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 Array of job parameters */
  36         public $params;
  37
  38         /** @var array Additional queue metadata */
  39         public $metadata = [];
  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         /** @var callable[] */
  51         protected $teardownCallbacks = [];
  52
  53         /**
  54          * Run the job
  55          * @return bool Success
  56          */
  57         abstract public function run();
  58
  59         /**
  60          * Create the appropriate object to handle a specific job
  61          *
  62          * @param string $command Job command
  63          * @param Title $title Associated title
  64          * @param array $params Job parameters
  65          * @throws MWException
  66          * @return Job
  67          */
  68         public static function factory( $command, Title $title, $params = [] ) {
  69                 global $wgJobClasses;
  70
  71                 if ( isset( $wgJobClasses[$command] ) ) {
  72                         $class = $wgJobClasses[$command];
  73
  74                         $job = new $class( $title, $params );
  75                         $job->command = $command;
  76
  77                         return $job;
  78                 }
  79
  80                 throw new InvalidArgumentException( "Invalid job command '{$command}'" );
  81         }
  82
  83         /**
  84          * @param string $command
  85          * @param Title $title
  86          * @param array|bool $params Can not be === true
  87          */
  88         public function __construct( $command, $title, $params = false ) {
  89                 $this->command = $command;
  90                 $this->title = $title;
  91                 $this->params = is_array( $params ) ? $params : []; // sanity
  92
  93                 // expensive jobs may set this to true
  94                 $this->removeDuplicates = false;
  95         }
  96
  97         /**
  98          * Batch-insert a group of jobs into the queue.
  99          * This will be wrapped in a transaction with a forced commit.
 100          *
 101          * This may add duplicate at insert time, but they will be
 102          * removed later on, when the first one is popped.
 103          *
 104          * @param Job[] $jobs Array of Job objects
 105          * @return bool
 106          * @deprecated since 1.21
 107          */
 108         public static function batchInsert( $jobs ) {
 109                 wfDeprecated( __METHOD__, '1.21' );
 110                 JobQueueGroup::singleton()->push( $jobs );
 111                 return true;
 112         }
 113
 114         /**
 115          * @return string
 116          */
 117         public function getType() {
 118                 return $this->command;
 119         }
 120
 121         /**
 122          * @return Title
 123          */
 124         public function getTitle() {
 125                 return $this->title;
 126         }
 127
 128         /**
 129          * @return array
 130          */
 131         public function getParams() {
 132                 return $this->params;
 133         }
 134
 135         /**
 136          * @return int|null UNIX timestamp to delay running this job until, otherwise null
 137          * @since 1.22
 138          */
 139         public function getReleaseTimestamp() {
 140                 return isset( $this->params['jobReleaseTimestamp'] )
 141                         ? wfTimestampOrNull( TS_UNIX, $this->params['jobReleaseTimestamp'] )
 142                         : null;
 143         }
 144
 145         /**
 146          * @return int|null UNIX timestamp of when the job was queued, or null
 147          * @since 1.26
 148          */
 149         public function getQueuedTimestamp() {
 150                 return isset( $this->metadata['timestamp'] )
 151                         ? wfTimestampOrNull( TS_UNIX, $this->metadata['timestamp'] )
 152                         : null;
 153         }
 154
 155         /**
 156          * @return int|null UNIX timestamp of when the job was runnable, or null
 157          * @since 1.26
 158          */
 159         public function getReadyTimestamp() {
 160                 return $this->getReleaseTimestamp() ?: $this->getQueuedTimestamp();
 161         }
 162
 163         /**
 164          * Whether the queue should reject insertion of this job if a duplicate exists
 165          *
 166          * This can be used to avoid duplicated effort or combined with delayed jobs to
 167          * coalesce updates into larger batches. Claimed jobs are never treated as
 168          * duplicates of new jobs, and some queues may allow a few duplicates due to
 169          * network partitions and fail-over. Thus, additional locking is needed to
 170          * enforce mutual exclusion if this is really needed.
 171          *
 172          * @return bool
 173          */
 174         public function ignoreDuplicates() {
 175                 return $this->removeDuplicates;
 176         }
 177
 178         /**
 179          * @return bool Whether this job can be retried on failure by job runners
 180          * @since 1.21
 181          */
 182         public function allowRetries() {
 183                 return true;
 184         }
 185
 186         /**
 187          * @return int Number of actually "work items" handled in this job
 188          * @see $wgJobBackoffThrottling
 189          * @since 1.23
 190          */
 191         public function workItemCount() {
 192                 return 1;
 193         }
 194
 195         /**
 196          * Subclasses may need to override this to make duplication detection work.
 197          * The resulting map conveys everything that makes the job unique. This is
 198          * only checked if ignoreDuplicates() returns true, meaning that duplicate
 199          * jobs are supposed to be ignored.
 200          *
 201          * @return array Map of key/values
 202          * @since 1.21
 203          */
 204         public function getDeduplicationInfo() {
 205                 $info = [
 206                         'type' => $this->getType(),
 207                         'namespace' => $this->getTitle()->getNamespace(),
 208                         'title' => $this->getTitle()->getDBkey(),
 209                         'params' => $this->getParams()
 210                 ];
 211                 if ( is_array( $info['params'] ) ) {
 212                         // Identical jobs with different "root" jobs should count as duplicates
 213                         unset( $info['params']['rootJobSignature'] );
 214                         unset( $info['params']['rootJobTimestamp'] );
 215                         // Likewise for jobs with different delay times
 216                         unset( $info['params']['jobReleaseTimestamp'] );
 217                         // Queues pack and hash this array, so normalize the order
 218                         ksort( $info['params'] );
 219                 }
 220
 221                 return $info;
 222         }
 223
 224         /**
 225          * Get "root job" parameters for a task
 226          *
 227          * This is used to no-op redundant jobs, including child jobs of jobs,
 228          * as long as the children inherit the root job parameters. When a job
 229          * with root job parameters and "rootJobIsSelf" set is pushed, the
 230          * deduplicateRootJob() method is automatically called on it. If the
 231          * root job is only virtual and not actually pushed (e.g. the sub-jobs
 232          * are inserted directly), then call deduplicateRootJob() directly.
 233          *
 234          * @see JobQueue::deduplicateRootJob()
 235          *
 236          * @param string $key A key that identifies the task
 237          * @return array Map of:
 238          *   - rootJobIsSelf    : true
 239          *   - rootJobSignature : hash (e.g. SHA1) that identifies the task
 240          *   - rootJobTimestamp : TS_MW timestamp of this instance of the task
 241          * @since 1.21
 242          */
 243         public static function newRootJobParams( $key ) {
 244                 return [
 245                         'rootJobIsSelf'    => true,
 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 [
 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          * @see JobQueue::deduplicateRootJob()
 279          * @return bool Whether this is job is a root job
 280          */
 281         public function isRootJob() {
 282                 return $this->hasRootJobParams() && !empty( $this->params['rootJobIsSelf'] );
 283         }
 284
 285         /**
 286          * @param callable $callback
 287          * @since 1.27
 288          */
 289         protected function addTeardownCallback( $callback ) {
 290                 $this->teardownCallbacks[] = $callback;
 291         }
 292
 293         /**
 294          * Do any final cleanup after run(), deferred updates, and all DB commits happen
 295          *
 296          * @since 1.27
 297          */
 298         public function teardown() {
 299                 foreach ( $this->teardownCallbacks as $callback ) {
 300                         call_user_func( $callback );
 301                 }
 302         }
 303
 304         /**
 305          * Insert a single job into the queue.
 306          * @return bool True on success
 307          * @deprecated since 1.21
 308          */
 309         public function insert() {
 310                 JobQueueGroup::singleton()->push( $this );
 311                 return true;
 312         }
 313
 314         /**
 315          * @return string
 316          */
 317         public function toString() {
 318                 $truncFunc = function ( $value ) {
 319                         $value = (string)$value;
 320                         if ( mb_strlen( $value ) > 1024 ) {
 321                                 $value = "string(" . mb_strlen( $value ) . ")";
 322                         }
 323                         return $value;
 324                 };
 325
 326                 $paramString = '';
 327                 if ( $this->params ) {
 328                         foreach ( $this->params as $key => $value ) {
 329                                 if ( $paramString != '' ) {
 330                                         $paramString .= ' ';
 331                                 }
 332                                 if ( is_array( $value ) ) {
 333                                         $filteredValue = [];
 334                                         foreach ( $value as $k => $v ) {
 335                                                 if ( is_scalar( $v ) ) {
 336                                                         $filteredValue[$k] = $truncFunc( $v );
 337                                                 } else {
 338                                                         $filteredValue = null;
 339                                                         break;
 340                                                 }
 341                                         }
 342                                         if ( $filteredValue && count( $filteredValue ) < 10 ) {
 343                                                 $value = FormatJson::encode( $filteredValue );
 344                                         } else {
 345                                                 $value = "array(" . count( $value ) . ")";
 346                                         }
 347                                 } elseif ( is_object( $value ) && !method_exists( $value, '__toString' ) ) {
 348                                         $value = "object(" . get_class( $value ) . ")";
 349                                 }
 350
 351                                 $paramString .= "$key={$truncFunc( $value )}";
 352                         }
 353                 }
 354
 355                 $metaString = '';
 356                 foreach ( $this->metadata as $key => $value ) {
 357                         if ( is_scalar( $value ) && mb_strlen( $value ) < 1024 ) {
 358                                 $metaString .= ( $metaString ? ",$key=$value" : "$key=$value" );
 359                         }
 360                 }
 361
 362                 $s = $this->command;
 363                 if ( is_object( $this->title ) ) {
 364                         $s .= " {$this->title->getPrefixedDBkey()}";
 365                 }
 366                 if ( $paramString != '' ) {
 367                         $s .= " $paramString";
 368                 }
 369                 if ( $metaString != '' ) {
 370                         $s .= " ($metaString)";
 371                 }
 372
 373                 return $s;
 374         }
 375
 376         protected function setLastError( $error ) {
 377                 $this->error = $error;
 378         }
 379
 380         public function getLastError() {
 381                 return $this->error;
 382         }
 383 }