iomaster.php 11.1 KB
Newer Older
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29
<?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/
 */

30
abstract class IoMaster
31 32 33 34 35 36 37 38 39 40
{
    public $id;

    protected $multiSite = false;
    protected $managers = array();
    protected $singletons = array();

    protected $pollTimeouts = array();
    protected $lastPoll = array();

41 42 43
    public $shutdown = false; // Did we do a graceful shutdown?
    public $respawn = true; // Should we respawn after shutdown?

44 45 46 47 48 49 50 51 52 53 54 55 56 57 58
    /**
     * @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;
        }

59
        $this->initManagers();
60 61
    }

62
    /**
63 64 65 66 67
     * Initialize IoManagers which are appropriate to this instance;
     * pass class names or instances into $this->instantiate().
     *
     * If setup and configuration may vary between sites in multi-site
     * mode, it's the subclass's responsibility to set them up here.
68
     *
69
     * Switching site configurations is an acceptable side effect.
70 71 72
     */
    abstract function initManagers();

73 74 75 76 77
    /**
     * 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.
     *
78
     * @param mixed $manager class name (to run $class::get()) or object
79
     */
80
    protected function instantiate($manager)
81
    {
82 83
        if (is_string($manager)) {
            $manager = call_user_func(array($class, 'get'));
84 85
        }

86 87 88
        $caps = $manager->multiSite();
        if ($caps == IoManager::SINGLE_ONLY) {
            if ($this->multiSite) {
89 90
                throw new Exception("$class can't run with --all; aborting.");
            }
91 92
        } else if ($caps == IoManager::INSTANCE_PER_PROCESS) {
            $manager->addSite();
93 94
        }

95 96 97
        if (!in_array($manager, $this->managers, true)) {
            // Only need to save singletons once
            $this->managers[] = $manager;
98
        }
99 100 101 102 103 104 105 106 107 108 109 110 111
    }

    /**
     * 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();
112
        $this->checkMemory(false);
113

114
        while (!$this->shutdown) {
115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134
            $timeouts = array_values($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');
135
                //common_debug("Waiting up to $timeout seconds for socket data...");
136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154
                $ready = stream_select($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.
155
                common_log(LOG_DEBUG, "Sleeping $timeout seconds until next poll cycle...");
156 157 158 159 160 161 162 163 164 165
                $this->logState('sleep');
                sleep($timeout);
            }

            $this->logState('poll');
            $this->poll();

            $this->logState('idle');
            $this->idle();

166
            $this->checkMemory();
167 168 169 170 171 172
        }

        $this->logState('shutdown');
        $this->finish();
    }

173 174 175
    /**
     * Check runtime memory usage, possibly triggering a graceful shutdown
     * and thread respawn if we've crossed the soft limit.
176 177
     *
     * @param boolean $respawn if false we'll shut down instead of respawning
178
     */
179
    protected function checkMemory($respawn=true)
180 181 182 183 184 185
    {
        $memoryLimit = $this->softMemoryLimit();
        if ($memoryLimit > 0) {
            $usage = memory_get_usage();
            if ($usage > $memoryLimit) {
                common_log(LOG_INFO, "Queue thread hit soft memory limit ($usage > $memoryLimit); gracefully restarting.");
186 187 188 189 190
                if ($respawn) {
                    $this->requestRestart();
                } else {
                    $this->requestShutdown();
                }
191
            } else if (common_config('queue', 'debug_memory')) {
192 193
                $fmt = number_format($usage);
                common_log(LOG_DEBUG, "Memory usage $fmt");
194 195 196 197
            }
        }
    }

198 199 200 201 202 203 204 205
    /**
     * 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) == '%') {
206
            $limit = $this->parseMemoryLimit(ini_get('memory_limit'));
207 208 209 210 211 212
            if ($limit > 0) {
                return intval(substr($softLimit, 0, -1) * $limit / 100);
            } else {
                return -1;
            }
        } else {
213
            return $this->parseMemoryLimit($softLimit);
214 215 216 217 218 219 220 221 222 223
        }
        return $softLimit;
    }

    /**
     * Interpret PHP shorthand for memory_limit and friends.
     * Why don't they just expose the actual numeric value? :P
     * @param string $mem
     * @return int
     */
224
    public function parseMemoryLimit($mem)
225 226
    {
        // http://www.php.net/manual/en/faq.using.php#faq.using.shorthandbytes
227
        $mem = strtolower(trim($mem));
228 229 230 231 232 233 234 235
        $size = array('k' => 1024,
                      'm' => 1024*1024,
                      'g' => 1024*1024*1024);
        if (empty($mem)) {
            return 0;
        } else if (is_numeric($mem)) {
            return intval($mem);
        } else {
236
            $mult = substr($mem, -1);
237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332
            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
333
     * @param array $owners list of owner keys like 'queue:xmpp' or 'site:stat01'
334 335 336 337 338 339
     */
    public function stats($key, $owners=array())
    {
        $owners[] = "thread:" . $this->id;
        $this->monitor->stats($key, $owners);
    }
340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358

    /**
     * For IoManagers to request a graceful shutdown at end of event loop.
     */
    public function requestShutdown()
    {
        $this->shutdown = true;
        $this->respawn = false;
    }

    /**
     * For IoManagers to request a graceful restart at end of event loop.
     */
    public function requestRestart()
    {
        $this->shutdown = true;
        $this->respawn = true;
    }

359 360
}