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         /** @var string */
  32         public $command;
  33
  34         /** @var array|bool Array of job parameters or false if none */
  35         public $params;
  36
  37         /** @var array Additional queue metadata */
  38         public $metadata = array();
  39
  40         /** @var Title */
  41         protected $title;
  42
  43         /** @var bool Expensive jobs may set this to true */
  44         protected $removeDuplicates;
  45
  46         /** @var string Text for error that occurred last */
  47         protected $error;
  48
  49         /*-------------------------------------------------------------------------
  50          * Abstract functions
  51          *------------------------------------------------------------------------*/
  52
  53         /**
  54          * Run the job
  55          * @return bool Success
  56          */
  57         abstract public function run();
  58
  59         /*-------------------------------------------------------------------------
  60          * Static functions
  61          *------------------------------------------------------------------------*/
  62
  63         /**
  64          * Create the appropriate object to handle a specific job
  65          *
  66          * @param string $command Job command
  67          * @param Title $title Associated title
  68          * @param array|bool $params Job parameters
  69          * @throws MWException
  70          * @return Job
  71          */
  72         public static function factory( $command, Title $title, $params = false ) {
  73                 global $wgJobClasses;
  74                 if ( isset( $wgJobClasses[$command] ) ) {
  75                         $class = $wgJobClasses[$command];
  76
  77                         return new $class( $title, $params );
  78                 }
  79                 throw new MWException( "Invalid job command `{$command}`" );
  80         }
  81
  82         /**
  83          * Batch-insert a group of jobs into the queue.
  84          * This will be wrapped in a transaction with a forced commit.
  85          *
  86          * This may add duplicate at insert time, but they will be
  87          * removed later on, when the first one is popped.
  88          *
  89          * @param array $jobs of Job objects
  90          * @return bool
  91          * @deprecated since 1.21
  92          */
  93         public static function batchInsert( $jobs ) {
  94                 return JobQueueGroup::singleton()->push( $jobs );
  95         }
  96
  97         /**
  98          * Insert a group of jobs into the queue.
  99          *
 100          * Same as batchInsert() but does not commit and can thus
 101          * be rolled-back as part of a larger transaction. However,
 102          * large batches of jobs can cause slave lag.
 103          *
 104          * @param array $jobs of Job objects
 105          * @return bool
 106          * @deprecated since 1.21
 107          */
 108         public static function safeBatchInsert( $jobs ) {
 109                 return JobQueueGroup::singleton()->push( $jobs, JobQueue::QOS_ATOMIC );
 110         }
 111
 112         /**
 113          * Pop a job of a certain type.  This tries less hard than pop() to
 114          * actually find a job; it may be adversely affected by concurrent job
 115          * runners.
 116          *
 117          * @param $type string
 118          * @return Job|bool Returns false if there are no jobs
 119          * @deprecated since 1.21
 120          */
 121         public static function pop_type( $type ) {
 122                 return JobQueueGroup::singleton()->get( $type )->pop();
 123         }
 124
 125         /**
 126          * Pop a job off the front of the queue.
 127          * This is subject to $wgJobTypesExcludedFromDefaultQueue.
 128          *
 129          * @return Job|bool False if there are no jobs
 130          * @deprecated since 1.21
 131          */
 132         public static function pop() {
 133                 return JobQueueGroup::singleton()->pop();
 134         }
 135
 136         /*-------------------------------------------------------------------------
 137          * Non-static functions
 138          *------------------------------------------------------------------------*/
 139
 140         /**
 141          * @param $command
 142          * @param $title
 143          * @param $params array|bool
 144          */
 145         public function __construct( $command, $title, $params = false ) {
 146                 $this->command = $command;
 147                 $this->title = $title;
 148                 $this->params = $params;
 149
 150                 // expensive jobs may set this to true
 151                 $this->removeDuplicates = false;
 152         }
 153
 154         /**
 155          * @return string
 156          */
 157         public function getType() {
 158                 return $this->command;
 159         }
 160
 161         /**
 162          * @return Title
 163          */
 164         public function getTitle() {
 165                 return $this->title;
 166         }
 167
 168         /**
 169          * @return array
 170          */
 171         public function getParams() {
 172                 return $this->params;
 173         }
 174
 175         /**
 176          * @return int|null UNIX timestamp to delay running this job until, otherwise null
 177          * @since 1.22
 178          */
 179         public function getReleaseTimestamp() {
 180                 return isset( $this->params['jobReleaseTimestamp'] )
 181                         ? wfTimestampOrNull( TS_UNIX, $this->params['jobReleaseTimestamp'] )
 182                         : null;
 183         }
 184
 185         /**
 186          * @return bool Whether only one of each identical set of jobs should be run
 187          */
 188         public function ignoreDuplicates() {
 189                 return $this->removeDuplicates;
 190         }
 191
 192         /**
 193          * @return bool Whether this job can be retried on failure by job runners
 194          * @since 1.21
 195          */
 196         public function allowRetries() {
 197                 return true;
 198         }
 199
 200         /**
 201          * @return integer Number of actually "work items" handled in this job
 202          * @see $wgJobBackoffThrottling
 203          * @since 1.23
 204          */
 205         public function workItemCount() {
 206                 return 1;
 207         }
 208
 209         /**
 210          * Subclasses may need to override this to make duplication detection work.
 211          * The resulting map conveys everything that makes the job unique. This is
 212          * only checked if ignoreDuplicates() returns true, meaning that duplicate
 213          * jobs are supposed to be ignored.
 214          *
 215          * @return array Map of key/values
 216          * @since 1.21
 217          */
 218         public function getDeduplicationInfo() {
 219                 $info = array(
 220                         'type' => $this->getType(),
 221                         'namespace' => $this->getTitle()->getNamespace(),
 222                         'title' => $this->getTitle()->getDBkey(),
 223                         'params' => $this->getParams()
 224                 );
 225                 if ( is_array( $info['params'] ) ) {
 226                         // Identical jobs with different "root" jobs should count as duplicates
 227                         unset( $info['params']['rootJobSignature'] );
 228                         unset( $info['params']['rootJobTimestamp'] );
 229                         // Likewise for jobs with different delay times
 230                         unset( $info['params']['jobReleaseTimestamp'] );
 231                 }
 232
 233                 return $info;
 234         }
 235
 236         /**
 237          * @see JobQueue::deduplicateRootJob()
 238          * @param string $key A key that identifies the task
 239          * @return array Map of:
 240          *   - rootJobSignature : hash (e.g. SHA1) that identifies the task
 241          *   - rootJobTimestamp : TS_MW timestamp of this instance of the task
 242          * @since 1.21
 243          */
 244         public static function newRootJobParams( $key ) {
 245                 return array(
 246                         'rootJobSignature' => sha1( $key ),
 247                         'rootJobTimestamp' => wfTimestampNow()
 248                 );
 249         }
 250
 251         /**
 252          * @see JobQueue::deduplicateRootJob()
 253          * @return array
 254          * @since 1.21
 255          */
 256         public function getRootJobParams() {
 257                 return array(
 258                         'rootJobSignature' => isset( $this->params['rootJobSignature'] )
 259                                 ? $this->params['rootJobSignature']
 260                                 : null,
 261                         'rootJobTimestamp' => isset( $this->params['rootJobTimestamp'] )
 262                                 ? $this->params['rootJobTimestamp']
 263                                 : null
 264                 );
 265         }
 266
 267         /**
 268          * @see JobQueue::deduplicateRootJob()
 269          * @return bool
 270          * @since 1.22
 271          */
 272         public function hasRootJobParams() {
 273                 return isset( $this->params['rootJobSignature'] )
 274                         && isset( $this->params['rootJobTimestamp'] );
 275         }
 276
 277         /**
 278          * Insert a single job into the queue.
 279          * @return bool true on success
 280          * @deprecated since 1.21
 281          */
 282         public function insert() {
 283                 return JobQueueGroup::singleton()->push( $this );
 284         }
 285
 286         /**
 287          * @return string
 288          */
 289         public function toString() {
 290                 $paramString = '';
 291                 if ( $this->params ) {
 292                         foreach ( $this->params as $key => $value ) {
 293                                 if ( $paramString != '' ) {
 294                                         $paramString .= ' ';
 295                                 }
 296                                 if ( is_array( $value ) ) {
 297                                         $value = "array(" . count( $value ) . ")";
 298                                 } elseif ( is_object( $value ) && !method_exists( $value, '__toString' ) ) {
 299                                         $value = "object(" . get_class( $value ) . ")";
 300                                 }
 301                                 $value = (string)$value;
 302                                 if ( mb_strlen( $value ) > 1024 ) {
 303                                         $value = "string(" . mb_strlen( $value ) . ")";
 304                                 }
 305
 306                                 $paramString .= "$key=$value";
 307                         }
 308                 }
 309
 310                 if ( is_object( $this->title ) ) {
 311                         $s = "{$this->command} " . $this->title->getPrefixedDBkey();
 312                         if ( $paramString !== '' ) {
 313                                 $s .= ' ' . $paramString;
 314                         }
 315
 316                         return $s;
 317                 } else {
 318                         return "{$this->command} $paramString";
 319                 }
 320         }
 321
 322         protected function setLastError( $error ) {
 323                 $this->error = $error;
 324         }
 325
 326         public function getLastError() {
 327                 return $this->error;
 328         }
 329 }