('idle');
$this->idle();
$memoryLimit = $this->softMemoryLimit();
if ($memoryLimit > 0) {
$usage = memory_get_usage();
if ($usage > $memoryLimit) {
common_log(LOG_INFO, "Queue thread hit soft memory limit ($usage > $memoryLimit); gracefully restarting.");
break;
}
}
}
$this->logState('shutdown');
$this->finish();
}
/**
* Return fully-parsed soft memory limit in bytes.
* @return intval 0 or -1 if not set
*/
function softMemoryLimit()
{
$softLimit = trim(common_config('queue', 'softlimit'));
if (substr($softLimit, -1) == '%') {
$limit = trim(ini_get('memory_limit'));
$limit = $this->parseMemoryLimit($limit);
if ($limit > 0) {
return intval(substr($softLimit, 0, -1) * $limit / 100);
} else {
return -1;
}
} else {
return $this->parseMemoryLimit($limit);
}
return $softLimit;
}
/**
* Interpret PHP shorthand for memory_limit and friends.
* Why don't they just expose the actual numeric value? :P
* @param string $mem
* @return int
*/
protected function parseMemoryLimit($mem)
{
// http://www.php.net/manual/en/faq.using.php#faq.using.shorthandbytes
$size = array('k' => 1024,
'm' => 1024*1024,
'g' => 1024*1024*1024);
if (empty($mem)) {
return 0;
} else if (is_numeric($mem)) {
return intval($mem);
} else {
$mult = strtolower(substr($mem, -1));
if (isset($size[$mult])) {
return substr($mem, 0, -1) * $size[$mult];
} else {
return intval($mem);
}
}
}
function start()
{
foreach ($this->managers as $index => $manager) {
$manager->start($this);
// @fixme error check
if ($manager->pollInterval()) {
// We'll want to check for input on the first pass
$this->pollTimeouts[$index] = 0;
$this->lastPoll[$index] = 0;
}
}
}
function finish()
{
foreach ($this->managers as $manager) {
$manager->finish();
// @fixme error check
}
}
/**
* Called during the idle portion of the runloop to see which handlers
*/
function poll()
{
foreach ($this->managers as $index => $manager) {
$interval = $manager->pollInterval();
if ($interval <= 0) {
// Not a polling manager.
continue;
}
if (isset($this->pollTimeouts[$index])) {
$timeout = $this->pollTimeouts[$index];
if (time() - $this->lastPoll[$index] < $timeout) {
// Not time to poll yet.
continue;
}
} else {
$timeout = 0;
}
$hit = $manager->poll();
$this->lastPoll[$index] = time();
if ($hit) {
// Do the next poll quickly, there may be more input!
$this->pollTimeouts[$index] = 0;
} else {
// Empty queue. Exponential backoff up to the maximum poll interval.
if ($timeout > 0) {
$timeout = min($timeout * 2, $interval);
} else {
$timeout = 1;
}
$this->pollTimeouts[$index] = $timeout;
}
}
}
/**
* Called after each handled item or empty polling cycle.
* This is a good time to e.g. service your XMPP connection.
*/
function idle()
{
foreach ($this->managers as $manager) {
$manager->idle();
}
}
/**
* Send thread state update to the monitoring server, if configured.
*
* @param string $state ('init', 'queue', 'shutdown' etc)
* @param string $substate (optional, eg queue name 'omb' 'sms' etc)
*/
protected function logState($state, $substate='')
{
$this->monitor->logState($this->id, $state, $substate);
}
/**
* Send thread stats.
* Thread ID will be implicit; other owners can be listed as well
* for per-queue and per-site records.
*
* @param string $key counter name
* @param array $owners list of owner keys like 'queue:jabber' or 'site:stat01'
*/
public function stats($key, $owners=array())
{
$owners[] = "thread:" . $this->id;
$this->monitor->stats($key, $owners);
}
}