includes/job/JobQueueGroup.php

   1 <?php
   2 /**
   3  * Job queue base code.
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; either version 2 of the License, or
   8  * (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License along
  16  * with this program; if not, write to the Free Software Foundation, Inc.,
  17  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  18  * http://www.gnu.org/copyleft/gpl.html
  19  *
  20  * @file
  21  * @author Aaron Schulz
  22  */
  23
  24 /**
  25  * Class to handle enqueueing of background jobs
  26  *
  27  * @ingroup JobQueue
  28  * @since 1.21
  29  */
  30 class JobQueueGroup {
  31         /** @var Array */
  32         protected static $instances = array();
  33
  34         /** @var ProcessCacheLRU */
  35         protected $cache;
  36
  37         protected $wiki; // string; wiki ID
  38
  39         const TYPE_DEFAULT = 1; // integer; jobs popped by default
  40         const TYPE_ANY = 2; // integer; any job
  41
  42         const USE_CACHE = 1; // integer; use process or persistent cache
  43         const USE_PRIORITY = 2; // integer; respect deprioritization
  44
  45         const PROC_CACHE_TTL = 15; // integer; seconds
  46
  47         const CACHE_VERSION = 1; // integer; cache version
  48
  49         /**
  50          * @param string $wiki Wiki ID
  51          */
  52         protected function __construct( $wiki ) {
  53                 $this->wiki = $wiki;
  54                 $this->cache = new ProcessCacheLRU( 10 );
  55         }
  56
  57         /**
  58          * @param string $wiki Wiki ID
  59          * @return JobQueueGroup
  60          */
  61         public static function singleton( $wiki = false ) {
  62                 $wiki = ( $wiki === false ) ? wfWikiID() : $wiki;
  63                 if ( !isset( self::$instances[$wiki] ) ) {
  64                         self::$instances[$wiki] = new self( $wiki );
  65                 }
  66                 return self::$instances[$wiki];
  67         }
  68
  69         /**
  70          * Destroy the singleton instances
  71          *
  72          * @return void
  73          */
  74         public static function destroySingletons() {
  75                 self::$instances = array();
  76         }
  77
  78         /**
  79          * Get the job queue object for a given queue type
  80          *
  81          * @param $type string
  82          * @return JobQueue
  83          */
  84         public function get( $type ) {
  85                 global $wgJobTypeConf;
  86
  87                 $conf = array( 'wiki' => $this->wiki, 'type' => $type );
  88                 if ( isset( $wgJobTypeConf[$type] ) ) {
  89                         $conf = $conf + $wgJobTypeConf[$type];
  90                 } else {
  91                         $conf = $conf + $wgJobTypeConf['default'];
  92                 }
  93
  94                 return JobQueue::factory( $conf );
  95         }
  96
  97         /**
  98          * Insert jobs into the respective queues of with the belong.
  99          *
 100          * This inserts the jobs into the queue specified by $wgJobTypeConf
 101          * and updates the aggregate job queue information cache as needed.
 102          *
 103          * @param $jobs Job|array A single Job or a list of Jobs
 104          * @throws MWException
 105          * @return bool
 106          */
 107         public function push( $jobs ) {
 108                 $jobs = is_array( $jobs ) ? $jobs : array( $jobs );
 109
 110                 $jobsByType = array(); // (job type => list of jobs)
 111                 foreach ( $jobs as $job ) {
 112                         if ( $job instanceof Job ) {
 113                                 $jobsByType[$job->getType()][] = $job;
 114                         } else {
 115                                 throw new MWException( "Attempted to push a non-Job object into a queue." );
 116                         }
 117                 }
 118
 119                 $ok = true;
 120                 foreach ( $jobsByType as $type => $jobs ) {
 121                         if ( $this->get( $type )->push( $jobs ) ) {
 122                                 JobQueueAggregator::singleton()->notifyQueueNonEmpty( $this->wiki, $type );
 123                         } else {
 124                                 $ok = false;
 125                         }
 126                 }
 127
 128                 if ( $this->cache->has( 'queues-ready', 'list' ) ) {
 129                         $list = $this->cache->get( 'queues-ready', 'list' );
 130                         if ( count( array_diff( array_keys( $jobsByType ), $list ) ) ) {
 131                                 $this->cache->clear( 'queues-ready' );
 132                         }
 133                 }
 134
 135                 return $ok;
 136         }
 137
 138         /**
 139          * Pop a job off one of the job queues
 140          *
 141          * This pops a job off a queue as specified by $wgJobTypeConf and
 142          * updates the aggregate job queue information cache as needed.
 143          *
 144          * @param $qtype integer|string JobQueueGroup::TYPE_DEFAULT or type string
 145          * @param $flags integer Bitfield of JobQueueGroup::USE_* constants
 146          * @return Job|bool Returns false on failure
 147          */
 148         public function pop( $qtype = self::TYPE_DEFAULT, $flags = 0 ) {
 149                 if ( is_string( $qtype ) ) { // specific job type
 150                         if ( ( $flags & self::USE_PRIORITY ) && $this->isQueueDeprioritized( $qtype ) ) {
 151                                 return false; // back off
 152                         }
 153                         $job = $this->get( $qtype )->pop();
 154                         if ( !$job ) {
 155                                 JobQueueAggregator::singleton()->notifyQueueEmpty( $this->wiki, $qtype );
 156                         }
 157                         return $job;
 158                 } else { // any job in the "default" jobs types
 159                         if ( $flags & self::USE_CACHE ) {
 160                                 if ( !$this->cache->has( 'queues-ready', 'list', self::PROC_CACHE_TTL ) ) {
 161                                         $this->cache->set( 'queues-ready', 'list', $this->getQueuesWithJobs() );
 162                                 }
 163                                 $types = $this->cache->get( 'queues-ready', 'list' );
 164                         } else {
 165                                 $types = $this->getQueuesWithJobs();
 166                         }
 167
 168                         if ( $qtype == self::TYPE_DEFAULT ) {
 169                                 $types = array_intersect( $types, $this->getDefaultQueueTypes() );
 170                         }
 171                         shuffle( $types ); // avoid starvation
 172
 173                         foreach ( $types as $type ) { // for each queue...
 174                                 if ( ( $flags & self::USE_PRIORITY ) && $this->isQueueDeprioritized( $type ) ) {
 175                                         continue; // back off
 176                                 }
 177                                 $job = $this->get( $type )->pop();
 178                                 if ( $job ) { // found
 179                                         return $job;
 180                                 } else { // not found
 181                                         JobQueueAggregator::singleton()->notifyQueueEmpty( $this->wiki, $type );
 182                                         $this->cache->clear( 'queues-ready' );
 183                                 }
 184                         }
 185
 186                         return false; // no jobs found
 187                 }
 188         }
 189
 190         /**
 191          * Acknowledge that a job was completed
 192          *
 193          * @param $job Job
 194          * @return bool
 195          */
 196         public function ack( Job $job ) {
 197                 return $this->get( $job->getType() )->ack( $job );
 198         }
 199
 200         /**
 201          * Register the "root job" of a given job into the queue for de-duplication.
 202          * This should only be called right *after* all the new jobs have been inserted.
 203          *
 204          * @param $job Job
 205          * @return bool
 206          */
 207         public function deduplicateRootJob( Job $job ) {
 208                 return $this->get( $job->getType() )->deduplicateRootJob( $job );
 209         }
 210
 211         /**
 212          * Wait for any slaves or backup queue servers to catch up.
 213          *
 214          * This does nothing for certain queue classes.
 215          *
 216          * @return void
 217          * @throws MWException
 218          */
 219         public function waitForBackups() {
 220                 global $wgJobTypeConf;
 221
 222                 wfProfileIn( __METHOD__ );
 223                 // Try to avoid doing this more than once per queue storage medium
 224                 foreach ( $wgJobTypeConf as $type => $conf ) {
 225                         $this->get( $type )->waitForBackups();
 226                 }
 227                 wfProfileOut( __METHOD__ );
 228         }
 229
 230         /**
 231          * Get the list of queue types
 232          *
 233          * @return array List of strings
 234          */
 235         public function getQueueTypes() {
 236                 return array_keys( $this->getCachedConfigVar( 'wgJobClasses' ) );
 237         }
 238
 239         /**
 240          * Get the list of default queue types
 241          *
 242          * @return array List of strings
 243          */
 244         public function getDefaultQueueTypes() {
 245                 global $wgJobTypesExcludedFromDefaultQueue;
 246
 247                 return array_diff( $this->getQueueTypes(), $wgJobTypesExcludedFromDefaultQueue );
 248         }
 249
 250         /**
 251          * Get the list of job types that have non-empty queues
 252          *
 253          * @return Array List of job types that have non-empty queues
 254          */
 255         public function getQueuesWithJobs() {
 256                 $types = array();
 257                 foreach ( $this->getQueueTypes() as $type ) {
 258                         if ( !$this->get( $type )->isEmpty() ) {
 259                                 $types[] = $type;
 260                         }
 261                 }
 262                 return $types;
 263         }
 264
 265         /**
 266          * Check if jobs should not be popped of a queue right now.
 267          * This is only used for performance, such as to avoid spamming
 268          * the queue with many sub-jobs before they actually get run.
 269          *
 270          * @param $type string
 271          * @return bool
 272          */
 273         public function isQueueDeprioritized( $type ) {
 274                 if ( $this->cache->has( 'isDeprioritized', $type, 5 ) ) {
 275                         return $this->cache->get( 'isDeprioritized', $type );
 276                 }
 277                 if ( $type === 'refreshLinks2' ) {
 278                         // Don't keep converting refreshLinks2 => refreshLinks jobs if the
 279                         // later jobs have not been done yet. This helps throttle queue spam.
 280                         $deprioritized = !$this->get( 'refreshLinks' )->isEmpty();
 281                         $this->cache->set( 'isDeprioritized', $type, $deprioritized );
 282                         return $deprioritized;
 283                 }
 284                 return false;
 285         }
 286
 287         /**
 288          * Execute any due periodic queue maintenance tasks for all queues.
 289          *
 290          * A task is "due" if the time ellapsed since the last run is greater than
 291          * the defined run period. Concurrent calls to this function will cause tasks
 292          * to be attempted twice, so they may need their own methods of mutual exclusion.
 293          *
 294          * @return integer Number of tasks run
 295          */
 296         public function executeReadyPeriodicTasks() {
 297                 global $wgMemc;
 298
 299                 list( $db, $prefix ) = wfSplitWikiID( $this->wiki );
 300                 $key = wfForeignMemcKey( $db, $prefix, 'jobqueuegroup', 'taskruns', 'v1' );
 301                 $lastRuns = $wgMemc->get( $key ); // (queue => task => UNIX timestamp)
 302
 303                 $count = 0;
 304                 $tasksRun = array(); // (queue => task => UNIX timestamp)
 305                 foreach ( $this->getQueueTypes() as $type ) {
 306                         $queue = $this->get( $type );
 307                         foreach ( $queue->getPeriodicTasks() as $task => $definition ) {
 308                                 if ( $definition['period'] <= 0 ) {
 309                                         continue; // disabled
 310                                 } elseif ( !isset( $lastRuns[$type][$task] )
 311                                         || $lastRuns[$type][$task] < ( time() - $definition['period'] ) )
 312                                 {
 313                                         if ( call_user_func( $definition['callback'] ) !== null ) {
 314                                                 $tasksRun[$type][$task] = time();
 315                                                 ++$count;
 316                                         }
 317                                 }
 318                         }
 319                 }
 320
 321                 $wgMemc->merge( $key, function( $cache, $key, $lastRuns ) use ( $tasksRun ) {
 322                         if ( is_array( $lastRuns ) ) {
 323                                 foreach ( $tasksRun as $type => $tasks ) {
 324                                         foreach ( $tasks as $task => $timestamp ) {
 325                                                 if ( !isset( $lastRuns[$type][$task] )
 326                                                         || $timestamp > $lastRuns[$type][$task] )
 327                                                 {
 328                                                         $lastRuns[$type][$task] = $timestamp;
 329                                                 }
 330                                         }
 331                                 }
 332                         } else {
 333                                 $lastRuns = $tasksRun;
 334                         }
 335                         return $lastRuns;
 336                 } );
 337
 338                 return $count;
 339         }
 340
 341         /**
 342          * @param $name string
 343          * @return mixed
 344          */
 345         private function getCachedConfigVar( $name ) {
 346                 global $wgConf, $wgMemc;
 347
 348                 if ( $this->wiki === wfWikiID() ) {
 349                         return $GLOBALS[$name]; // common case
 350                 } else {
 351                         list( $db, $prefix ) = wfSplitWikiID( $this->wiki );
 352                         $key = wfForeignMemcKey( $db, $prefix, 'configvalue', $name );
 353                         $value = $wgMemc->get( $key ); // ('v' => ...) or false
 354                         if ( is_array( $value ) ) {
 355                                 return $value['v'];
 356                         } else {
 357                                 $value = $wgConf->getConfig( $this->wiki, $name );
 358                                 $wgMemc->set( $key, array( 'v' => $value ), 86400 + mt_rand( 0, 86400 ) );
 359                                 return $value;
 360                         }
 361                 }
 362         }
 363 }