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  * To push jobs onto queues, use JobQueueGroup::singleton()->push();
  27  *
  28  * @ingroup JobQueue
  29  */
  30 abstract class Job implements IJobSpecification {
  31         /** @var string */
  32         public $command;
  33
  34         /** @var array Array of job parameters */
  35         public $params;
  36
  37         /** @var array Additional queue metadata */
  38         public $metadata = [];
  39
  40         /** @var Title */
  41         protected $title;
  42
  43         /** @var bool Expensive jobs may set this to true */
  44         protected $removeDuplicates;
  45
  46         /** @var string Text for error that occurred last */
  47         protected $error;
  48
  49         /** @var callable[] */
  50         protected $teardownCallbacks = [];
  51
  52         /** @var int Bitfield of JOB_* class constants */
  53         protected $executionFlags = 0;
  54
  55         /** @var int Job must not be wrapped in the usual explicit LBFactory transaction round */
  56         const JOB_NO_EXPLICIT_TRX_ROUND = 1;
  57
  58         /**
  59          * Run the job
  60          * @return bool Success
  61          */
  62         abstract public function run();
  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 $params Job parameters
  70          * @throws MWException
  71          * @return Job
  72          */
  73         public static function factory( $command, Title $title, $params = [] ) {
  74                 global $wgJobClasses;
  75
  76                 if ( isset( $wgJobClasses[$command] ) ) {
  77                         $handler = $wgJobClasses[$command];
  78
  79                         if ( is_callable( $handler ) ) {
  80                                 $job = call_user_func( $handler, $title, $params );
  81                         } elseif ( class_exists( $handler ) ) {
  82                                 $job = new $handler( $title, $params );
  83                         } else {
  84                                 $job = null;
  85                         }
  86
  87                         if ( $job instanceof Job ) {
  88                                 $job->command = $command;
  89                                 return $job;
  90                         } else {
  91                                 throw new InvalidArgumentException( "Cannot instantiate job '$command': bad spec!" );
  92                         }
  93                 }
  94
  95                 throw new InvalidArgumentException( "Invalid job command '{$command}'" );
  96         }
  97
  98         /**
  99          * @param string $command
 100          * @param Title $title
 101          * @param array|bool $params Can not be === true
 102          */
 103         public function __construct( $command, $title, $params = false ) {
 104                 $this->command = $command;
 105                 $this->title = $title;
 106                 $this->params = is_array( $params ) ? $params : []; // sanity
 107
 108                 // expensive jobs may set this to true
 109                 $this->removeDuplicates = false;
 110
 111                 if ( !isset( $this->params['requestId'] ) ) {
 112                         $this->params['requestId'] = WebRequest::getRequestId();
 113                 }
 114         }
 115
 116         /**
 117          * @param int $flag JOB_* class constant
 118          * @return bool
 119          * @since 1.31
 120          */
 121         public function hasExecutionFlag( $flag ) {
 122                 return ( $this->executionFlags && $flag ) === $flag;
 123         }
 124
 125         /**
 126          * @return string
 127          */
 128         public function getType() {
 129                 return $this->command;
 130         }
 131
 132         /**
 133          * @return Title
 134          */
 135         public function getTitle() {
 136                 return $this->title;
 137         }
 138
 139         /**
 140          * @return array
 141          */
 142         public function getParams() {
 143                 return $this->params;
 144         }
 145
 146         /**
 147          * @return int|null UNIX timestamp to delay running this job until, otherwise null
 148          * @since 1.22
 149          */
 150         public function getReleaseTimestamp() {
 151                 return isset( $this->params['jobReleaseTimestamp'] )
 152                         ? wfTimestampOrNull( TS_UNIX, $this->params['jobReleaseTimestamp'] )
 153                         : null;
 154         }
 155
 156         /**
 157          * @return int|null UNIX timestamp of when the job was queued, or null
 158          * @since 1.26
 159          */
 160         public function getQueuedTimestamp() {
 161                 return isset( $this->metadata['timestamp'] )
 162                         ? wfTimestampOrNull( TS_UNIX, $this->metadata['timestamp'] )
 163                         : null;
 164         }
 165
 166         /**
 167          * @return string|null Id of the request that created this job. Follows
 168          *  jobs recursively, allowing to track the id of the request that started a
 169          *  job when jobs insert jobs which insert other jobs.
 170          * @since 1.27
 171          */
 172         public function getRequestId() {
 173                 return $this->params['requestId'] ?? null;
 174         }
 175
 176         /**
 177          * @return int|null UNIX timestamp of when the job was runnable, or null
 178          * @since 1.26
 179          */
 180         public function getReadyTimestamp() {
 181                 return $this->getReleaseTimestamp() ?: $this->getQueuedTimestamp();
 182         }
 183
 184         /**
 185          * Whether the queue should reject insertion of this job if a duplicate exists
 186          *
 187          * This can be used to avoid duplicated effort or combined with delayed jobs to
 188          * coalesce updates into larger batches. Claimed jobs are never treated as
 189          * duplicates of new jobs, and some queues may allow a few duplicates due to
 190          * network partitions and fail-over. Thus, additional locking is needed to
 191          * enforce mutual exclusion if this is really needed.
 192          *
 193          * @return bool
 194          */
 195         public function ignoreDuplicates() {
 196                 return $this->removeDuplicates;
 197         }
 198
 199         /**
 200          * @return bool Whether this job can be retried on failure by job runners
 201          * @since 1.21
 202          */
 203         public function allowRetries() {
 204                 return true;
 205         }
 206
 207         /**
 208          * @return int Number of actually "work items" handled in this job
 209          * @see $wgJobBackoffThrottling
 210          * @since 1.23
 211          */
 212         public function workItemCount() {
 213                 return 1;
 214         }
 215
 216         /**
 217          * Subclasses may need to override this to make duplication detection work.
 218          * The resulting map conveys everything that makes the job unique. This is
 219          * only checked if ignoreDuplicates() returns true, meaning that duplicate
 220          * jobs are supposed to be ignored.
 221          *
 222          * @return array Map of key/values
 223          * @since 1.21
 224          */
 225         public function getDeduplicationInfo() {
 226                 $info = [
 227                         'type' => $this->getType(),
 228                         'namespace' => $this->getTitle()->getNamespace(),
 229                         'title' => $this->getTitle()->getDBkey(),
 230                         'params' => $this->getParams()
 231                 ];
 232                 if ( is_array( $info['params'] ) ) {
 233                         // Identical jobs with different "root" jobs should count as duplicates
 234                         unset( $info['params']['rootJobSignature'] );
 235                         unset( $info['params']['rootJobTimestamp'] );
 236                         // Likewise for jobs with different delay times
 237                         unset( $info['params']['jobReleaseTimestamp'] );
 238                         // Identical jobs from different requests should count as duplicates
 239                         unset( $info['params']['requestId'] );
 240                         // Queues pack and hash this array, so normalize the order
 241                         ksort( $info['params'] );
 242                 }
 243
 244                 return $info;
 245         }
 246
 247         /**
 248          * Get "root job" parameters for a task
 249          *
 250          * This is used to no-op redundant jobs, including child jobs of jobs,
 251          * as long as the children inherit the root job parameters. When a job
 252          * with root job parameters and "rootJobIsSelf" set is pushed, the
 253          * deduplicateRootJob() method is automatically called on it. If the
 254          * root job is only virtual and not actually pushed (e.g. the sub-jobs
 255          * are inserted directly), then call deduplicateRootJob() directly.
 256          *
 257          * @see JobQueue::deduplicateRootJob()
 258          *
 259          * @param string $key A key that identifies the task
 260          * @return array Map of:
 261          *   - rootJobIsSelf    : true
 262          *   - rootJobSignature : hash (e.g. SHA1) that identifies the task
 263          *   - rootJobTimestamp : TS_MW timestamp of this instance of the task
 264          * @since 1.21
 265          */
 266         public static function newRootJobParams( $key ) {
 267                 return [
 268                         'rootJobIsSelf'    => true,
 269                         'rootJobSignature' => sha1( $key ),
 270                         'rootJobTimestamp' => wfTimestampNow()
 271                 ];
 272         }
 273
 274         /**
 275          * @see JobQueue::deduplicateRootJob()
 276          * @return array
 277          * @since 1.21
 278          */
 279         public function getRootJobParams() {
 280                 return [
 281                         'rootJobSignature' => $this->params['rootJobSignature'] ?? null,
 282                         'rootJobTimestamp' => $this->params['rootJobTimestamp'] ?? null
 283                 ];
 284         }
 285
 286         /**
 287          * @see JobQueue::deduplicateRootJob()
 288          * @return bool
 289          * @since 1.22
 290          */
 291         public function hasRootJobParams() {
 292                 return isset( $this->params['rootJobSignature'] )
 293                         && isset( $this->params['rootJobTimestamp'] );
 294         }
 295
 296         /**
 297          * @see JobQueue::deduplicateRootJob()
 298          * @return bool Whether this is job is a root job
 299          */
 300         public function isRootJob() {
 301                 return $this->hasRootJobParams() && !empty( $this->params['rootJobIsSelf'] );
 302         }
 303
 304         /**
 305          * @param callable $callback A function with one parameter, the success status, which will be
 306          *   false if the job failed or it succeeded but the DB changes could not be committed or
 307          *   any deferred updates threw an exception. (This parameter was added in 1.28.)
 308          * @since 1.27
 309          */
 310         protected function addTeardownCallback( $callback ) {
 311                 $this->teardownCallbacks[] = $callback;
 312         }
 313
 314         /**
 315          * Do any final cleanup after run(), deferred updates, and all DB commits happen
 316          * @param bool $status Whether the job, its deferred updates, and DB commit all succeeded
 317          * @since 1.27
 318          */
 319         public function teardown( $status ) {
 320                 foreach ( $this->teardownCallbacks as $callback ) {
 321                         call_user_func( $callback, $status );
 322                 }
 323         }
 324
 325         /**
 326          * @return string
 327          */
 328         public function toString() {
 329                 $paramString = '';
 330                 if ( $this->params ) {
 331                         foreach ( $this->params as $key => $value ) {
 332                                 if ( $paramString != '' ) {
 333                                         $paramString .= ' ';
 334                                 }
 335                                 if ( is_array( $value ) ) {
 336                                         $filteredValue = [];
 337                                         foreach ( $value as $k => $v ) {
 338                                                 $json = FormatJson::encode( $v );
 339                                                 if ( $json === false || mb_strlen( $json ) > 512 ) {
 340                                                         $filteredValue[$k] = gettype( $v ) . '(...)';
 341                                                 } else {
 342                                                         $filteredValue[$k] = $v;
 343                                                 }
 344                                         }
 345                                         if ( count( $filteredValue ) <= 10 ) {
 346                                                 $value = FormatJson::encode( $filteredValue );
 347                                         } else {
 348                                                 $value = "array(" . count( $value ) . ")";
 349                                         }
 350                                 } elseif ( is_object( $value ) && !method_exists( $value, '__toString' ) ) {
 351                                         $value = "object(" . get_class( $value ) . ")";
 352                                 }
 353
 354                                 $flatValue = (string)$value;
 355                                 if ( mb_strlen( $value ) > 1024 ) {
 356                                         $flatValue = "string(" . mb_strlen( $value ) . ")";
 357                                 }
 358
 359                                 $paramString .= "$key={$flatValue}";
 360                         }
 361                 }
 362
 363                 $metaString = '';
 364                 foreach ( $this->metadata as $key => $value ) {
 365                         if ( is_scalar( $value ) && mb_strlen( $value ) < 1024 ) {
 366                                 $metaString .= ( $metaString ? ",$key=$value" : "$key=$value" );
 367                         }
 368                 }
 369
 370                 $s = $this->command;
 371                 if ( is_object( $this->title ) ) {
 372                         $s .= " {$this->title->getPrefixedDBkey()}";
 373                 }
 374                 if ( $paramString != '' ) {
 375                         $s .= " $paramString";
 376                 }
 377                 if ( $metaString != '' ) {
 378                         $s .= " ($metaString)";
 379                 }
 380
 381                 return $s;
 382         }
 383
 384         protected function setLastError( $error ) {
 385                 $this->error = $error;
 386         }
 387
 388         public function getLastError() {
 389                 return $this->error;
 390         }
 391 }