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 int Job identifier */
  32         public $id;
  33
  34         /** @var string */
  35         public $command;
  36
  37         /** @var array|bool Array of job parameters or false if none */
  38         public $params;
  39
  40         /** @var array Additional queue metadata */
  41         public $metadata = array();
  42
  43         /** @var Title */
  44         protected $title;
  45
  46         /** @var bool Expensive jobs may set this to true */
  47         protected $removeDuplicates;
  48
  49         /** @var string Text for error that occurred last */
  50         protected $error;
  51
  52         /*-------------------------------------------------------------------------
  53          * Abstract functions
  54          *------------------------------------------------------------------------*/
  55
  56         /**
  57          * Run the job
  58          * @return bool Success
  59          */
  60         abstract public function run();
  61
  62         /*-------------------------------------------------------------------------
  63          * Static functions
  64          *------------------------------------------------------------------------*/
  65
  66         /**
  67          * Create the appropriate object to handle a specific job
  68          *
  69          * @param string $command Job command
  70          * @param Title $title Associated title
  71          * @param array|bool $params Job parameters
  72          * @param int $id Job identifier
  73          * @throws MWException
  74          * @return Job
  75          */
  76         public static function factory( $command, Title $title, $params = false, $id = 0 ) {
  77                 global $wgJobClasses;
  78                 if ( isset( $wgJobClasses[$command] ) ) {
  79                         $class = $wgJobClasses[$command];
  80
  81                         return new $class( $title, $params, $id );
  82                 }
  83                 throw new MWException( "Invalid job command `{$command}`" );
  84         }
  85
  86         /**
  87          * Batch-insert a group of jobs into the queue.
  88          * This will be wrapped in a transaction with a forced commit.
  89          *
  90          * This may add duplicate at insert time, but they will be
  91          * removed later on, when the first one is popped.
  92          *
  93          * @param array $jobs of Job objects
  94          * @return bool
  95          * @deprecated since 1.21
  96          */
  97         public static function batchInsert( $jobs ) {
  98                 return JobQueueGroup::singleton()->push( $jobs );
  99         }
 100
 101         /**
 102          * Insert a group of jobs into the queue.
 103          *
 104          * Same as batchInsert() but does not commit and can thus
 105          * be rolled-back as part of a larger transaction. However,
 106          * large batches of jobs can cause slave lag.
 107          *
 108          * @param array $jobs of Job objects
 109          * @return bool
 110          * @deprecated since 1.21
 111          */
 112         public static function safeBatchInsert( $jobs ) {
 113                 return JobQueueGroup::singleton()->push( $jobs, JobQueue::QOS_ATOMIC );
 114         }
 115
 116         /**
 117          * Pop a job of a certain type.  This tries less hard than pop() to
 118          * actually find a job; it may be adversely affected by concurrent job
 119          * runners.
 120          *
 121          * @param $type string
 122          * @return Job|bool Returns false if there are no jobs
 123          * @deprecated since 1.21
 124          */
 125         public static function pop_type( $type ) {
 126                 return JobQueueGroup::singleton()->get( $type )->pop();
 127         }
 128
 129         /**
 130          * Pop a job off the front of the queue.
 131          * This is subject to $wgJobTypesExcludedFromDefaultQueue.
 132          *
 133          * @return Job|bool False if there are no jobs
 134          * @deprecated since 1.21
 135          */
 136         public static function pop() {
 137                 return JobQueueGroup::singleton()->pop();
 138         }
 139
 140         /*-------------------------------------------------------------------------
 141          * Non-static functions
 142          *------------------------------------------------------------------------*/
 143
 144         /**
 145          * @param $command
 146          * @param $title
 147          * @param $params array|bool
 148          * @param $id int
 149          */
 150         public function __construct( $command, $title, $params = false, $id = 0 ) {
 151                 $this->command = $command;
 152                 $this->title = $title;
 153                 $this->params = $params;
 154                 $this->id = $id;
 155
 156                 // expensive jobs may set this to true
 157                 $this->removeDuplicates = false;
 158         }
 159
 160         /**
 161          * @return int May be 0 for jobs stored outside the DB
 162          * @deprecated since 1.22
 163          */
 164         public function getId() {
 165                 return $this->id;
 166         }
 167
 168         /**
 169          * @return string
 170          */
 171         public function getType() {
 172                 return $this->command;
 173         }
 174
 175         /**
 176          * @return Title
 177          */
 178         public function getTitle() {
 179                 return $this->title;
 180         }
 181
 182         /**
 183          * @return array
 184          */
 185         public function getParams() {
 186                 return $this->params;
 187         }
 188
 189         /**
 190          * @return int|null UNIX timestamp to delay running this job until, otherwise null
 191          * @since 1.22
 192          */
 193         public function getReleaseTimestamp() {
 194                 return isset( $this->params['jobReleaseTimestamp'] )
 195                         ? wfTimestampOrNull( TS_UNIX, $this->params['jobReleaseTimestamp'] )
 196                         : null;
 197         }
 198
 199         /**
 200          * @return bool Whether only one of each identical set of jobs should be run
 201          */
 202         public function ignoreDuplicates() {
 203                 return $this->removeDuplicates;
 204         }
 205
 206         /**
 207          * @return bool Whether this job can be retried on failure by job runners
 208          * @since 1.21
 209          */
 210         public function allowRetries() {
 211                 return true;
 212         }
 213
 214         /**
 215          * Subclasses may need to override this to make duplication detection work.
 216          * The resulting map conveys everything that makes the job unique. This is
 217          * only checked if ignoreDuplicates() returns true, meaning that duplicate
 218          * jobs are supposed to be ignored.
 219          *
 220          * @return array Map of key/values
 221          * @since 1.21
 222          */
 223         public function getDeduplicationInfo() {
 224                 $info = array(
 225                         'type' => $this->getType(),
 226                         'namespace' => $this->getTitle()->getNamespace(),
 227                         'title' => $this->getTitle()->getDBkey(),
 228                         'params' => $this->getParams()
 229                 );
 230                 if ( is_array( $info['params'] ) ) {
 231                         // Identical jobs with different "root" jobs should count as duplicates
 232                         unset( $info['params']['rootJobSignature'] );
 233                         unset( $info['params']['rootJobTimestamp'] );
 234                         // Likewise for jobs with different delay times
 235                         unset( $info['params']['jobReleaseTimestamp'] );
 236                 }
 237
 238                 return $info;
 239         }
 240
 241         /**
 242          * @see JobQueue::deduplicateRootJob()
 243          * @param string $key A key that identifies the task
 244          * @return array Map of:
 245          *   - rootJobSignature : hash (e.g. SHA1) that identifies the task
 246          *   - rootJobTimestamp : TS_MW timestamp of this instance of the task
 247          * @since 1.21
 248          */
 249         public static function newRootJobParams( $key ) {
 250                 return array(
 251                         'rootJobSignature' => sha1( $key ),
 252                         'rootJobTimestamp' => wfTimestampNow()
 253                 );
 254         }
 255
 256         /**
 257          * @see JobQueue::deduplicateRootJob()
 258          * @return array
 259          * @since 1.21
 260          */
 261         public function getRootJobParams() {
 262                 return array(
 263                         'rootJobSignature' => isset( $this->params['rootJobSignature'] )
 264                                 ? $this->params['rootJobSignature']
 265                                 : null,
 266                         'rootJobTimestamp' => isset( $this->params['rootJobTimestamp'] )
 267                                 ? $this->params['rootJobTimestamp']
 268                                 : null
 269                 );
 270         }
 271
 272         /**
 273          * @see JobQueue::deduplicateRootJob()
 274          * @return bool
 275          * @since 1.22
 276          */
 277         public function hasRootJobParams() {
 278                 return isset( $this->params['rootJobSignature'] )
 279                         && isset( $this->params['rootJobTimestamp'] );
 280         }
 281
 282         /**
 283          * Insert a single job into the queue.
 284          * @return bool true on success
 285          * @deprecated since 1.21
 286          */
 287         public function insert() {
 288                 return JobQueueGroup::singleton()->push( $this );
 289         }
 290
 291         /**
 292          * @return string
 293          */
 294         public function toString() {
 295                 $paramString = '';
 296                 if ( $this->params ) {
 297                         foreach ( $this->params as $key => $value ) {
 298                                 if ( $paramString != '' ) {
 299                                         $paramString .= ' ';
 300                                 }
 301                                 if ( is_array( $value ) ) {
 302                                         $value = "array(" . count( $value ) . ")";
 303                                 } elseif ( is_object( $value ) && !method_exists( $value, '__toString' ) ) {
 304                                         $value = "object(" . get_class( $value ) . ")";
 305                                 }
 306                                 $value = (string)$value;
 307                                 if ( mb_strlen( $value ) > 1024 ) {
 308                                         $value = "string(" . mb_strlen( $value ) . ")";
 309                                 }
 310
 311                                 $paramString .= "$key=$value";
 312                         }
 313                 }
 314
 315                 if ( is_object( $this->title ) ) {
 316                         $s = "{$this->command} " . $this->title->getPrefixedDBkey();
 317                         if ( $paramString !== '' ) {
 318                                 $s .= ' ' . $paramString;
 319                         }
 320
 321                         return $s;
 322                 } else {
 323                         return "{$this->command} $paramString";
 324                 }
 325         }
 326
 327         protected function setLastError( $error ) {
 328                 $this->error = $error;
 329         }
 330
 331         public function getLastError() {
 332                 return $this->error;
 333         }
 334 }