includes/jobqueue/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 Job[] $jobs Array of Job objects
  91          * @return bool
  92          * @deprecated since 1.21
  93          */
  94         public static function batchInsert( $jobs ) {
  95                 JobQueueGroup::singleton()->push( $jobs );
  96                 return true;
  97         }
  98
  99         /**
 100          * Insert a group of jobs into the queue.
 101          *
 102          * Same as batchInsert() but does not commit and can thus
 103          * be rolled-back as part of a larger transaction. However,
 104          * large batches of jobs can cause slave lag.
 105          *
 106          * @param Job[] $jobs Array of Job objects
 107          * @return bool
 108          * @deprecated since 1.21
 109          */
 110         public static function safeBatchInsert( $jobs ) {
 111                 JobQueueGroup::singleton()->push( $jobs, JobQueue::QOS_ATOMIC );
 112                 return true;
 113         }
 114
 115         /**
 116          * Pop a job of a certain type.  This tries less hard than pop() to
 117          * actually find a job; it may be adversely affected by concurrent job
 118          * runners.
 119          *
 120          * @param string $type
 121          * @return Job|bool Returns false if there are no jobs
 122          * @deprecated since 1.21
 123          */
 124         public static function pop_type( $type ) {
 125                 return JobQueueGroup::singleton()->get( $type )->pop();
 126         }
 127
 128         /**
 129          * Pop a job off the front of the queue.
 130          * This is subject to $wgJobTypesExcludedFromDefaultQueue.
 131          *
 132          * @return Job|bool False if there are no jobs
 133          * @deprecated since 1.21
 134          */
 135         public static function pop() {
 136                 return JobQueueGroup::singleton()->pop();
 137         }
 138
 139         /*-------------------------------------------------------------------------
 140          * Non-static functions
 141          *------------------------------------------------------------------------*/
 142
 143         /**
 144          * @param string $command
 145          * @param Title $title
 146          * @param array|bool $params Can not be === true
 147          */
 148         public function __construct( $command, $title, $params = false ) {
 149                 $this->command = $command;
 150                 $this->title = $title;
 151                 $this->params = $params;
 152
 153                 // expensive jobs may set this to true
 154                 $this->removeDuplicates = false;
 155         }
 156
 157         /**
 158          * @return string
 159          */
 160         public function getType() {
 161                 return $this->command;
 162         }
 163
 164         /**
 165          * @return Title
 166          */
 167         public function getTitle() {
 168                 return $this->title;
 169         }
 170
 171         /**
 172          * @return array
 173          */
 174         public function getParams() {
 175                 return $this->params;
 176         }
 177
 178         /**
 179          * @return int|null UNIX timestamp to delay running this job until, otherwise null
 180          * @since 1.22
 181          */
 182         public function getReleaseTimestamp() {
 183                 return isset( $this->params['jobReleaseTimestamp'] )
 184                         ? wfTimestampOrNull( TS_UNIX, $this->params['jobReleaseTimestamp'] )
 185                         : null;
 186         }
 187
 188         /**
 189          * @return bool Whether only one of each identical set of jobs should be run
 190          */
 191         public function ignoreDuplicates() {
 192                 return $this->removeDuplicates;
 193         }
 194
 195         /**
 196          * @return bool Whether this job can be retried on failure by job runners
 197          * @since 1.21
 198          */
 199         public function allowRetries() {
 200                 return true;
 201         }
 202
 203         /**
 204          * @return int Number of actually "work items" handled in this job
 205          * @see $wgJobBackoffThrottling
 206          * @since 1.23
 207          */
 208         public function workItemCount() {
 209                 return 1;
 210         }
 211
 212         /**
 213          * Subclasses may need to override this to make duplication detection work.
 214          * The resulting map conveys everything that makes the job unique. This is
 215          * only checked if ignoreDuplicates() returns true, meaning that duplicate
 216          * jobs are supposed to be ignored.
 217          *
 218          * @return array Map of key/values
 219          * @since 1.21
 220          */
 221         public function getDeduplicationInfo() {
 222                 $info = array(
 223                         'type' => $this->getType(),
 224                         'namespace' => $this->getTitle()->getNamespace(),
 225                         'title' => $this->getTitle()->getDBkey(),
 226                         'params' => $this->getParams()
 227                 );
 228                 if ( is_array( $info['params'] ) ) {
 229                         // Identical jobs with different "root" jobs should count as duplicates
 230                         unset( $info['params']['rootJobSignature'] );
 231                         unset( $info['params']['rootJobTimestamp'] );
 232                         // Likewise for jobs with different delay times
 233                         unset( $info['params']['jobReleaseTimestamp'] );
 234                 }
 235
 236                 return $info;
 237         }
 238
 239         /**
 240          * @see JobQueue::deduplicateRootJob()
 241          * @param string $key A key that identifies the task
 242          * @return array Map of:
 243          *   - rootJobSignature : hash (e.g. SHA1) that identifies the task
 244          *   - rootJobTimestamp : TS_MW timestamp of this instance of the task
 245          * @since 1.21
 246          */
 247         public static function newRootJobParams( $key ) {
 248                 return array(
 249                         'rootJobSignature' => sha1( $key ),
 250                         'rootJobTimestamp' => wfTimestampNow()
 251                 );
 252         }
 253
 254         /**
 255          * @see JobQueue::deduplicateRootJob()
 256          * @return array
 257          * @since 1.21
 258          */
 259         public function getRootJobParams() {
 260                 return array(
 261                         'rootJobSignature' => isset( $this->params['rootJobSignature'] )
 262                                 ? $this->params['rootJobSignature']
 263                                 : null,
 264                         'rootJobTimestamp' => isset( $this->params['rootJobTimestamp'] )
 265                                 ? $this->params['rootJobTimestamp']
 266                                 : null
 267                 );
 268         }
 269
 270         /**
 271          * @see JobQueue::deduplicateRootJob()
 272          * @return bool
 273          * @since 1.22
 274          */
 275         public function hasRootJobParams() {
 276                 return isset( $this->params['rootJobSignature'] )
 277                         && isset( $this->params['rootJobTimestamp'] );
 278         }
 279
 280         /**
 281          * Insert a single job into the queue.
 282          * @return bool True on success
 283          * @deprecated since 1.21
 284          */
 285         public function insert() {
 286                 JobQueueGroup::singleton()->push( $this );
 287                 return true;
 288         }
 289
 290         /**
 291          * @return string
 292          */
 293         public function toString() {
 294                 $truncFunc = function ( $value ) {
 295                         $value = (string)$value;
 296                         if ( mb_strlen( $value ) > 1024 ) {
 297                                 $value = "string(" . mb_strlen( $value ) . ")";
 298                         }
 299                         return $value;
 300                 };
 301
 302                 $paramString = '';
 303                 if ( $this->params ) {
 304                         foreach ( $this->params as $key => $value ) {
 305                                 if ( $paramString != '' ) {
 306                                         $paramString .= ' ';
 307                                 }
 308                                 if ( is_array( $value ) ) {
 309                                         $filteredValue = array();
 310                                         foreach ( $value as $k => $v ) {
 311                                                 if ( is_scalar( $v ) ) {
 312                                                         $filteredValue[$k] = $truncFunc( $v );
 313                                                 } else {
 314                                                         $filteredValue = null;
 315                                                         break;
 316                                                 }
 317                                         }
 318                                         if ( $filteredValue ) {
 319                                                 $value = FormatJson::encode( $filteredValue );
 320                                         } else {
 321                                                 $value = "array(" . count( $value ) . ")";
 322                                         }
 323                                 } elseif ( is_object( $value ) && !method_exists( $value, '__toString' ) ) {
 324                                         $value = "object(" . get_class( $value ) . ")";
 325                                 }
 326
 327                                 $paramString .= "$key={$truncFunc( $value )}";
 328                         }
 329                 }
 330
 331                 if ( is_object( $this->title ) ) {
 332                         $s = "{$this->command} " . $this->title->getPrefixedDBkey();
 333                         if ( $paramString !== '' ) {
 334                                 $s .= ' ' . $paramString;
 335                         }
 336
 337                         return $s;
 338                 } else {
 339                         return "{$this->command} $paramString";
 340                 }
 341         }
 342
 343         protected function setLastError( $error ) {
 344                 $this->error = $error;
 345         }
 346
 347         public function getLastError() {
 348                 return $this->error;
 349         }
 350 }