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