includes/job/Job.php

   1 <?php
   2 /**
   3  * Job queue base 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  * @defgroup JobQueue JobQueue
  22  */
  23
  24 /**
  25  * Class to both describe a background job and handle jobs.
  26  * The queue aspects of this class are now deprecated.
  27  *
  28  * @ingroup JobQueue
  29  */
  30 abstract class Job {
  31         /**
  32          * @var Title
  33          */
  34         var $title;
  35
  36         var $command,
  37                 $params,
  38                 $id,
  39                 $removeDuplicates,
  40                 $error;
  41
  42         /** @var Array Additional queue metadata */
  43         public $metadata = array();
  44
  45         /*-------------------------------------------------------------------------
  46          * Abstract functions
  47          *------------------------------------------------------------------------*/
  48
  49         /**
  50          * Run the job
  51          * @return boolean success
  52          */
  53         abstract public function run();
  54
  55         /*-------------------------------------------------------------------------
  56          * Static functions
  57          *------------------------------------------------------------------------*/
  58
  59         /**
  60          * Create the appropriate object to handle a specific job
  61          *
  62          * @param string $command Job command
  63          * @param $title Title: Associated title
  64          * @param array|bool $params Job parameters
  65          * @param int $id Job identifier
  66          * @throws MWException
  67          * @return Job
  68          */
  69         public static function factory( $command, Title $title, $params = false, $id = 0 ) {
  70                 global $wgJobClasses;
  71                 if( isset( $wgJobClasses[$command] ) ) {
  72                         $class = $wgJobClasses[$command];
  73                         return new $class( $title, $params, $id );
  74                 }
  75                 throw new MWException( "Invalid job command `{$command}`" );
  76         }
  77
  78         /**
  79          * Batch-insert a group of jobs into the queue.
  80          * This will be wrapped in a transaction with a forced commit.
  81          *
  82          * This may add duplicate at insert time, but they will be
  83          * removed later on, when the first one is popped.
  84          *
  85          * @param array $jobs of Job objects
  86          * @return bool
  87          * @deprecated 1.21
  88          */
  89         public static function batchInsert( $jobs ) {
  90                 return JobQueueGroup::singleton()->push( $jobs );
  91         }
  92
  93         /**
  94          * Insert a group of jobs into the queue.
  95          *
  96          * Same as batchInsert() but does not commit and can thus
  97          * be rolled-back as part of a larger transaction. However,
  98          * large batches of jobs can cause slave lag.
  99          *
 100          * @param array $jobs of Job objects
 101          * @return bool
 102          * @deprecated 1.21
 103          */
 104         public static function safeBatchInsert( $jobs ) {
 105                 return JobQueueGroup::singleton()->push( $jobs, JobQueue::QOS_ATOMIC );
 106         }
 107
 108         /**
 109          * Pop a job of a certain type.  This tries less hard than pop() to
 110          * actually find a job; it may be adversely affected by concurrent job
 111          * runners.
 112          *
 113          * @param $type string
 114          * @return Job|bool Returns false if there are no jobs
 115          * @deprecated 1.21
 116          */
 117         public static function pop_type( $type ) {
 118                 return JobQueueGroup::singleton()->get( $type )->pop();
 119         }
 120
 121         /**
 122          * Pop a job off the front of the queue.
 123          * This is subject to $wgJobTypesExcludedFromDefaultQueue.
 124          *
 125          * @return Job or false if there's no jobs
 126          * @deprecated 1.21
 127          */
 128         public static function pop() {
 129                 return JobQueueGroup::singleton()->pop();
 130         }
 131
 132         /*-------------------------------------------------------------------------
 133          * Non-static functions
 134          *------------------------------------------------------------------------*/
 135
 136         /**
 137          * @param $command
 138          * @param $title
 139          * @param $params array|bool
 140          * @param $id int
 141          */
 142         public function __construct( $command, $title, $params = false, $id = 0 ) {
 143                 $this->command = $command;
 144                 $this->title = $title;
 145                 $this->params = $params;
 146                 $this->id = $id;
 147
 148                 $this->removeDuplicates = false; // expensive jobs may set this to true
 149         }
 150
 151         /**
 152          * @return integer May be 0 for jobs stored outside the DB
 153          */
 154         public function getId() {
 155                 return $this->id;
 156         }
 157
 158         /**
 159          * @return string
 160          */
 161         public function getType() {
 162                 return $this->command;
 163         }
 164
 165         /**
 166          * @return Title
 167          */
 168         public function getTitle() {
 169                 return $this->title;
 170         }
 171
 172         /**
 173          * @return array
 174          */
 175         public function getParams() {
 176                 return $this->params;
 177         }
 178
 179         /**
 180          * @return integer|null UNIX timestamp to delay running this job until, otherwise null
 181          * @since 1.22
 182          */
 183         public function getReleaseTimestamp() {
 184                 return isset( $this->params['jobReleaseTimestamp'] )
 185                         ? wfTimestampOrNull( TS_UNIX, $this->params['jobReleaseTimestamp'] )
 186                         : null;
 187         }
 188
 189         /**
 190          * @return bool Whether only one of each identical set of jobs should be run
 191          */
 192         public function ignoreDuplicates() {
 193                 return $this->removeDuplicates;
 194         }
 195
 196         /**
 197          * @return bool Whether this job can be retried on failure by job runners
 198          * @since 1.21
 199          */
 200         public function allowRetries() {
 201                 return true;
 202         }
 203
 204         /**
 205          * Subclasses may need to override this to make duplication detection work.
 206          * The resulting map conveys everything that makes the job unique. This is
 207          * only checked if ignoreDuplicates() returns true, meaning that duplicate
 208          * jobs are supposed to be ignored.
 209          *
 210          * @return Array Map of key/values
 211          * @since 1.21
 212          */
 213         public function getDeduplicationInfo() {
 214                 $info = array(
 215                         'type'      => $this->getType(),
 216                         'namespace' => $this->getTitle()->getNamespace(),
 217                         'title'     => $this->getTitle()->getDBkey(),
 218                         'params'    => $this->getParams()
 219                 );
 220                 if ( is_array( $info['params'] ) ) {
 221                         // Identical jobs with different "root" jobs should count as duplicates
 222                         unset( $info['params']['rootJobSignature'] );
 223                         unset( $info['params']['rootJobTimestamp'] );
 224                         // Likewise for jobs with different delay times
 225                         unset( $info['params']['jobReleaseTimestamp'] );
 226                 }
 227                 return $info;
 228         }
 229
 230         /**
 231          * @see JobQueue::deduplicateRootJob()
 232          * @param string $key A key that identifies the task
 233          * @return Array
 234          * @since 1.21
 235          */
 236         public static function newRootJobParams( $key ) {
 237                 return array(
 238                         'rootJobSignature' => sha1( $key ),
 239                         'rootJobTimestamp' => wfTimestampNow()
 240                 );
 241         }
 242
 243         /**
 244          * @see JobQueue::deduplicateRootJob()
 245          * @return Array
 246          * @since 1.21
 247          */
 248         public function getRootJobParams() {
 249                 return array(
 250                         'rootJobSignature' => isset( $this->params['rootJobSignature'] )
 251                                 ? $this->params['rootJobSignature']
 252                                 : null,
 253                         'rootJobTimestamp' => isset( $this->params['rootJobTimestamp'] )
 254                                 ? $this->params['rootJobTimestamp']
 255                                 : null
 256                 );
 257         }
 258
 259         /**
 260          * @see JobQueue::deduplicateRootJob()
 261          * @return bool
 262          * @since 1.22
 263          */
 264         public function hasRootJobParams() {
 265                 return isset( $this->params['rootJobSignature'] )
 266                         && isset( $this->params['rootJobTimestamp'] );
 267         }
 268
 269         /**
 270          * Insert a single job into the queue.
 271          * @return bool true on success
 272          * @deprecated 1.21
 273          */
 274         public function insert() {
 275                 return JobQueueGroup::singleton()->push( $this );
 276         }
 277
 278         /**
 279          * @return string
 280          */
 281         public function toString() {
 282                 $paramString = '';
 283                 if ( $this->params ) {
 284                         foreach ( $this->params as $key => $value ) {
 285                                 if ( $paramString != '' ) {
 286                                         $paramString .= ' ';
 287                                 }
 288                                 if ( is_array( $value ) ) {
 289                                         $value = "array(" . count( $value ) . ")";
 290                                 } elseif ( is_object( $value ) && !method_exists( $value, '__toString' ) ) {
 291                                         $value = "object(" . get_class( $value ) . ")";
 292                                 }
 293                                 $value = (string)$value;
 294                                 if ( mb_strlen( $value ) > 1024 ) {
 295                                         $value = "string(" . mb_strlen( $value ) . ")";
 296                                 }
 297
 298                                 $paramString .= "$key=$value";
 299                         }
 300                 }
 301
 302                 if ( is_object( $this->title ) ) {
 303                         $s = "{$this->command} " . $this->title->getPrefixedDBkey();
 304                         if ( $paramString !== '' ) {
 305                                 $s .= ' ' . $paramString;
 306                         }
 307                         return $s;
 308                 } else {
 309                         return "{$this->command} $paramString";
 310                 }
 311         }
 312
 313         protected function setLastError( $error ) {
 314                 $this->error = $error;
 315         }
 316
 317         public function getLastError() {
 318                 return $this->error;
 319         }
 320 }