includes/job/Job.php

   1 <?php
   2 /**
   3  * Job queue task 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  * Using the class to push jobs onto queues is deprecated (use JobSpecification).
  28  *
  29  * @ingroup JobQueue
  30  */
  31 abstract class Job implements IJobSpecification {
  32         /** @var string */
  33         public $command;
  34
  35         /** @var array|bool Array of job parameters or false if none */
  36         public $params;
  37
  38         /** @var array Additional queue metadata */
  39         public $metadata = array();
  40
  41         /** @var Title */
  42         protected $title;
  43
  44         /** @var bool Expensive jobs may set this to true */
  45         protected $removeDuplicates;
  46
  47         /** @var string Text for error that occurred last */
  48         protected $error;
  49
  50         /*-------------------------------------------------------------------------
  51          * Abstract functions
  52          *------------------------------------------------------------------------*/
  53
  54         /**
  55          * Run the job
  56          * @return bool Success
  57          */
  58         abstract public function run();
  59
  60         /*-------------------------------------------------------------------------
  61          * Static functions
  62          *------------------------------------------------------------------------*/
  63
  64         /**
  65          * Create the appropriate object to handle a specific job
  66          *
  67          * @param string $command Job command
  68          * @param Title $title Associated title
  69          * @param array|bool $params Job parameters
  70          * @throws MWException
  71          * @return Job
  72          */
  73         public static function factory( $command, Title $title, $params = false ) {
  74                 global $wgJobClasses;
  75                 if ( isset( $wgJobClasses[$command] ) ) {
  76                         $class = $wgJobClasses[$command];
  77
  78                         return new $class( $title, $params );
  79                 }
  80                 throw new MWException( "Invalid job command `{$command}`" );
  81         }
  82
  83         /**
  84          * Batch-insert a group of jobs into the queue.
  85          * This will be wrapped in a transaction with a forced commit.
  86          *
  87          * This may add duplicate at insert time, but they will be
  88          * removed later on, when the first one is popped.
  89          *
  90          * @param array $jobs of Job objects
  91          * @return bool
  92          * @deprecated since 1.21
  93          */
  94         public static function batchInsert( $jobs ) {
  95                 return JobQueueGroup::singleton()->push( $jobs );
  96         }
  97
  98         /**
  99          * Insert a group of jobs into the queue.
 100          *
 101          * Same as batchInsert() but does not commit and can thus
 102          * be rolled-back as part of a larger transaction. However,
 103          * large batches of jobs can cause slave lag.
 104          *
 105          * @param array $jobs of Job objects
 106          * @return bool
 107          * @deprecated since 1.21
 108          */
 109         public static function safeBatchInsert( $jobs ) {
 110                 return JobQueueGroup::singleton()->push( $jobs, JobQueue::QOS_ATOMIC );
 111         }
 112
 113         /**
 114          * Pop a job of a certain type.  This tries less hard than pop() to
 115          * actually find a job; it may be adversely affected by concurrent job
 116          * runners.
 117          *
 118          * @param $type string
 119          * @return Job|bool Returns false if there are no jobs
 120          * @deprecated since 1.21
 121          */
 122         public static function pop_type( $type ) {
 123                 return JobQueueGroup::singleton()->get( $type )->pop();
 124         }
 125
 126         /**
 127          * Pop a job off the front of the queue.
 128          * This is subject to $wgJobTypesExcludedFromDefaultQueue.
 129          *
 130          * @return Job|bool False if there are no jobs
 131          * @deprecated since 1.21
 132          */
 133         public static function pop() {
 134                 return JobQueueGroup::singleton()->pop();
 135         }
 136
 137         /*-------------------------------------------------------------------------
 138          * Non-static functions
 139          *------------------------------------------------------------------------*/
 140
 141         /**
 142          * @param $command
 143          * @param $title
 144          * @param $params array|bool
 145          */
 146         public function __construct( $command, $title, $params = false ) {
 147                 $this->command = $command;
 148                 $this->title = $title;
 149                 $this->params = $params;
 150
 151                 // expensive jobs may set this to true
 152                 $this->removeDuplicates = false;
 153         }
 154
 155         /**
 156          * @return string
 157          */
 158         public function getType() {
 159                 return $this->command;
 160         }
 161
 162         /**
 163          * @return Title
 164          */
 165         public function getTitle() {
 166                 return $this->title;
 167         }
 168
 169         /**
 170          * @return array
 171          */
 172         public function getParams() {
 173                 return $this->params;
 174         }
 175
 176         /**
 177          * @return int|null UNIX timestamp to delay running this job until, otherwise null
 178          * @since 1.22
 179          */
 180         public function getReleaseTimestamp() {
 181                 return isset( $this->params['jobReleaseTimestamp'] )
 182                         ? wfTimestampOrNull( TS_UNIX, $this->params['jobReleaseTimestamp'] )
 183                         : null;
 184         }
 185
 186         /**
 187          * @return bool Whether only one of each identical set of jobs should be run
 188          */
 189         public function ignoreDuplicates() {
 190                 return $this->removeDuplicates;
 191         }
 192
 193         /**
 194          * @return bool Whether this job can be retried on failure by job runners
 195          * @since 1.21
 196          */
 197         public function allowRetries() {
 198                 return true;
 199         }
 200
 201         /**
 202          * @return integer Number of actually "work items" handled in this job
 203          * @see $wgJobBackoffThrottling
 204          * @since 1.23
 205          */
 206         public function workItemCount() {
 207                 return 1;
 208         }
 209
 210         /**
 211          * Subclasses may need to override this to make duplication detection work.
 212          * The resulting map conveys everything that makes the job unique. This is
 213          * only checked if ignoreDuplicates() returns true, meaning that duplicate
 214          * jobs are supposed to be ignored.
 215          *
 216          * @return array Map of key/values
 217          * @since 1.21
 218          */
 219         public function getDeduplicationInfo() {
 220                 $info = array(
 221                         'type' => $this->getType(),
 222                         'namespace' => $this->getTitle()->getNamespace(),
 223                         'title' => $this->getTitle()->getDBkey(),
 224                         'params' => $this->getParams()
 225                 );
 226                 if ( is_array( $info['params'] ) ) {
 227                         // Identical jobs with different "root" jobs should count as duplicates
 228                         unset( $info['params']['rootJobSignature'] );
 229                         unset( $info['params']['rootJobTimestamp'] );
 230                         // Likewise for jobs with different delay times
 231                         unset( $info['params']['jobReleaseTimestamp'] );
 232                 }
 233
 234                 return $info;
 235         }
 236
 237         /**
 238          * @see JobQueue::deduplicateRootJob()
 239          * @param string $key A key that identifies the task
 240          * @return array Map of:
 241          *   - rootJobSignature : hash (e.g. SHA1) that identifies the task
 242          *   - rootJobTimestamp : TS_MW timestamp of this instance of the task
 243          * @since 1.21
 244          */
 245         public static function newRootJobParams( $key ) {
 246                 return array(
 247                         'rootJobSignature' => sha1( $key ),
 248                         'rootJobTimestamp' => wfTimestampNow()
 249                 );
 250         }
 251
 252         /**
 253          * @see JobQueue::deduplicateRootJob()
 254          * @return array
 255          * @since 1.21
 256          */
 257         public function getRootJobParams() {
 258                 return array(
 259                         'rootJobSignature' => isset( $this->params['rootJobSignature'] )
 260                                 ? $this->params['rootJobSignature']
 261                                 : null,
 262                         'rootJobTimestamp' => isset( $this->params['rootJobTimestamp'] )
 263                                 ? $this->params['rootJobTimestamp']
 264                                 : null
 265                 );
 266         }
 267
 268         /**
 269          * @see JobQueue::deduplicateRootJob()
 270          * @return bool
 271          * @since 1.22
 272          */
 273         public function hasRootJobParams() {
 274                 return isset( $this->params['rootJobSignature'] )
 275                         && isset( $this->params['rootJobTimestamp'] );
 276         }
 277
 278         /**
 279          * Insert a single job into the queue.
 280          * @return bool true on success
 281          * @deprecated since 1.21
 282          */
 283         public function insert() {
 284                 return JobQueueGroup::singleton()->push( $this );
 285         }
 286
 287         /**
 288          * @return string
 289          */
 290         public function toString() {
 291                 $paramString = '';
 292                 if ( $this->params ) {
 293                         foreach ( $this->params as $key => $value ) {
 294                                 if ( $paramString != '' ) {
 295                                         $paramString .= ' ';
 296                                 }
 297                                 if ( is_array( $value ) ) {
 298                                         $value = "array(" . count( $value ) . ")";
 299                                 } elseif ( is_object( $value ) && !method_exists( $value, '__toString' ) ) {
 300                                         $value = "object(" . get_class( $value ) . ")";
 301                                 }
 302                                 $value = (string)$value;
 303                                 if ( mb_strlen( $value ) > 1024 ) {
 304                                         $value = "string(" . mb_strlen( $value ) . ")";
 305                                 }
 306
 307                                 $paramString .= "$key=$value";
 308                         }
 309                 }
 310
 311                 if ( is_object( $this->title ) ) {
 312                         $s = "{$this->command} " . $this->title->getPrefixedDBkey();
 313                         if ( $paramString !== '' ) {
 314                                 $s .= ' ' . $paramString;
 315                         }
 316
 317                         return $s;
 318                 } else {
 319                         return "{$this->command} $paramString";
 320                 }
 321         }
 322
 323         protected function setLastError( $error ) {
 324                 $this->error = $error;
 325         }
 326
 327         public function getLastError() {
 328                 return $this->error;
 329         }
 330 }