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          * Run the job
  52          * @return bool Success
  53          */
  54         abstract public function run();
  55
  56         /**
  57          * Create the appropriate object to handle a specific job
  58          *
  59          * @param string $command Job command
  60          * @param Title $title Associated title
  61          * @param array|bool $params Job parameters
  62          * @throws MWException
  63          * @return Job
  64          */
  65         public static function factory( $command, Title $title, $params = false ) {
  66                 global $wgJobClasses;
  67                 if ( isset( $wgJobClasses[$command] ) ) {
  68                         $class = $wgJobClasses[$command];
  69
  70                         return new $class( $title, $params );
  71                 }
  72                 throw new MWException( "Invalid job command `{$command}`" );
  73         }
  74
  75         /**
  76          * @param string $command
  77          * @param Title $title
  78          * @param array|bool $params Can not be === true
  79          */
  80         public function __construct( $command, $title, $params = false ) {
  81                 $this->command = $command;
  82                 $this->title = $title;
  83                 $this->params = $params;
  84
  85                 // expensive jobs may set this to true
  86                 $this->removeDuplicates = false;
  87         }
  88
  89         /**
  90          * Batch-insert a group of jobs into the queue.
  91          * This will be wrapped in a transaction with a forced commit.
  92          *
  93          * This may add duplicate at insert time, but they will be
  94          * removed later on, when the first one is popped.
  95          *
  96          * @param Job[] $jobs Array of Job objects
  97          * @return bool
  98          * @deprecated since 1.21
  99          */
 100         public static function batchInsert( $jobs ) {
 101                 wfDeprecated( __METHOD__, '1.21' );
 102                 JobQueueGroup::singleton()->push( $jobs );
 103                 return true;
 104         }
 105
 106         /**
 107          * @return string
 108          */
 109         public function getType() {
 110                 return $this->command;
 111         }
 112
 113         /**
 114          * @return Title
 115          */
 116         public function getTitle() {
 117                 return $this->title;
 118         }
 119
 120         /**
 121          * @return array
 122          */
 123         public function getParams() {
 124                 return $this->params;
 125         }
 126
 127         /**
 128          * @return int|null UNIX timestamp to delay running this job until, otherwise null
 129          * @since 1.22
 130          */
 131         public function getReleaseTimestamp() {
 132                 return isset( $this->params['jobReleaseTimestamp'] )
 133                         ? wfTimestampOrNull( TS_UNIX, $this->params['jobReleaseTimestamp'] )
 134                         : null;
 135         }
 136
 137         /**
 138          * Whether the queue should reject insertion of this job if a duplicate exists
 139          *
 140          * This can be used to avoid duplicated effort or combined with delayed jobs to
 141          * coalesce updates into larger batches. Claimed jobs are never treated as
 142          * duplicates of new jobs, and some queues may allow a few duplicates due to
 143          * network partitions and fail-over. Thus, additional locking is needed to
 144          * enforce mutual exclusion if this is really needed.
 145          *
 146          * @return bool
 147          */
 148         public function ignoreDuplicates() {
 149                 return $this->removeDuplicates;
 150         }
 151
 152         /**
 153          * @return bool Whether this job can be retried on failure by job runners
 154          * @since 1.21
 155          */
 156         public function allowRetries() {
 157                 return true;
 158         }
 159
 160         /**
 161          * @return int Number of actually "work items" handled in this job
 162          * @see $wgJobBackoffThrottling
 163          * @since 1.23
 164          */
 165         public function workItemCount() {
 166                 return 1;
 167         }
 168
 169         /**
 170          * Subclasses may need to override this to make duplication detection work.
 171          * The resulting map conveys everything that makes the job unique. This is
 172          * only checked if ignoreDuplicates() returns true, meaning that duplicate
 173          * jobs are supposed to be ignored.
 174          *
 175          * @return array Map of key/values
 176          * @since 1.21
 177          */
 178         public function getDeduplicationInfo() {
 179                 $info = array(
 180                         'type' => $this->getType(),
 181                         'namespace' => $this->getTitle()->getNamespace(),
 182                         'title' => $this->getTitle()->getDBkey(),
 183                         'params' => $this->getParams()
 184                 );
 185                 if ( is_array( $info['params'] ) ) {
 186                         // Identical jobs with different "root" jobs should count as duplicates
 187                         unset( $info['params']['rootJobSignature'] );
 188                         unset( $info['params']['rootJobTimestamp'] );
 189                         // Likewise for jobs with different delay times
 190                         unset( $info['params']['jobReleaseTimestamp'] );
 191                 }
 192
 193                 return $info;
 194         }
 195
 196         /**
 197          * @see JobQueue::deduplicateRootJob()
 198          * @param string $key A key that identifies the task
 199          * @return array Map of:
 200          *   - rootJobSignature : hash (e.g. SHA1) that identifies the task
 201          *   - rootJobTimestamp : TS_MW timestamp of this instance of the task
 202          * @since 1.21
 203          */
 204         public static function newRootJobParams( $key ) {
 205                 return array(
 206                         'rootJobSignature' => sha1( $key ),
 207                         'rootJobTimestamp' => wfTimestampNow()
 208                 );
 209         }
 210
 211         /**
 212          * @see JobQueue::deduplicateRootJob()
 213          * @return array
 214          * @since 1.21
 215          */
 216         public function getRootJobParams() {
 217                 return array(
 218                         'rootJobSignature' => isset( $this->params['rootJobSignature'] )
 219                                 ? $this->params['rootJobSignature']
 220                                 : null,
 221                         'rootJobTimestamp' => isset( $this->params['rootJobTimestamp'] )
 222                                 ? $this->params['rootJobTimestamp']
 223                                 : null
 224                 );
 225         }
 226
 227         /**
 228          * @see JobQueue::deduplicateRootJob()
 229          * @return bool
 230          * @since 1.22
 231          */
 232         public function hasRootJobParams() {
 233                 return isset( $this->params['rootJobSignature'] )
 234                         && isset( $this->params['rootJobTimestamp'] );
 235         }
 236
 237         /**
 238          * Insert a single job into the queue.
 239          * @return bool True on success
 240          * @deprecated since 1.21
 241          */
 242         public function insert() {
 243                 JobQueueGroup::singleton()->push( $this );
 244                 return true;
 245         }
 246
 247         /**
 248          * @return string
 249          */
 250         public function toString() {
 251                 $truncFunc = function ( $value ) {
 252                         $value = (string)$value;
 253                         if ( mb_strlen( $value ) > 1024 ) {
 254                                 $value = "string(" . mb_strlen( $value ) . ")";
 255                         }
 256                         return $value;
 257                 };
 258
 259                 $paramString = '';
 260                 if ( $this->params ) {
 261                         foreach ( $this->params as $key => $value ) {
 262                                 if ( $paramString != '' ) {
 263                                         $paramString .= ' ';
 264                                 }
 265                                 if ( is_array( $value ) ) {
 266                                         $filteredValue = array();
 267                                         foreach ( $value as $k => $v ) {
 268                                                 if ( is_scalar( $v ) ) {
 269                                                         $filteredValue[$k] = $truncFunc( $v );
 270                                                 } else {
 271                                                         $filteredValue = null;
 272                                                         break;
 273                                                 }
 274                                         }
 275                                         if ( $filteredValue && count( $filteredValue ) < 10 ) {
 276                                                 $value = FormatJson::encode( $filteredValue );
 277                                         } else {
 278                                                 $value = "array(" . count( $value ) . ")";
 279                                         }
 280                                 } elseif ( is_object( $value ) && !method_exists( $value, '__toString' ) ) {
 281                                         $value = "object(" . get_class( $value ) . ")";
 282                                 }
 283
 284                                 $paramString .= "$key={$truncFunc( $value )}";
 285                         }
 286                 }
 287
 288                 $metaString = '';
 289                 foreach ( $this->metadata as $key => $value ) {
 290                         if ( is_scalar( $value ) && mb_strlen( $value ) < 1024 ) {
 291                                 $metaString .= ( $metaString ? ",$key=$value" : "$key=$value" );
 292                         }
 293                 }
 294
 295                 $s = $this->command;
 296                 if ( is_object( $this->title ) ) {
 297                         $s .= " {$this->title->getPrefixedDBkey()}";
 298                 }
 299                 if ( $paramString != '' ) {
 300                         $s .= " $paramString";
 301                 }
 302                 if ( $metaString != '' ) {
 303                         $s .= " ($metaString)";
 304                 }
 305
 306                 return $s;
 307         }
 308
 309         protected function setLastError( $error ) {
 310                 $this->error = $error;
 311         }
 312
 313         public function getLastError() {
 314                 return $this->error;
 315         }
 316 }