includes/jobqueue/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         /** @var string Compression method to use */
  66         protected $compression;
  67         /** @var bool */
  68         protected $daemonized;
  69
  70         const MAX_AGE_PRUNE = 604800; // integer; seconds a job can live once claimed (7 days)
  71
  72         /** @var string Key to prefix the queue keys with (used for testing) */
  73         protected $key;
  74
  75         /**
  76          * @params include:
  77          *   - redisConfig : An array of parameters to RedisConnectionPool::__construct().
  78          *                   Note that the serializer option is ignored as "none" is always used.
  79          *   - redisServer : A hostname/port combination or the absolute path of a UNIX socket.
  80          *                   If a hostname is specified but no port, the standard port number
  81          *                   6379 will be used. Required.
  82          *   - compression : The type of compression to use; one of (none,gzip).
  83          *   - daemonized  : Set to true if the redisJobRunnerService runs in the background.
  84          *                   This will disable job recycling/undelaying from the MediaWiki side
  85          *                   to avoid redundance and out-of-sync configuration.
  86          * @param array $params
  87          */
  88         public function __construct( array $params ) {
  89                 parent::__construct( $params );
  90                 $params['redisConfig']['serializer'] = 'none'; // make it easy to use Lua
  91                 $this->server = $params['redisServer'];
  92                 $this->compression = isset( $params['compression'] ) ? $params['compression'] : 'none';
  93                 $this->redisPool = RedisConnectionPool::singleton( $params['redisConfig'] );
  94                 $this->daemonized = !empty( $params['daemonized'] );
  95         }
  96
  97         protected function supportedOrders() {
  98                 return array( 'timestamp', 'fifo' );
  99         }
 100
 101         protected function optimalOrder() {
 102                 return 'fifo';
 103         }
 104
 105         protected function supportsDelayedJobs() {
 106                 return true;
 107         }
 108
 109         /**
 110          * @see JobQueue::doIsEmpty()
 111          * @return bool
 112          * @throws MWException
 113          */
 114         protected function doIsEmpty() {
 115                 return $this->doGetSize() == 0;
 116         }
 117
 118         /**
 119          * @see JobQueue::doGetSize()
 120          * @return int
 121          * @throws MWException
 122          */
 123         protected function doGetSize() {
 124                 $conn = $this->getConnection();
 125                 try {
 126                         return $conn->lSize( $this->getQueueKey( 'l-unclaimed' ) );
 127                 } catch ( RedisException $e ) {
 128                         $this->throwRedisException( $conn, $e );
 129                 }
 130         }
 131
 132         /**
 133          * @see JobQueue::doGetAcquiredCount()
 134          * @return int
 135          * @throws JobQueueError
 136          */
 137         protected function doGetAcquiredCount() {
 138                 if ( $this->claimTTL <= 0 ) {
 139                         return 0; // no acknowledgements
 140                 }
 141                 $conn = $this->getConnection();
 142                 try {
 143                         $conn->multi( Redis::PIPELINE );
 144                         $conn->zSize( $this->getQueueKey( 'z-claimed' ) );
 145                         $conn->zSize( $this->getQueueKey( 'z-abandoned' ) );
 146
 147                         return array_sum( $conn->exec() );
 148                 } catch ( RedisException $e ) {
 149                         $this->throwRedisException( $conn, $e );
 150                 }
 151         }
 152
 153         /**
 154          * @see JobQueue::doGetDelayedCount()
 155          * @return int
 156          * @throws JobQueueError
 157          */
 158         protected function doGetDelayedCount() {
 159                 if ( !$this->checkDelay ) {
 160                         return 0; // no delayed jobs
 161                 }
 162                 $conn = $this->getConnection();
 163                 try {
 164                         return $conn->zSize( $this->getQueueKey( 'z-delayed' ) );
 165                 } catch ( RedisException $e ) {
 166                         $this->throwRedisException( $conn, $e );
 167                 }
 168         }
 169
 170         /**
 171          * @see JobQueue::doGetAbandonedCount()
 172          * @return int
 173          * @throws JobQueueError
 174          */
 175         protected function doGetAbandonedCount() {
 176                 if ( $this->claimTTL <= 0 ) {
 177                         return 0; // no acknowledgements
 178                 }
 179                 $conn = $this->getConnection();
 180                 try {
 181                         return $conn->zSize( $this->getQueueKey( 'z-abandoned' ) );
 182                 } catch ( RedisException $e ) {
 183                         $this->throwRedisException( $conn, $e );
 184                 }
 185         }
 186
 187         /**
 188          * @see JobQueue::doBatchPush()
 189          * @param array $jobs
 190          * @param int $flags
 191          * @return void
 192          * @throws JobQueueError
 193          */
 194         protected function doBatchPush( array $jobs, $flags ) {
 195                 // Convert the jobs into field maps (de-duplicated against each other)
 196                 $items = array(); // (job ID => job fields map)
 197                 foreach ( $jobs as $job ) {
 198                         $item = $this->getNewJobFields( $job );
 199                         if ( strlen( $item['sha1'] ) ) { // hash identifier => de-duplicate
 200                                 $items[$item['sha1']] = $item;
 201                         } else {
 202                                 $items[$item['uuid']] = $item;
 203                         }
 204                 }
 205
 206                 if ( !count( $items ) ) {
 207                         return; // nothing to do
 208                 }
 209
 210                 $conn = $this->getConnection();
 211                 try {
 212                         // Actually push the non-duplicate jobs into the queue...
 213                         if ( $flags & self::QOS_ATOMIC ) {
 214                                 $batches = array( $items ); // all or nothing
 215                         } else {
 216                                 $batches = array_chunk( $items, 500 ); // avoid tying up the server
 217                         }
 218                         $failed = 0;
 219                         $pushed = 0;
 220                         foreach ( $batches as $itemBatch ) {
 221                                 $added = $this->pushBlobs( $conn, $itemBatch );
 222                                 if ( is_int( $added ) ) {
 223                                         $pushed += $added;
 224                                 } else {
 225                                         $failed += count( $itemBatch );
 226                                 }
 227                         }
 228                         if ( $failed > 0 ) {
 229                                 wfDebugLog( 'JobQueueRedis', "Could not insert {$failed} {$this->type} job(s)." );
 230
 231                                 throw new RedisException( "Could not insert {$failed} {$this->type} job(s)." );
 232                         }
 233                         JobQueue::incrStats( 'job-insert', $this->type, count( $items ), $this->wiki );
 234                         JobQueue::incrStats( 'job-insert-duplicate', $this->type,
 235                                 count( $items ) - $failed - $pushed, $this->wiki );
 236                 } catch ( RedisException $e ) {
 237                         $this->throwRedisException( $conn, $e );
 238                 }
 239         }
 240
 241         /**
 242          * @param RedisConnRef $conn
 243          * @param array $items List of results from JobQueueRedis::getNewJobFields()
 244          * @return int Number of jobs inserted (duplicates are ignored)
 245          * @throws RedisException
 246          */
 247         protected function pushBlobs( RedisConnRef $conn, array $items ) {
 248                 $args = array(); // ([id, sha1, rtime, blob [, id, sha1, rtime, blob ... ] ] )
 249                 foreach ( $items as $item ) {
 250                         $args[] = (string)$item['uuid'];
 251                         $args[] = (string)$item['sha1'];
 252                         $args[] = (string)$item['rtimestamp'];
 253                         $args[] = (string)$this->serialize( $item );
 254                 }
 255                 static $script =
 256 <<<LUA
 257                 local kUnclaimed, kSha1ById, kIdBySha1, kDelayed, kData = unpack(KEYS)
 258                 if #ARGV % 4 ~= 0 then return redis.error_reply('Unmatched arguments') end
 259                 local pushed = 0
 260                 for i = 1,#ARGV,4 do
 261                         local id,sha1,rtimestamp,blob = ARGV[i],ARGV[i+1],ARGV[i+2],ARGV[i+3]
 262                         if sha1 == '' or redis.call('hExists',kIdBySha1,sha1) == 0 then
 263                                 if 1*rtimestamp > 0 then
 264                                         -- Insert into delayed queue (release time as score)
 265                                         redis.call('zAdd',kDelayed,rtimestamp,id)
 266                                 else
 267                                         -- Insert into unclaimed queue
 268                                         redis.call('lPush',kUnclaimed,id)
 269                                 end
 270                                 if sha1 ~= '' then
 271                                         redis.call('hSet',kSha1ById,id,sha1)
 272                                         redis.call('hSet',kIdBySha1,sha1,id)
 273                                 end
 274                                 redis.call('hSet',kData,id,blob)
 275                                 pushed = pushed + 1
 276                         end
 277                 end
 278                 return pushed
 279 LUA;
 280                 return $conn->luaEval( $script,
 281                         array_merge(
 282                                 array(
 283                                         $this->getQueueKey( 'l-unclaimed' ), # KEYS[1]
 284                                         $this->getQueueKey( 'h-sha1ById' ), # KEYS[2]
 285                                         $this->getQueueKey( 'h-idBySha1' ), # KEYS[3]
 286                                         $this->getQueueKey( 'z-delayed' ), # KEYS[4]
 287                                         $this->getQueueKey( 'h-data' ), # KEYS[5]
 288                                 ),
 289                                 $args
 290                         ),
 291                         5 # number of first argument(s) that are keys
 292                 );
 293         }
 294
 295         /**
 296          * @see JobQueue::doPop()
 297          * @return Job|bool
 298          * @throws JobQueueError
 299          */
 300         protected function doPop() {
 301                 $job = false;
 302
 303                 // Push ready delayed jobs into the queue every 10 jobs to spread the load.
 304                 // This is also done as a periodic task, but we don't want too much done at once.
 305                 if ( $this->checkDelay && mt_rand( 0, 9 ) == 0 ) {
 306                         $this->recyclePruneAndUndelayJobs();
 307                 }
 308
 309                 $conn = $this->getConnection();
 310                 try {
 311                         do {
 312                                 if ( $this->claimTTL > 0 ) {
 313                                         // Keep the claimed job list down for high-traffic queues
 314                                         if ( mt_rand( 0, 99 ) == 0 ) {
 315                                                 $this->recyclePruneAndUndelayJobs();
 316                                         }
 317                                         $blob = $this->popAndAcquireBlob( $conn );
 318                                 } else {
 319                                         $blob = $this->popAndDeleteBlob( $conn );
 320                                 }
 321                                 if ( !is_string( $blob ) ) {
 322                                         break; // no jobs; nothing to do
 323                                 }
 324
 325                                 JobQueue::incrStats( 'job-pop', $this->type, 1, $this->wiki );
 326                                 $item = $this->unserialize( $blob );
 327                                 if ( $item === false ) {
 328                                         wfDebugLog( 'JobQueueRedis', "Could not unserialize {$this->type} job." );
 329                                         continue;
 330                                 }
 331
 332                                 // If $item is invalid, recyclePruneAndUndelayJobs() will cleanup as needed
 333                                 $job = $this->getJobFromFields( $item ); // may be false
 334                         } while ( !$job ); // job may be false if invalid
 335                 } catch ( RedisException $e ) {
 336                         $this->throwRedisException( $conn, $e );
 337                 }
 338
 339                 return $job;
 340         }
 341
 342         /**
 343          * @param RedisConnRef $conn
 344          * @return array Serialized string or false
 345          * @throws RedisException
 346          */
 347         protected function popAndDeleteBlob( RedisConnRef $conn ) {
 348                 static $script =
 349 <<<LUA
 350                 local kUnclaimed, kSha1ById, kIdBySha1, kData = unpack(KEYS)
 351                 -- Pop an item off the queue
 352                 local id = redis.call('rpop',kUnclaimed)
 353                 if not id then return false end
 354                 -- Get the job data and remove it
 355                 local item = redis.call('hGet',kData,id)
 356                 redis.call('hDel',kData,id)
 357                 -- Allow new duplicates of this job
 358                 local sha1 = redis.call('hGet',kSha1ById,id)
 359                 if sha1 then redis.call('hDel',kIdBySha1,sha1) end
 360                 redis.call('hDel',kSha1ById,id)
 361                 -- Return the job data
 362                 return item
 363 LUA;
 364                 return $conn->luaEval( $script,
 365                         array(
 366                                 $this->getQueueKey( 'l-unclaimed' ), # KEYS[1]
 367                                 $this->getQueueKey( 'h-sha1ById' ), # KEYS[2]
 368                                 $this->getQueueKey( 'h-idBySha1' ), # KEYS[3]
 369                                 $this->getQueueKey( 'h-data' ), # KEYS[4]
 370                         ),
 371                         4 # number of first argument(s) that are keys
 372                 );
 373         }
 374
 375         /**
 376          * @param RedisConnRef $conn
 377          * @return array Serialized string or false
 378          * @throws RedisException
 379          */
 380         protected function popAndAcquireBlob( RedisConnRef $conn ) {
 381                 static $script =
 382 <<<LUA
 383                 local kUnclaimed, kSha1ById, kIdBySha1, kClaimed, kAttempts, kData = unpack(KEYS)
 384                 -- Pop an item off the queue
 385                 local id = redis.call('rPop',kUnclaimed)
 386                 if not id then return false end
 387                 -- Allow new duplicates of this job
 388                 local sha1 = redis.call('hGet',kSha1ById,id)
 389                 if sha1 then redis.call('hDel',kIdBySha1,sha1) end
 390                 redis.call('hDel',kSha1ById,id)
 391                 -- Mark the jobs as claimed and return it
 392                 redis.call('zAdd',kClaimed,ARGV[1],id)
 393                 redis.call('hIncrBy',kAttempts,id,1)
 394                 return redis.call('hGet',kData,id)
 395 LUA;
 396                 return $conn->luaEval( $script,
 397                         array(
 398                                 $this->getQueueKey( 'l-unclaimed' ), # KEYS[1]
 399                                 $this->getQueueKey( 'h-sha1ById' ), # KEYS[2]
 400                                 $this->getQueueKey( 'h-idBySha1' ), # KEYS[3]
 401                                 $this->getQueueKey( 'z-claimed' ), # KEYS[4]
 402                                 $this->getQueueKey( 'h-attempts' ), # KEYS[5]
 403                                 $this->getQueueKey( 'h-data' ), # KEYS[6]
 404                                 time(), # ARGV[1] (injected to be replication-safe)
 405                         ),
 406                         6 # number of first argument(s) that are keys
 407                 );
 408         }
 409
 410         /**
 411          * @see JobQueue::doAck()
 412          * @param Job $job
 413          * @return Job|bool
 414          * @throws MWException|JobQueueError
 415          */
 416         protected function doAck( Job $job ) {
 417                 if ( !isset( $job->metadata['uuid'] ) ) {
 418                         throw new MWException( "Job of type '{$job->getType()}' has no UUID." );
 419                 }
 420                 if ( $this->claimTTL > 0 ) {
 421                         $conn = $this->getConnection();
 422                         try {
 423                                 static $script =
 424 <<<LUA
 425                                 local kClaimed, kAttempts, kData = unpack(KEYS)
 426                                 -- Unmark the job as claimed
 427                                 redis.call('zRem',kClaimed,ARGV[1])
 428                                 redis.call('hDel',kAttempts,ARGV[1])
 429                                 -- Delete the job data itself
 430                                 return redis.call('hDel',kData,ARGV[1])
 431 LUA;
 432                                 $res = $conn->luaEval( $script,
 433                                         array(
 434                                                 $this->getQueueKey( 'z-claimed' ), # KEYS[1]
 435                                                 $this->getQueueKey( 'h-attempts' ), # KEYS[2]
 436                                                 $this->getQueueKey( 'h-data' ), # KEYS[3]
 437                                                 $job->metadata['uuid'] # ARGV[1]
 438                                         ),
 439                                         3 # number of first argument(s) that are keys
 440                                 );
 441
 442                                 if ( !$res ) {
 443                                         wfDebugLog( 'JobQueueRedis', "Could not acknowledge {$this->type} job." );
 444
 445                                         return false;
 446                                 }
 447                         } catch ( RedisException $e ) {
 448                                 $this->throwRedisException( $conn, $e );
 449                         }
 450                 }
 451
 452                 return true;
 453         }
 454
 455         /**
 456          * @see JobQueue::doDeduplicateRootJob()
 457          * @param Job $job
 458          * @return bool
 459          * @throws MWException|JobQueueError
 460          */
 461         protected function doDeduplicateRootJob( Job $job ) {
 462                 if ( !$job->hasRootJobParams() ) {
 463                         throw new MWException( "Cannot register root job; missing parameters." );
 464                 }
 465                 $params = $job->getRootJobParams();
 466
 467                 $key = $this->getRootJobCacheKey( $params['rootJobSignature'] );
 468
 469                 $conn = $this->getConnection();
 470                 try {
 471                         $timestamp = $conn->get( $key ); // current last timestamp of this job
 472                         if ( $timestamp && $timestamp >= $params['rootJobTimestamp'] ) {
 473                                 return true; // a newer version of this root job was enqueued
 474                         }
 475
 476                         // Update the timestamp of the last root job started at the location...
 477                         return $conn->set( $key, $params['rootJobTimestamp'], self::ROOTJOB_TTL ); // 2 weeks
 478                 } catch ( RedisException $e ) {
 479                         $this->throwRedisException( $conn, $e );
 480                 }
 481         }
 482
 483         /**
 484          * @see JobQueue::doIsRootJobOldDuplicate()
 485          * @param Job $job
 486          * @return bool
 487          * @throws JobQueueError
 488          */
 489         protected function doIsRootJobOldDuplicate( Job $job ) {
 490                 if ( !$job->hasRootJobParams() ) {
 491                         return false; // job has no de-deplication info
 492                 }
 493                 $params = $job->getRootJobParams();
 494
 495                 $conn = $this->getConnection();
 496                 try {
 497                         // Get the last time this root job was enqueued
 498                         $timestamp = $conn->get( $this->getRootJobCacheKey( $params['rootJobSignature'] ) );
 499                 } catch ( RedisException $e ) {
 500                         $this->throwRedisException( $conn, $e );
 501                 }
 502
 503                 // Check if a new root job was started at the location after this one's...
 504                 return ( $timestamp && $timestamp > $params['rootJobTimestamp'] );
 505         }
 506
 507         /**
 508          * @see JobQueue::doDelete()
 509          * @return bool
 510          * @throws JobQueueError
 511          */
 512         protected function doDelete() {
 513                 static $props = array( 'l-unclaimed', 'z-claimed', 'z-abandoned',
 514                         'z-delayed', 'h-idBySha1', 'h-sha1ById', 'h-attempts', 'h-data' );
 515
 516                 $conn = $this->getConnection();
 517                 try {
 518                         $keys = array();
 519                         foreach ( $props as $prop ) {
 520                                 $keys[] = $this->getQueueKey( $prop );
 521                         }
 522
 523                         return ( $conn->delete( $keys ) !== false );
 524                 } catch ( RedisException $e ) {
 525                         $this->throwRedisException( $conn, $e );
 526                 }
 527         }
 528
 529         /**
 530          * @see JobQueue::getAllQueuedJobs()
 531          * @return Iterator
 532          */
 533         public function getAllQueuedJobs() {
 534                 $conn = $this->getConnection();
 535                 try {
 536                         $that = $this;
 537
 538                         return new MappedIterator(
 539                                 $conn->lRange( $this->getQueueKey( 'l-unclaimed' ), 0, -1 ),
 540                                 function ( $uid ) use ( $that, $conn ) {
 541                                         return $that->getJobFromUidInternal( $uid, $conn );
 542                                 },
 543                                 array( 'accept' => function ( $job ) {
 544                                         return is_object( $job );
 545                                 } )
 546                         );
 547                 } catch ( RedisException $e ) {
 548                         $this->throwRedisException( $conn, $e );
 549                 }
 550         }
 551
 552         /**
 553          * @see JobQueue::getAllQueuedJobs()
 554          * @return Iterator
 555          */
 556         public function getAllDelayedJobs() {
 557                 $conn = $this->getConnection();
 558                 try {
 559                         $that = $this;
 560
 561                         return new MappedIterator( // delayed jobs
 562                                 $conn->zRange( $this->getQueueKey( 'z-delayed' ), 0, -1 ),
 563                                 function ( $uid ) use ( $that, $conn ) {
 564                                         return $that->getJobFromUidInternal( $uid, $conn );
 565                                 },
 566                                 array( 'accept' => function ( $job ) {
 567                                         return is_object( $job );
 568                                 } )
 569                         );
 570                 } catch ( RedisException $e ) {
 571                         $this->throwRedisException( $conn, $e );
 572                 }
 573         }
 574
 575         public function getCoalesceLocationInternal() {
 576                 return "RedisServer:" . $this->server;
 577         }
 578
 579         protected function doGetSiblingQueuesWithJobs( array $types ) {
 580                 return array_keys( array_filter( $this->doGetSiblingQueueSizes( $types ) ) );
 581         }
 582
 583         protected function doGetSiblingQueueSizes( array $types ) {
 584                 $sizes = array(); // (type => size)
 585                 $types = array_values( $types ); // reindex
 586                 $conn = $this->getConnection();
 587                 try {
 588                         $conn->multi( Redis::PIPELINE );
 589                         foreach ( $types as $type ) {
 590                                 $conn->lSize( $this->getQueueKey( 'l-unclaimed', $type ) );
 591                         }
 592                         $res = $conn->exec();
 593                         if ( is_array( $res ) ) {
 594                                 foreach ( $res as $i => $size ) {
 595                                         $sizes[$types[$i]] = $size;
 596                                 }
 597                         }
 598                 } catch ( RedisException $e ) {
 599                         $this->throwRedisException( $conn, $e );
 600                 }
 601
 602                 return $sizes;
 603         }
 604
 605         /**
 606          * This function should not be called outside JobQueueRedis
 607          *
 608          * @param string $uid
 609          * @param RedisConnRef $conn
 610          * @return Job|bool Returns false if the job does not exist
 611          * @throws MWException|JobQueueError
 612          */
 613         public function getJobFromUidInternal( $uid, RedisConnRef $conn ) {
 614                 try {
 615                         $data = $conn->hGet( $this->getQueueKey( 'h-data' ), $uid );
 616                         if ( $data === false ) {
 617                                 return false; // not found
 618                         }
 619                         $item = $this->unserialize( $conn->hGet( $this->getQueueKey( 'h-data' ), $uid ) );
 620                         if ( !is_array( $item ) ) { // this shouldn't happen
 621                                 throw new MWException( "Could not find job with ID '$uid'." );
 622                         }
 623                         $title = Title::makeTitle( $item['namespace'], $item['title'] );
 624                         $job = Job::factory( $item['type'], $title, $item['params'] );
 625                         $job->metadata['uuid'] = $item['uuid'];
 626
 627                         return $job;
 628                 } catch ( RedisException $e ) {
 629                         $this->throwRedisException( $conn, $e );
 630                 }
 631         }
 632
 633         /**
 634          * Recycle or destroy any jobs that have been claimed for too long
 635          * and release any ready delayed jobs into the queue
 636          *
 637          * @return int Number of jobs recycled/deleted/undelayed
 638          * @throws MWException|JobQueueError
 639          */
 640         public function recyclePruneAndUndelayJobs() {
 641                 $count = 0;
 642                 // For each job item that can be retried, we need to add it back to the
 643                 // main queue and remove it from the list of currenty claimed job items.
 644                 // For those that cannot, they are marked as dead and kept around for
 645                 // investigation and manual job restoration but are eventually deleted.
 646                 $conn = $this->getConnection();
 647                 try {
 648                         $now = time();
 649                         static $script =
 650 <<<LUA
 651                         local kClaimed, kAttempts, kUnclaimed, kData, kAbandoned, kDelayed = unpack(KEYS)
 652                         local released,abandoned,pruned,undelayed = 0,0,0,0
 653                         -- Get all non-dead jobs that have an expired claim on them.
 654                         -- The score for each item is the last claim timestamp (UNIX).
 655                         local staleClaims = redis.call('zRangeByScore',kClaimed,0,ARGV[1])
 656                         for k,id in ipairs(staleClaims) do
 657                                 local timestamp = redis.call('zScore',kClaimed,id)
 658                                 local attempts = redis.call('hGet',kAttempts,id)
 659                                 if attempts < ARGV[3] then
 660                                         -- Claim expired and retries left: re-enqueue the job
 661                                         redis.call('lPush',kUnclaimed,id)
 662                                         redis.call('hIncrBy',kAttempts,id,1)
 663                                         released = released + 1
 664                                 else
 665                                         -- Claim expired and no retries left: mark the job as dead
 666                                         redis.call('zAdd',kAbandoned,timestamp,id)
 667                                         abandoned = abandoned + 1
 668                                 end
 669                                 redis.call('zRem',kClaimed,id)
 670                         end
 671                         -- Get all of the dead jobs that have been marked as dead for too long.
 672                         -- The score for each item is the last claim timestamp (UNIX).
 673                         local deadClaims = redis.call('zRangeByScore',kAbandoned,0,ARGV[2])
 674                         for k,id in ipairs(deadClaims) do
 675                                 -- Stale and out of retries: remove any traces of the job
 676                                 redis.call('zRem',kAbandoned,id)
 677                                 redis.call('hDel',kAttempts,id)
 678                                 redis.call('hDel',kData,id)
 679                                 pruned = pruned + 1
 680                         end
 681                         -- Get the list of ready delayed jobs, sorted by readiness (UNIX timestamp)
 682                         local ids = redis.call('zRangeByScore',kDelayed,0,ARGV[4])
 683                         -- Migrate the jobs from the "delayed" set to the "unclaimed" list
 684                         for k,id in ipairs(ids) do
 685                                 redis.call('lPush',kUnclaimed,id)
 686                                 redis.call('zRem',kDelayed,id)
 687                         end
 688                         undelayed = #ids
 689                         return {released,abandoned,pruned,undelayed}
 690 LUA;
 691                         $res = $conn->luaEval( $script,
 692                                 array(
 693                                         $this->getQueueKey( 'z-claimed' ), # KEYS[1]
 694                                         $this->getQueueKey( 'h-attempts' ), # KEYS[2]
 695                                         $this->getQueueKey( 'l-unclaimed' ), # KEYS[3]
 696                                         $this->getQueueKey( 'h-data' ), # KEYS[4]
 697                                         $this->getQueueKey( 'z-abandoned' ), # KEYS[5]
 698                                         $this->getQueueKey( 'z-delayed' ), # KEYS[6]
 699                                         $now - $this->claimTTL, # ARGV[1]
 700                                         $now - self::MAX_AGE_PRUNE, # ARGV[2]
 701                                         $this->maxTries, # ARGV[3]
 702                                         $now # ARGV[4]
 703                                 ),
 704                                 6 # number of first argument(s) that are keys
 705                         );
 706                         if ( $res ) {
 707                                 list( $released, $abandoned, $pruned, $undelayed ) = $res;
 708                                 $count += $released + $pruned + $undelayed;
 709                                 JobQueue::incrStats( 'job-recycle', $this->type, $released, $this->wiki );
 710                                 JobQueue::incrStats( 'job-abandon', $this->type, $abandoned, $this->wiki );
 711                                 JobQueue::incrStats( 'job-undelay', $this->type, $undelayed, $this->wiki );
 712                         }
 713                 } catch ( RedisException $e ) {
 714                         $this->throwRedisException( $conn, $e );
 715                 }
 716
 717                 return $count;
 718         }
 719
 720         /**
 721          * @return array
 722          */
 723         protected function doGetPeriodicTasks() {
 724                 if ( $this->daemonized ) {
 725                         return array(); // managed in the runner loop
 726                 }
 727                 $periods = array( 3600 ); // standard cleanup (useful on config change)
 728                 if ( $this->claimTTL > 0 ) {
 729                         $periods[] = ceil( $this->claimTTL / 2 ); // avoid bad timing
 730                 }
 731                 if ( $this->checkDelay ) {
 732                         $periods[] = 300; // 5 minutes
 733                 }
 734                 $period = min( $periods );
 735                 $period = max( $period, 30 ); // sanity
 736
 737                 return array(
 738                         'recyclePruneAndUndelayJobs' => array(
 739                                 'callback' => array( $this, 'recyclePruneAndUndelayJobs' ),
 740                                 'period'   => $period,
 741                         )
 742                 );
 743         }
 744
 745         /**
 746          * @param IJobSpecification $job
 747          * @return array
 748          */
 749         protected function getNewJobFields( IJobSpecification $job ) {
 750                 return array(
 751                         // Fields that describe the nature of the job
 752                         'type' => $job->getType(),
 753                         'namespace' => $job->getTitle()->getNamespace(),
 754                         'title' => $job->getTitle()->getDBkey(),
 755                         'params' => $job->getParams(),
 756                         // Some jobs cannot run until a "release timestamp"
 757                         'rtimestamp' => $job->getReleaseTimestamp() ?: 0,
 758                         // Additional job metadata
 759                         'uuid' => UIDGenerator::newRawUUIDv4( UIDGenerator::QUICK_RAND ),
 760                         'sha1' => $job->ignoreDuplicates()
 761                                 ? wfBaseConvert( sha1( serialize( $job->getDeduplicationInfo() ) ), 16, 36, 31 )
 762                                 : '',
 763                         'timestamp' => time() // UNIX timestamp
 764                 );
 765         }
 766
 767         /**
 768          * @param array $fields
 769          * @return Job|bool
 770          */
 771         protected function getJobFromFields( array $fields ) {
 772                 $title = Title::makeTitleSafe( $fields['namespace'], $fields['title'] );
 773                 if ( $title ) {
 774                         $job = Job::factory( $fields['type'], $title, $fields['params'] );
 775                         $job->metadata['uuid'] = $fields['uuid'];
 776
 777                         return $job;
 778                 }
 779
 780                 return false;
 781         }
 782
 783         /**
 784          * @param array $fields
 785          * @return string Serialized and possibly compressed version of $fields
 786          */
 787         protected function serialize( array $fields ) {
 788                 $blob = serialize( $fields );
 789                 if ( $this->compression === 'gzip'
 790                         && strlen( $blob ) >= 1024
 791                         && function_exists( 'gzdeflate' )
 792                 ) {
 793                         $object = (object)array( 'blob' => gzdeflate( $blob ), 'enc' => 'gzip' );
 794                         $blobz = serialize( $object );
 795
 796                         return ( strlen( $blobz ) < strlen( $blob ) ) ? $blobz : $blob;
 797                 } else {
 798                         return $blob;
 799                 }
 800         }
 801
 802         /**
 803          * @param string $blob
 804          * @return array|bool Unserialized version of $blob or false
 805          */
 806         protected function unserialize( $blob ) {
 807                 $fields = unserialize( $blob );
 808                 if ( is_object( $fields ) ) {
 809                         if ( $fields->enc === 'gzip' && function_exists( 'gzinflate' ) ) {
 810                                 $fields = unserialize( gzinflate( $fields->blob ) );
 811                         } else {
 812                                 $fields = false;
 813                         }
 814                 }
 815
 816                 return is_array( $fields ) ? $fields : false;
 817         }
 818
 819         /**
 820          * Get a connection to the server that handles all sub-queues for this queue
 821          *
 822          * @return RedisConnRef
 823          * @throws JobQueueConnectionError
 824          */
 825         protected function getConnection() {
 826                 $conn = $this->redisPool->getConnection( $this->server );
 827                 if ( !$conn ) {
 828                         throw new JobQueueConnectionError( "Unable to connect to redis server." );
 829                 }
 830
 831                 return $conn;
 832         }
 833
 834         /**
 835          * @param RedisConnRef $conn
 836          * @param RedisException $e
 837          * @throws JobQueueError
 838          */
 839         protected function throwRedisException( RedisConnRef $conn, $e ) {
 840                 $this->redisPool->handleError( $conn, $e );
 841                 throw new JobQueueError( "Redis server error: {$e->getMessage()}\n" );
 842         }
 843
 844         /**
 845          * @param string $prop
 846          * @param string|null $type
 847          * @return string
 848          */
 849         private function getQueueKey( $prop, $type = null ) {
 850                 $type = is_string( $type ) ? $type : $this->type;
 851                 list( $db, $prefix ) = wfSplitWikiID( $this->wiki );
 852                 if ( strlen( $this->key ) ) { // namespaced queue (for testing)
 853                         return wfForeignMemcKey( $db, $prefix, 'jobqueue', $type, $this->key, $prop );
 854                 } else {
 855                         return wfForeignMemcKey( $db, $prefix, 'jobqueue', $type, $prop );
 856                 }
 857         }
 858
 859         /**
 860          * @param string $key
 861          * @return void
 862          */
 863         public function setTestingPrefix( $key ) {
 864                 $this->key = $key;
 865         }
 866 }