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