includes/job/JobQueueRedis.php

   1 <?php
   2 /**
   3  * Redis-backed job queue 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 job queues stored in Redis
  26  *
  27  * This is faster, less resource intensive, queue that JobQueueDB.
  28  * All data for a queue using this class is placed into one redis server.
  29  *
  30  * There are eight main redis keys used to track jobs:
  31  *   - l-unclaimed  : A list of job IDs used for ready unclaimed jobs
  32  *   - z-claimed    : A sorted set of (job ID, UNIX timestamp as score) used for job retries
  33  *   - z-abandoned  : A sorted set of (job ID, UNIX timestamp as score) used for broken jobs
  34  *   - z-delayed    : A sorted set of (job ID, UNIX timestamp as score) used for delayed jobs
  35  *   - h-idBySha1   : A hash of (SHA1 => job ID) for unclaimed jobs used for de-duplication
  36  *   - h-sha1ById   : A hash of (job ID => SHA1) for unclaimed jobs used for de-duplication
  37  *   - h-attempts   : A hash of (job ID => attempt count) used for job claiming/retries
  38  *   - h-data       : A hash of (job ID => serialized blobs) for job storage
  39  * A job ID can be in only one of z-delayed, l-unclaimed, z-claimed, and z-abandoned.
  40  * If an ID appears in any of those lists, it should have a h-data entry for its ID.
  41  * If a job has a SHA1 de-duplication value and its ID is in l-unclaimed or z-delayed, then
  42  * there should be no other such jobs with that SHA1. Every h-idBySha1 entry has an h-sha1ById
  43  * entry and every h-sha1ById must refer to an ID that is l-unclaimed. If a job has its
  44  * ID in z-claimed or z-abandoned, then it must also have an h-attempts entry for its ID.
  45  *
  46  * Additionally, "rootjob:* keys track "root jobs" used for additional de-duplication.
  47  * Aside from root job keys, all keys have no expiry, and are only removed when jobs are run.
  48  * All the keys are prefixed with the relevant wiki ID information.
  49  *
  50  * This class requires Redis 2.6 as it makes use Lua scripts for fast atomic operations.
  51  * Additionally, it should be noted that redis has different persistence modes, such
  52  * as rdb snapshots, journaling, and no persistent. Appropriate configuration should be
  53  * made on the servers based on what queues are using it and what tolerance they have.
  54  *
  55  * @ingroup JobQueue
  56  * @ingroup Redis
  57  * @since 1.22
  58  */
  59 class JobQueueRedis extends JobQueue {
  60         /** @var RedisConnectionPool */
  61         protected $redisPool;
  62
  63         /** @var string Server address */
  64         protected $server;
  65
  66         /** @var string Compression method to use */
  67         protected $compression;
  68
  69         const MAX_AGE_PRUNE = 604800; // integer; seconds a job can live once claimed (7 days)
  70
  71         /** @var string Key to prefix the queue keys with (used for testing) */
  72         protected $key;
  73
  74         /**
  75          * @params include:
  76          *   - redisConfig : An array of parameters to RedisConnectionPool::__construct().
  77          *                   Note that the serializer option is ignored as "none" is always used.
  78          *   - redisServer : A hostname/port combination or the absolute path of a UNIX socket.
  79          *                   If a hostname is specified but no port, the standard port number
  80          *                   6379 will be used. Required.
  81          *   - compression : The type of compression to use; one of (none,gzip).
  82          * @param array $params
  83          */
  84         public function __construct( array $params ) {
  85                 parent::__construct( $params );
  86                 $params['redisConfig']['serializer'] = 'none'; // make it easy to use Lua
  87                 $this->server = $params['redisServer'];
  88                 $this->compression = isset( $params['compression'] ) ? $params['compression'] : 'none';
  89                 $this->redisPool = RedisConnectionPool::singleton( $params['redisConfig'] );
  90         }
  91
  92         protected function supportedOrders() {
  93                 return array( 'timestamp', 'fifo' );
  94         }
  95
  96         protected function optimalOrder() {
  97                 return 'fifo';
  98         }
  99
 100         protected function supportsDelayedJobs() {
 101                 return true;
 102         }
 103
 104         /**
 105          * @see JobQueue::doIsEmpty()
 106          * @return bool
 107          * @throws MWException
 108          */
 109         protected function doIsEmpty() {
 110                 return $this->doGetSize() == 0;
 111         }
 112
 113         /**
 114          * @see JobQueue::doGetSize()
 115          * @return int
 116          * @throws MWException
 117          */
 118         protected function doGetSize() {
 119                 $conn = $this->getConnection();
 120                 try {
 121                         return $conn->lSize( $this->getQueueKey( 'l-unclaimed' ) );
 122                 } catch ( RedisException $e ) {
 123                         $this->throwRedisException( $this->server, $conn, $e );
 124                 }
 125         }
 126
 127         /**
 128          * @see JobQueue::doGetAcquiredCount()
 129          * @return int
 130          * @throws JobQueueError
 131          */
 132         protected function doGetAcquiredCount() {
 133                 if ( $this->claimTTL <= 0 ) {
 134                         return 0; // no acknowledgements
 135                 }
 136                 $conn = $this->getConnection();
 137                 try {
 138                         $conn->multi( Redis::PIPELINE );
 139                         $conn->zSize( $this->getQueueKey( 'z-claimed' ) );
 140                         $conn->zSize( $this->getQueueKey( 'z-abandoned' ) );
 141
 142                         return array_sum( $conn->exec() );
 143                 } catch ( RedisException $e ) {
 144                         $this->throwRedisException( $this->server, $conn, $e );
 145                 }
 146         }
 147
 148         /**
 149          * @see JobQueue::doGetDelayedCount()
 150          * @return int
 151          * @throws JobQueueError
 152          */
 153         protected function doGetDelayedCount() {
 154                 if ( !$this->checkDelay ) {
 155                         return 0; // no delayed jobs
 156                 }
 157                 $conn = $this->getConnection();
 158                 try {
 159                         return $conn->zSize( $this->getQueueKey( 'z-delayed' ) );
 160                 } catch ( RedisException $e ) {
 161                         $this->throwRedisException( $this->server, $conn, $e );
 162                 }
 163         }
 164
 165         /**
 166          * @see JobQueue::doGetAbandonedCount()
 167          * @return int
 168          * @throws JobQueueError
 169          */
 170         protected function doGetAbandonedCount() {
 171                 if ( $this->claimTTL <= 0 ) {
 172                         return 0; // no acknowledgements
 173                 }
 174                 $conn = $this->getConnection();
 175                 try {
 176                         return $conn->zSize( $this->getQueueKey( 'z-abandoned' ) );
 177                 } catch ( RedisException $e ) {
 178                         $this->throwRedisException( $this->server, $conn, $e );
 179                 }
 180         }
 181
 182         /**
 183          * @see JobQueue::doBatchPush()
 184          * @param array $jobs
 185          * @param $flags
 186          * @return bool
 187          * @throws JobQueueError
 188          */
 189         protected function doBatchPush( array $jobs, $flags ) {
 190                 // Convert the jobs into field maps (de-duplicated against each other)
 191                 $items = array(); // (job ID => job fields map)
 192                 foreach ( $jobs as $job ) {
 193                         $item = $this->getNewJobFields( $job );
 194                         if ( strlen( $item['sha1'] ) ) { // hash identifier => de-duplicate
 195                                 $items[$item['sha1']] = $item;
 196                         } else {
 197                                 $items[$item['uuid']] = $item;
 198                         }
 199                 }
 200
 201                 if ( !count( $items ) ) {
 202                         return true; // nothing to do
 203                 }
 204
 205                 $conn = $this->getConnection();
 206                 try {
 207                         // Actually push the non-duplicate jobs into the queue...
 208                         if ( $flags & self::QOS_ATOMIC ) {
 209                                 $batches = array( $items ); // all or nothing
 210                         } else {
 211                                 $batches = array_chunk( $items, 500 ); // avoid tying up the server
 212                         }
 213                         $failed = 0;
 214                         $pushed = 0;
 215                         foreach ( $batches as $itemBatch ) {
 216                                 $added = $this->pushBlobs( $conn, $itemBatch );
 217                                 if ( is_int( $added ) ) {
 218                                         $pushed += $added;
 219                                 } else {
 220                                         $failed += count( $itemBatch );
 221                                 }
 222                         }
 223                         if ( $failed > 0 ) {
 224                                 wfDebugLog( 'JobQueueRedis', "Could not insert {$failed} {$this->type} job(s)." );
 225
 226                                 return false;
 227                         }
 228                         JobQueue::incrStats( 'job-insert', $this->type, count( $items ) );
 229                         JobQueue::incrStats( 'job-insert-duplicate', $this->type,
 230                                 count( $items ) - $failed - $pushed );
 231                 } catch ( RedisException $e ) {
 232                         $this->throwRedisException( $this->server, $conn, $e );
 233                 }
 234
 235                 return true;
 236         }
 237
 238         /**
 239          * @param RedisConnRef $conn
 240          * @param array $items List of results from JobQueueRedis::getNewJobFields()
 241          * @return int Number of jobs inserted (duplicates are ignored)
 242          * @throws RedisException
 243          */
 244         protected function pushBlobs( RedisConnRef $conn, array $items ) {
 245                 $args = array(); // ([id, sha1, rtime, blob [, id, sha1, rtime, blob ... ] ] )
 246                 foreach ( $items as $item ) {
 247                         $args[] = (string)$item['uuid'];
 248                         $args[] = (string)$item['sha1'];
 249                         $args[] = (string)$item['rtimestamp'];
 250                         $args[] = (string)$this->serialize( $item );
 251                 }
 252                 static $script =
 253 <<<LUA
 254                 if #ARGV % 4 ~= 0 then return redis.error_reply('Unmatched arguments') end
 255                 local pushed = 0
 256                 for i = 1,#ARGV,4 do
 257                         local id,sha1,rtimestamp,blob = ARGV[i],ARGV[i+1],ARGV[i+2],ARGV[i+3]
 258                         if sha1 == '' or redis.call('hExists',KEYS[3],sha1) == 0 then
 259                                 if 1*rtimestamp > 0 then
 260                                         -- Insert into delayed queue (release time as score)
 261                                         redis.call('zAdd',KEYS[4],rtimestamp,id)
 262                                 else
 263                                         -- Insert into unclaimed queue
 264                                         redis.call('lPush',KEYS[1],id)
 265                                 end
 266                                 if sha1 ~= '' then
 267                                         redis.call('hSet',KEYS[2],id,sha1)
 268                                         redis.call('hSet',KEYS[3],sha1,id)
 269                                 end
 270                                 redis.call('hSet',KEYS[5],id,blob)
 271                                 pushed = pushed + 1
 272                         end
 273                 end
 274                 return pushed
 275 LUA;
 276                 return $conn->luaEval( $script,
 277                         array_merge(
 278                                 array(
 279                                         $this->getQueueKey( 'l-unclaimed' ), # KEYS[1]
 280                                         $this->getQueueKey( 'h-sha1ById' ), # KEYS[2]
 281                                         $this->getQueueKey( 'h-idBySha1' ), # KEYS[3]
 282                                         $this->getQueueKey( 'z-delayed' ), # KEYS[4]
 283                                         $this->getQueueKey( 'h-data' ), # KEYS[5]
 284                                 ),
 285                                 $args
 286                         ),
 287                         5 # number of first argument(s) that are keys
 288                 );
 289         }
 290
 291         /**
 292          * @see JobQueue::doPop()
 293          * @return Job|bool
 294          * @throws JobQueueError
 295          */
 296         protected function doPop() {
 297                 $job = false;
 298
 299                 // Push ready delayed jobs into the queue every 10 jobs to spread the load.
 300                 // This is also done as a periodic task, but we don't want too much done at once.
 301                 if ( $this->checkDelay && mt_rand( 0, 9 ) == 0 ) {
 302                         $this->releaseReadyDelayedJobs();
 303                 }
 304
 305                 $conn = $this->getConnection();
 306                 try {
 307                         do {
 308                                 if ( $this->claimTTL > 0 ) {
 309                                         // Keep the claimed job list down for high-traffic queues
 310                                         if ( mt_rand( 0, 99 ) == 0 ) {
 311                                                 $this->recycleAndDeleteStaleJobs();
 312                                         }
 313                                         $blob = $this->popAndAcquireBlob( $conn );
 314                                 } else {
 315                                         $blob = $this->popAndDeleteBlob( $conn );
 316                                 }
 317                                 if ( $blob === false ) {
 318                                         break; // no jobs; nothing to do
 319                                 }
 320
 321                                 JobQueue::incrStats( 'job-pop', $this->type );
 322                                 $item = $this->unserialize( $blob );
 323                                 if ( $item === false ) {
 324                                         wfDebugLog( 'JobQueueRedis', "Could not unserialize {$this->type} job." );
 325                                         continue;
 326                                 }
 327
 328                                 // If $item is invalid, recycleAndDeleteStaleJobs() will cleanup as needed
 329                                 $job = $this->getJobFromFields( $item ); // may be false
 330                         } while ( !$job ); // job may be false if invalid
 331                 } catch ( RedisException $e ) {
 332                         $this->throwRedisException( $this->server, $conn, $e );
 333                 }
 334
 335                 return $job;
 336         }
 337
 338         /**
 339          * @param RedisConnRef $conn
 340          * @return array serialized string or false
 341          * @throws RedisException
 342          */
 343         protected function popAndDeleteBlob( RedisConnRef $conn ) {
 344                 static $script =
 345 <<<LUA
 346                 -- Pop an item off the queue
 347                 local id = redis.call('rpop',KEYS[1])
 348                 if not id then return false end
 349                 -- Get the job data and remove it
 350                 local item = redis.call('hGet',KEYS[4],id)
 351                 redis.call('hDel',KEYS[4],id)
 352                 -- Allow new duplicates of this job
 353                 local sha1 = redis.call('hGet',KEYS[2],id)
 354                 if sha1 then redis.call('hDel',KEYS[3],sha1) end
 355                 redis.call('hDel',KEYS[2],id)
 356                 -- Return the job data
 357                 return item
 358 LUA;
 359                 return $conn->luaEval( $script,
 360                         array(
 361                                 $this->getQueueKey( 'l-unclaimed' ), # KEYS[1]
 362                                 $this->getQueueKey( 'h-sha1ById' ), # KEYS[2]
 363                                 $this->getQueueKey( 'h-idBySha1' ), # KEYS[3]
 364                                 $this->getQueueKey( 'h-data' ), # KEYS[4]
 365                         ),
 366                         4 # number of first argument(s) that are keys
 367                 );
 368         }
 369
 370         /**
 371          * @param RedisConnRef $conn
 372          * @return array serialized string or false
 373          * @throws RedisException
 374          */
 375         protected function popAndAcquireBlob( RedisConnRef $conn ) {
 376                 static $script =
 377 <<<LUA
 378                 -- Pop an item off the queue
 379                 local id = redis.call('rPop',KEYS[1])
 380                 if not id then return false end
 381                 -- Allow new duplicates of this job
 382                 local sha1 = redis.call('hGet',KEYS[2],id)
 383                 if sha1 then redis.call('hDel',KEYS[3],sha1) end
 384                 redis.call('hDel',KEYS[2],id)
 385                 -- Mark the jobs as claimed and return it
 386                 redis.call('zAdd',KEYS[4],ARGV[1],id)
 387                 redis.call('hIncrBy',KEYS[5],id,1)
 388                 return redis.call('hGet',KEYS[6],id)
 389 LUA;
 390                 return $conn->luaEval( $script,
 391                         array(
 392                                 $this->getQueueKey( 'l-unclaimed' ), # KEYS[1]
 393                                 $this->getQueueKey( 'h-sha1ById' ), # KEYS[2]
 394                                 $this->getQueueKey( 'h-idBySha1' ), # KEYS[3]
 395                                 $this->getQueueKey( 'z-claimed' ), # KEYS[4]
 396                                 $this->getQueueKey( 'h-attempts' ), # KEYS[5]
 397                                 $this->getQueueKey( 'h-data' ), # KEYS[6]
 398                                 time(), # ARGV[1] (injected to be replication-safe)
 399                         ),
 400                         6 # number of first argument(s) that are keys
 401                 );
 402         }
 403
 404         /**
 405          * @see JobQueue::doAck()
 406          * @param Job $job
 407          * @return Job|bool
 408          * @throws MWException|JobQueueError
 409          */
 410         protected function doAck( Job $job ) {
 411                 if ( !isset( $job->metadata['uuid'] ) ) {
 412                         throw new MWException( "Job of type '{$job->getType()}' has no UUID." );
 413                 }
 414                 if ( $this->claimTTL > 0 ) {
 415                         $conn = $this->getConnection();
 416                         try {
 417                                 static $script =
 418 <<<LUA
 419                                 -- Unmark the job as claimed
 420                                 redis.call('zRem',KEYS[1],ARGV[1])
 421                                 redis.call('hDel',KEYS[2],ARGV[1])
 422                                 -- Delete the job data itself
 423                                 return redis.call('hDel',KEYS[3],ARGV[1])
 424 LUA;
 425                                 $res = $conn->luaEval( $script,
 426                                         array(
 427                                                 $this->getQueueKey( 'z-claimed' ), # KEYS[1]
 428                                                 $this->getQueueKey( 'h-attempts' ), # KEYS[2]
 429                                                 $this->getQueueKey( 'h-data' ), # KEYS[3]
 430                                                 $job->metadata['uuid'] # ARGV[1]
 431                                         ),
 432                                         3 # number of first argument(s) that are keys
 433                                 );
 434
 435                                 if ( !$res ) {
 436                                         wfDebugLog( 'JobQueueRedis', "Could not acknowledge {$this->type} job." );
 437
 438                                         return false;
 439                                 }
 440                         } catch ( RedisException $e ) {
 441                                 $this->throwRedisException( $this->server, $conn, $e );
 442                         }
 443                 }
 444
 445                 return true;
 446         }
 447
 448         /**
 449          * @see JobQueue::doDeduplicateRootJob()
 450          * @param Job $job
 451          * @return bool
 452          * @throws MWException|JobQueueError
 453          */
 454         protected function doDeduplicateRootJob( Job $job ) {
 455                 if ( !$job->hasRootJobParams() ) {
 456                         throw new MWException( "Cannot register root job; missing parameters." );
 457                 }
 458                 $params = $job->getRootJobParams();
 459
 460                 $key = $this->getRootJobCacheKey( $params['rootJobSignature'] );
 461
 462                 $conn = $this->getConnection();
 463                 try {
 464                         $timestamp = $conn->get( $key ); // current last timestamp of this job
 465                         if ( $timestamp && $timestamp >= $params['rootJobTimestamp'] ) {
 466                                 return true; // a newer version of this root job was enqueued
 467                         }
 468
 469                         // Update the timestamp of the last root job started at the location...
 470                         return $conn->set( $key, $params['rootJobTimestamp'], self::ROOTJOB_TTL ); // 2 weeks
 471                 } catch ( RedisException $e ) {
 472                         $this->throwRedisException( $this->server, $conn, $e );
 473                 }
 474         }
 475
 476         /**
 477          * @see JobQueue::doIsRootJobOldDuplicate()
 478          * @param Job $job
 479          * @return bool
 480          * @throws JobQueueError
 481          */
 482         protected function doIsRootJobOldDuplicate( Job $job ) {
 483                 if ( !$job->hasRootJobParams() ) {
 484                         return false; // job has no de-deplication info
 485                 }
 486                 $params = $job->getRootJobParams();
 487
 488                 $conn = $this->getConnection();
 489                 try {
 490                         // Get the last time this root job was enqueued
 491                         $timestamp = $conn->get( $this->getRootJobCacheKey( $params['rootJobSignature'] ) );
 492                 } catch ( RedisException $e ) {
 493                         $this->throwRedisException( $this->server, $conn, $e );
 494                 }
 495
 496                 // Check if a new root job was started at the location after this one's...
 497                 return ( $timestamp && $timestamp > $params['rootJobTimestamp'] );
 498         }
 499
 500         /**
 501          * @see JobQueue::doDelete()
 502          * @return bool
 503          * @throws JobQueueError
 504          */
 505         protected function doDelete() {
 506                 static $props = array( 'l-unclaimed', 'z-claimed', 'z-abandoned',
 507                         'z-delayed', 'h-idBySha1', 'h-sha1ById', 'h-attempts', 'h-data' );
 508
 509                 $conn = $this->getConnection();
 510                 try {
 511                         $keys = array();
 512                         foreach ( $props as $prop ) {
 513                                 $keys[] = $this->getQueueKey( $prop );
 514                         }
 515
 516                         return ( $conn->delete( $keys ) !== false );
 517                 } catch ( RedisException $e ) {
 518                         $this->throwRedisException( $this->server, $conn, $e );
 519                 }
 520         }
 521
 522         /**
 523          * @see JobQueue::getAllQueuedJobs()
 524          * @return Iterator
 525          */
 526         public function getAllQueuedJobs() {
 527                 $conn = $this->getConnection();
 528                 try {
 529                         $that = $this;
 530
 531                         return new MappedIterator(
 532                                 $conn->lRange( $this->getQueueKey( 'l-unclaimed' ), 0, -1 ),
 533                                 function ( $uid ) use ( $that, $conn ) {
 534                                         return $that->getJobFromUidInternal( $uid, $conn );
 535                                 },
 536                                 array( 'accept' => function ( $job ) {
 537                                         return is_object( $job );
 538                                 } )
 539                         );
 540                 } catch ( RedisException $e ) {
 541                         $this->throwRedisException( $this->server, $conn, $e );
 542                 }
 543         }
 544
 545         /**
 546          * @see JobQueue::getAllQueuedJobs()
 547          * @return Iterator
 548          */
 549         public function getAllDelayedJobs() {
 550                 $conn = $this->getConnection();
 551                 try {
 552                         $that = $this;
 553
 554                         return new MappedIterator( // delayed jobs
 555                                 $conn->zRange( $this->getQueueKey( 'z-delayed' ), 0, -1 ),
 556                                 function ( $uid ) use ( $that, $conn ) {
 557                                         return $that->getJobFromUidInternal( $uid, $conn );
 558                                 },
 559                                 array( 'accept' => function ( $job ) {
 560                                         return is_object( $job );
 561                                 } )
 562                         );
 563                 } catch ( RedisException $e ) {
 564                         $this->throwRedisException( $this->server, $conn, $e );
 565                 }
 566         }
 567
 568         public function getCoalesceLocationInternal() {
 569                 return "RedisServer:" . $this->server;
 570         }
 571
 572         protected function doGetSiblingQueuesWithJobs( array $types ) {
 573                 return array_keys( array_filter( $this->doGetSiblingQueueSizes( $types ) ) );
 574         }
 575
 576         protected function doGetSiblingQueueSizes( array $types ) {
 577                 $sizes = array(); // (type => size)
 578                 $types = array_values( $types ); // reindex
 579                 try {
 580                         $conn = $this->getConnection();
 581                         $conn->multi( Redis::PIPELINE );
 582                         foreach ( $types as $type ) {
 583                                 $conn->lSize( $this->getQueueKey( 'l-unclaimed', $type ) );
 584                         }
 585                         $res = $conn->exec();
 586                         if ( is_array( $res ) ) {
 587                                 foreach ( $res as $i => $size ) {
 588                                         $sizes[$types[$i]] = $size;
 589                                 }
 590                         }
 591                 } catch ( RedisException $e ) {
 592                         $this->throwRedisException( $this->server, $conn, $e );
 593                 }
 594
 595                 return $sizes;
 596         }
 597
 598         /**
 599          * This function should not be called outside JobQueueRedis
 600          *
 601          * @param $uid string
 602          * @param $conn RedisConnRef
 603          * @return Job|bool Returns false if the job does not exist
 604          * @throws MWException|JobQueueError
 605          */
 606         public function getJobFromUidInternal( $uid, RedisConnRef $conn ) {
 607                 try {
 608                         $data = $conn->hGet( $this->getQueueKey( 'h-data' ), $uid );
 609                         if ( $data === false ) {
 610                                 return false; // not found
 611                         }
 612                         $item = $this->unserialize( $conn->hGet( $this->getQueueKey( 'h-data' ), $uid ) );
 613                         if ( !is_array( $item ) ) { // this shouldn't happen
 614                                 throw new MWException( "Could not find job with ID '$uid'." );
 615                         }
 616                         $title = Title::makeTitle( $item['namespace'], $item['title'] );
 617                         $job = Job::factory( $item['type'], $title, $item['params'] );
 618                         $job->metadata['uuid'] = $item['uuid'];
 619
 620                         return $job;
 621                 } catch ( RedisException $e ) {
 622                         $this->throwRedisException( $this->server, $conn, $e );
 623                 }
 624         }
 625
 626         /**
 627          * Release any ready delayed jobs into the queue
 628          *
 629          * @return int Number of jobs released
 630          * @throws JobQueueError
 631          */
 632         public function releaseReadyDelayedJobs() {
 633                 $count = 0;
 634
 635                 $conn = $this->getConnection();
 636                 try {
 637                         static $script =
 638 <<<LUA
 639                         -- Get the list of ready delayed jobs, sorted by readiness
 640                         local ids = redis.call('zRangeByScore',KEYS[1],0,ARGV[1])
 641                         -- Migrate the jobs from the "delayed" set to the "unclaimed" list
 642                         for k,id in ipairs(ids) do
 643                                 redis.call('lPush',KEYS[2],id)
 644                                 redis.call('zRem',KEYS[1],id)
 645                         end
 646                         return #ids
 647 LUA;
 648                         $count += (int)$conn->luaEval( $script,
 649                                 array(
 650                                         $this->getQueueKey( 'z-delayed' ), // KEYS[1]
 651                                         $this->getQueueKey( 'l-unclaimed' ), // KEYS[2]
 652                                         time() // ARGV[1]; max "delay until" UNIX timestamp
 653                                 ),
 654                                 2 # first two arguments are keys
 655                         );
 656                 } catch ( RedisException $e ) {
 657                         $this->throwRedisException( $this->server, $conn, $e );
 658                 }
 659
 660                 return $count;
 661         }
 662
 663         /**
 664          * Recycle or destroy any jobs that have been claimed for too long
 665          *
 666          * @return int Number of jobs recycled/deleted
 667          * @throws MWException|JobQueueError
 668          */
 669         public function recycleAndDeleteStaleJobs() {
 670                 if ( $this->claimTTL <= 0 ) { // sanity
 671                         throw new MWException( "Cannot recycle jobs since acknowledgements are disabled." );
 672                 }
 673                 $count = 0;
 674                 // For each job item that can be retried, we need to add it back to the
 675                 // main queue and remove it from the list of currenty claimed job items.
 676                 // For those that cannot, they are marked as dead and kept around for
 677                 // investigation and manual job restoration but are eventually deleted.
 678                 $conn = $this->getConnection();
 679                 try {
 680                         $now = time();
 681                         static $script =
 682 <<<LUA
 683                         local released,abandoned,pruned = 0,0,0
 684                         -- Get all non-dead jobs that have an expired claim on them.
 685                         -- The score for each item is the last claim timestamp (UNIX).
 686                         local staleClaims = redis.call('zRangeByScore',KEYS[1],0,ARGV[1])
 687                         for k,id in ipairs(staleClaims) do
 688                                 local timestamp = redis.call('zScore',KEYS[1],id)
 689                                 local attempts = redis.call('hGet',KEYS[2],id)
 690                                 if attempts < ARGV[3] then
 691                                         -- Claim expired and retries left: re-enqueue the job
 692                                         redis.call('lPush',KEYS[3],id)
 693                                         redis.call('hIncrBy',KEYS[2],id,1)
 694                                         released = released + 1
 695                                 else
 696                                         -- Claim expired and no retries left: mark the job as dead
 697                                         redis.call('zAdd',KEYS[5],timestamp,id)
 698                                         abandoned = abandoned + 1
 699                                 end
 700                                 redis.call('zRem',KEYS[1],id)
 701                         end
 702                         -- Get all of the dead jobs that have been marked as dead for too long.
 703                         -- The score for each item is the last claim timestamp (UNIX).
 704                         local deadClaims = redis.call('zRangeByScore',KEYS[5],0,ARGV[2])
 705                         for k,id in ipairs(deadClaims) do
 706                                 -- Stale and out of retries: remove any traces of the job
 707                                 redis.call('zRem',KEYS[5],id)
 708                                 redis.call('hDel',KEYS[2],id)
 709                                 redis.call('hDel',KEYS[4],id)
 710                                 pruned = pruned + 1
 711                         end
 712                         return {released,abandoned,pruned}
 713 LUA;
 714                         $res = $conn->luaEval( $script,
 715                                 array(
 716                                         $this->getQueueKey( 'z-claimed' ), # KEYS[1]
 717                                         $this->getQueueKey( 'h-attempts' ), # KEYS[2]
 718                                         $this->getQueueKey( 'l-unclaimed' ), # KEYS[3]
 719                                         $this->getQueueKey( 'h-data' ), # KEYS[4]
 720                                         $this->getQueueKey( 'z-abandoned' ), # KEYS[5]
 721                                         $now - $this->claimTTL, # ARGV[1]
 722                                         $now - self::MAX_AGE_PRUNE, # ARGV[2]
 723                                         $this->maxTries # ARGV[3]
 724                                 ),
 725                                 5 # number of first argument(s) that are keys
 726                         );
 727                         if ( $res ) {
 728                                 list( $released, $abandoned, $pruned ) = $res;
 729                                 $count += $released + $pruned;
 730                                 JobQueue::incrStats( 'job-recycle', $this->type, $released );
 731                                 JobQueue::incrStats( 'job-abandon', $this->type, $abandoned );
 732                         }
 733                 } catch ( RedisException $e ) {
 734                         $this->throwRedisException( $this->server, $conn, $e );
 735                 }
 736
 737                 return $count;
 738         }
 739
 740         /**
 741          * @return array
 742          */
 743         protected function doGetPeriodicTasks() {
 744                 $tasks = array();
 745                 if ( $this->claimTTL > 0 ) {
 746                         $tasks['recycleAndDeleteStaleJobs'] = array(
 747                                 'callback' => array( $this, 'recycleAndDeleteStaleJobs' ),
 748                                 'period' => ceil( $this->claimTTL / 2 )
 749                         );
 750                 }
 751                 if ( $this->checkDelay ) {
 752                         $tasks['releaseReadyDelayedJobs'] = array(
 753                                 'callback' => array( $this, 'releaseReadyDelayedJobs' ),
 754                                 'period' => 300 // 5 minutes
 755                         );
 756                 }
 757
 758                 return $tasks;
 759         }
 760
 761         /**
 762          * @param Job $job
 763          * @return array
 764          */
 765         protected function getNewJobFields( Job $job ) {
 766                 return array(
 767                         // Fields that describe the nature of the job
 768                         'type' => $job->getType(),
 769                         'namespace' => $job->getTitle()->getNamespace(),
 770                         'title' => $job->getTitle()->getDBkey(),
 771                         'params' => $job->getParams(),
 772                         // Some jobs cannot run until a "release timestamp"
 773                         'rtimestamp' => $job->getReleaseTimestamp() ? : 0,
 774                         // Additional job metadata
 775                         'uuid' => UIDGenerator::newRawUUIDv4( UIDGenerator::QUICK_RAND ),
 776                         'sha1' => $job->ignoreDuplicates()
 777                                         ? wfBaseConvert( sha1( serialize( $job->getDeduplicationInfo() ) ), 16, 36, 31 )
 778                                         : '',
 779                         'timestamp' => time() // UNIX timestamp
 780                 );
 781         }
 782
 783         /**
 784          * @param $fields array
 785          * @return Job|bool
 786          */
 787         protected function getJobFromFields( array $fields ) {
 788                 $title = Title::makeTitleSafe( $fields['namespace'], $fields['title'] );
 789                 if ( $title ) {
 790                         $job = Job::factory( $fields['type'], $title, $fields['params'] );
 791                         $job->metadata['uuid'] = $fields['uuid'];
 792
 793                         return $job;
 794                 }
 795
 796                 return false;
 797         }
 798
 799         /**
 800          * @param array $fields
 801          * @return string Serialized and possibly compressed version of $fields
 802          */
 803         protected function serialize( array $fields ) {
 804                 $blob = serialize( $fields );
 805                 if ( $this->compression === 'gzip'
 806                         && strlen( $blob ) >= 1024
 807                         && function_exists( 'gzdeflate' )
 808                 ) {
 809                         $object = (object)array( 'blob' => gzdeflate( $blob ), 'enc' => 'gzip' );
 810                         $blobz = serialize( $object );
 811
 812                         return ( strlen( $blobz ) < strlen( $blob ) ) ? $blobz : $blob;
 813                 } else {
 814                         return $blob;
 815                 }
 816         }
 817
 818         /**
 819          * @param string $blob
 820          * @return array|bool Unserialized version of $blob or false
 821          */
 822         protected function unserialize( $blob ) {
 823                 $fields = unserialize( $blob );
 824                 if ( is_object( $fields ) ) {
 825                         if ( $fields->enc === 'gzip' && function_exists( 'gzinflate' ) ) {
 826                                 $fields = unserialize( gzinflate( $fields->blob ) );
 827                         } else {
 828                                 $fields = false;
 829                         }
 830                 }
 831
 832                 return is_array( $fields ) ? $fields : false;
 833         }
 834
 835         /**
 836          * Get a connection to the server that handles all sub-queues for this queue
 837          *
 838          * @return RedisConnRef
 839          * @throws JobQueueConnectionError
 840          */
 841         protected function getConnection() {
 842                 $conn = $this->redisPool->getConnection( $this->server );
 843                 if ( !$conn ) {
 844                         throw new JobQueueConnectionError( "Unable to connect to redis server." );
 845                 }
 846
 847                 return $conn;
 848         }
 849
 850         /**
 851          * @param $server string
 852          * @param $conn RedisConnRef
 853          * @param $e RedisException
 854          * @throws JobQueueError
 855          */
 856         protected function throwRedisException( $server, RedisConnRef $conn, $e ) {
 857                 $this->redisPool->handleException( $server, $conn, $e );
 858                 throw new JobQueueError( "Redis server error: {$e->getMessage()}\n" );
 859         }
 860
 861         /**
 862          * @param $prop string
 863          * @param $type string|null
 864          * @return string
 865          */
 866         private function getQueueKey( $prop, $type = null ) {
 867                 $type = is_string( $type ) ? $type : $this->type;
 868                 list( $db, $prefix ) = wfSplitWikiID( $this->wiki );
 869                 if ( strlen( $this->key ) ) { // namespaced queue (for testing)
 870                         return wfForeignMemcKey( $db, $prefix, 'jobqueue', $type, $this->key, $prop );
 871                 } else {
 872                         return wfForeignMemcKey( $db, $prefix, 'jobqueue', $type, $prop );
 873                 }
 874         }
 875
 876         /**
 877          * @param $key string
 878          * @return void
 879          */
 880         public function setTestingPrefix( $key ) {
 881                 $this->key = $key;
 882         }
 883 }