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 $command String: Job command
  63          * @param $title Title: Associated title
  64          * @param $params Array|bool: Job parameters
  65          * @param $id Int: 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 $jobs array 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 $jobs array 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
 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 bool Whether only one of each identical set of jobs should be run
 181          */
 182         public function ignoreDuplicates() {
 183                 return $this->removeDuplicates;
 184         }
 185
 186         /**
 187          * @return bool Whether this job can be retried on failure by job runners
 188          */
 189         public function allowRetries() {
 190                 return true;
 191         }
 192
 193         /**
 194          * Subclasses may need to override this to make duplication detection work
 195          *
 196          * @return Array Map of key/values
 197          */
 198         public function getDeduplicationInfo() {
 199                 $info = array(
 200                         'type'      => $this->getType(),
 201                         'namespace' => $this->getTitle()->getNamespace(),
 202                         'title'     => $this->getTitle()->getDBkey(),
 203                         'params'    => $this->getParams()
 204                 );
 205                 // Identical jobs with different "root" jobs should count as duplicates
 206                 if ( is_array( $info['params'] ) ) {
 207                         unset( $info['params']['rootJobSignature'] );
 208                         unset( $info['params']['rootJobTimestamp'] );
 209                 }
 210                 return $info;
 211         }
 212
 213         /**
 214          * @param $key string A key that identifies the task
 215          * @return Array
 216          */
 217         public static function newRootJobParams( $key ) {
 218                 return array(
 219                         'rootJobSignature' => sha1( $key ),
 220                         'rootJobTimestamp' => wfTimestampNow()
 221                 );
 222         }
 223
 224         /**
 225          * @return Array
 226          */
 227         public function getRootJobParams() {
 228                 return array(
 229                         'rootJobSignature' => isset( $this->params['rootJobSignature'] )
 230                                 ? $this->params['rootJobSignature']
 231                                 : null,
 232                         'rootJobTimestamp' => isset( $this->params['rootJobTimestamp'] )
 233                                 ? $this->params['rootJobTimestamp']
 234                                 : null
 235                 );
 236         }
 237
 238         /**
 239          * Insert a single job into the queue.
 240          * @return bool true on success
 241          * @deprecated 1.21
 242          */
 243         public function insert() {
 244                 return JobQueueGroup::singleton()->push( $this );
 245         }
 246
 247         /**
 248          * @return string
 249          */
 250         public function toString() {
 251                 $paramString = '';
 252                 if ( $this->params ) {
 253                         foreach ( $this->params as $key => $value ) {
 254                                 if ( $paramString != '' ) {
 255                                         $paramString .= ' ';
 256                                 }
 257                                 if ( is_array( $value ) ) {
 258                                         $value = "array(" . count( $value ) . ")";
 259                                 } elseif ( is_object( $value ) && !method_exists( $value, '__toString' ) ) {
 260                                         $value = "object(" . get_class( $value ) . ")";
 261                                 }
 262                                 $value = (string)$value;
 263                                 if ( mb_strlen( $value ) > 1024 ) {
 264                                         $value = "string(" . mb_strlen( $value ) . ")";
 265                                 }
 266
 267                                 $paramString .= "$key=$value";
 268                         }
 269                 }
 270
 271                 if ( is_object( $this->title ) ) {
 272                         $s = "{$this->command} " . $this->title->getPrefixedDBkey();
 273                         if ( $paramString !== '' ) {
 274                                 $s .= ' ' . $paramString;
 275                         }
 276                         return $s;
 277                 } else {
 278                         return "{$this->command} $paramString";
 279                 }
 280         }
 281
 282         protected function setLastError( $error ) {
 283                 $this->error = $error;
 284         }
 285
 286         public function getLastError() {
 287                 return $this->error;
 288         }
 289 }