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