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 = false;
  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 array|Title $params Job parameters
  69          * @throws InvalidArgumentException
  70          * @return Job
  71          */
  72         public static function factory( $command, $params = [] ) {
  73                 global $wgJobClasses;
  74
  75                 if ( $params instanceof Title ) {
  76                         // Backwards compatibility for old signature ($command, $title, $params)
  77                         $title = $params;
  78                         $params = func_num_args() >= 3 ? func_get_arg( 2 ) : [];
  79                 } else {
  80                         // Subclasses can override getTitle() to return something more meaningful
  81                         $title = Title::makeTitle( NS_SPECIAL, 'Blankpage' );
  82                 }
  83
  84                 if ( isset( $wgJobClasses[$command] ) ) {
  85                         $handler = $wgJobClasses[$command];
  86
  87                         if ( is_callable( $handler ) ) {
  88                                 $job = call_user_func( $handler, $title, $params );
  89                         } elseif ( class_exists( $handler ) ) {
  90                                 $job = new $handler( $title, $params );
  91                         } else {
  92                                 $job = null;
  93                         }
  94
  95                         if ( $job instanceof Job ) {
  96                                 $job->command = $command;
  97
  98                                 return $job;
  99                         } else {
 100                                 throw new InvalidArgumentException( "Could instantiate job '$command': bad spec!" );
 101                         }
 102                 }
 103
 104                 throw new InvalidArgumentException( "Invalid job command '{$command}'" );
 105         }
 106
 107         /**
 108          * @param string $command
 109          * @param array|Title|null $params
 110          */
 111         public function __construct( $command, $params = null ) {
 112                 if ( $params instanceof Title ) {
 113                         // Backwards compatibility for old signature ($command, $title, $params)
 114                         $title = $params;
 115                         $params = func_get_arg( 2 );
 116                 } else {
 117                         // Subclasses can override getTitle() to return something more meaningful
 118                         $title = Title::makeTitle( NS_SPECIAL, 'Blankpage' );
 119                 }
 120
 121                 $this->command = $command;
 122                 $this->title = $title;
 123                 $this->params = is_array( $params ) ? $params : [];
 124                 if ( !isset( $this->params['requestId'] ) ) {
 125                         $this->params['requestId'] = WebRequest::getRequestId();
 126                 }
 127         }
 128
 129         /**
 130          * @param int $flag JOB_* class constant
 131          * @return bool
 132          * @since 1.31
 133          */
 134         public function hasExecutionFlag( $flag ) {
 135                 return ( $this->executionFlags & $flag ) === $flag;
 136         }
 137
 138         /**
 139          * @return string
 140          */
 141         public function getType() {
 142                 return $this->command;
 143         }
 144
 145         /**
 146          * @return Title
 147          */
 148         public function getTitle() {
 149                 return $this->title;
 150         }
 151
 152         /**
 153          * @return array
 154          */
 155         public function getParams() {
 156                 return $this->params;
 157         }
 158
 159         /**
 160          * @param string|null $field Metadata field or null to get all the metadata
 161          * @return mixed|null Value; null if missing
 162          * @since 1.33
 163          */
 164         public function getMetadata( $field = null ) {
 165                 if ( $field === null ) {
 166                         return $this->metadata;
 167                 }
 168
 169                 return $this->metadata[$field] ?? null;
 170         }
 171
 172         /**
 173          * @param string $field Key name to set the value for
 174          * @param mixed $value The value to set the field for
 175          * @return mixed|null The prior field value; null if missing
 176          * @since 1.33
 177          */
 178         public function setMetadata( $field, $value ) {
 179                 $old = $this->getMetadata( $field );
 180                 if ( $value === null ) {
 181                         unset( $this->metadata[$field] );
 182                 } else {
 183                         $this->metadata[$field] = $value;
 184                 }
 185
 186                 return $old;
 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 int|null UNIX timestamp of when the job was queued, or null
 201          * @since 1.26
 202          */
 203         public function getQueuedTimestamp() {
 204                 return isset( $this->metadata['timestamp'] )
 205                         ? wfTimestampOrNull( TS_UNIX, $this->metadata['timestamp'] )
 206                         : null;
 207         }
 208
 209         /**
 210          * @return string|null Id of the request that created this job. Follows
 211          *  jobs recursively, allowing to track the id of the request that started a
 212          *  job when jobs insert jobs which insert other jobs.
 213          * @since 1.27
 214          */
 215         public function getRequestId() {
 216                 return $this->params['requestId'] ?? null;
 217         }
 218
 219         /**
 220          * @return int|null UNIX timestamp of when the job was runnable, or null
 221          * @since 1.26
 222          */
 223         public function getReadyTimestamp() {
 224                 return $this->getReleaseTimestamp() ?: $this->getQueuedTimestamp();
 225         }
 226
 227         /**
 228          * Whether the queue should reject insertion of this job if a duplicate exists
 229          *
 230          * This can be used to avoid duplicated effort or combined with delayed jobs to
 231          * coalesce updates into larger batches. Claimed jobs are never treated as
 232          * duplicates of new jobs, and some queues may allow a few duplicates due to
 233          * network partitions and fail-over. Thus, additional locking is needed to
 234          * enforce mutual exclusion if this is really needed.
 235          *
 236          * @return bool
 237          */
 238         public function ignoreDuplicates() {
 239                 return $this->removeDuplicates;
 240         }
 241
 242         /**
 243          * @return bool Whether this job can be retried on failure by job runners
 244          * @since 1.21
 245          */
 246         public function allowRetries() {
 247                 return true;
 248         }
 249
 250         /**
 251          * @return int Number of actually "work items" handled in this job
 252          * @see $wgJobBackoffThrottling
 253          * @since 1.23
 254          */
 255         public function workItemCount() {
 256                 return 1;
 257         }
 258
 259         /**
 260          * Subclasses may need to override this to make duplication detection work.
 261          * The resulting map conveys everything that makes the job unique. This is
 262          * only checked if ignoreDuplicates() returns true, meaning that duplicate
 263          * jobs are supposed to be ignored.
 264          *
 265          * @return array Map of key/values
 266          * @since 1.21
 267          */
 268         public function getDeduplicationInfo() {
 269                 $info = [
 270                         'type' => $this->getType(),
 271                         'namespace' => $this->getTitle()->getNamespace(),
 272                         'title' => $this->getTitle()->getDBkey(),
 273                         'params' => $this->getParams()
 274                 ];
 275                 if ( is_array( $info['params'] ) ) {
 276                         // Identical jobs with different "root" jobs should count as duplicates
 277                         unset( $info['params']['rootJobSignature'] );
 278                         unset( $info['params']['rootJobTimestamp'] );
 279                         // Likewise for jobs with different delay times
 280                         unset( $info['params']['jobReleaseTimestamp'] );
 281                         // Identical jobs from different requests should count as duplicates
 282                         unset( $info['params']['requestId'] );
 283                         // Queues pack and hash this array, so normalize the order
 284                         ksort( $info['params'] );
 285                 }
 286
 287                 return $info;
 288         }
 289
 290         /**
 291          * Get "root job" parameters for a task
 292          *
 293          * This is used to no-op redundant jobs, including child jobs of jobs,
 294          * as long as the children inherit the root job parameters. When a job
 295          * with root job parameters and "rootJobIsSelf" set is pushed, the
 296          * deduplicateRootJob() method is automatically called on it. If the
 297          * root job is only virtual and not actually pushed (e.g. the sub-jobs
 298          * are inserted directly), then call deduplicateRootJob() directly.
 299          *
 300          * @see JobQueue::deduplicateRootJob()
 301          *
 302          * @param string $key A key that identifies the task
 303          * @return array Map of:
 304          *   - rootJobIsSelf    : true
 305          *   - rootJobSignature : hash (e.g. SHA1) that identifies the task
 306          *   - rootJobTimestamp : TS_MW timestamp of this instance of the task
 307          * @since 1.21
 308          */
 309         public static function newRootJobParams( $key ) {
 310                 return [
 311                         'rootJobIsSelf'    => true,
 312                         'rootJobSignature' => sha1( $key ),
 313                         'rootJobTimestamp' => wfTimestampNow()
 314                 ];
 315         }
 316
 317         /**
 318          * @see JobQueue::deduplicateRootJob()
 319          * @return array
 320          * @since 1.21
 321          */
 322         public function getRootJobParams() {
 323                 return [
 324                         'rootJobSignature' => $this->params['rootJobSignature'] ?? null,
 325                         'rootJobTimestamp' => $this->params['rootJobTimestamp'] ?? null
 326                 ];
 327         }
 328
 329         /**
 330          * @see JobQueue::deduplicateRootJob()
 331          * @return bool
 332          * @since 1.22
 333          */
 334         public function hasRootJobParams() {
 335                 return isset( $this->params['rootJobSignature'] )
 336                         && isset( $this->params['rootJobTimestamp'] );
 337         }
 338
 339         /**
 340          * @see JobQueue::deduplicateRootJob()
 341          * @return bool Whether this is job is a root job
 342          */
 343         public function isRootJob() {
 344                 return $this->hasRootJobParams() && !empty( $this->params['rootJobIsSelf'] );
 345         }
 346
 347         /**
 348          * @param callable $callback A function with one parameter, the success status, which will be
 349          *   false if the job failed or it succeeded but the DB changes could not be committed or
 350          *   any deferred updates threw an exception. (This parameter was added in 1.28.)
 351          * @since 1.27
 352          */
 353         protected function addTeardownCallback( $callback ) {
 354                 $this->teardownCallbacks[] = $callback;
 355         }
 356
 357         /**
 358          * Do any final cleanup after run(), deferred updates, and all DB commits happen
 359          * @param bool $status Whether the job, its deferred updates, and DB commit all succeeded
 360          * @since 1.27
 361          */
 362         public function teardown( $status ) {
 363                 foreach ( $this->teardownCallbacks as $callback ) {
 364                         call_user_func( $callback, $status );
 365                 }
 366         }
 367
 368         /**
 369          * @return string
 370          */
 371         public function toString() {
 372                 $paramString = '';
 373                 if ( $this->params ) {
 374                         foreach ( $this->params as $key => $value ) {
 375                                 if ( $paramString != '' ) {
 376                                         $paramString .= ' ';
 377                                 }
 378                                 if ( is_array( $value ) ) {
 379                                         $filteredValue = [];
 380                                         foreach ( $value as $k => $v ) {
 381                                                 $json = FormatJson::encode( $v );
 382                                                 if ( $json === false || mb_strlen( $json ) > 512 ) {
 383                                                         $filteredValue[$k] = gettype( $v ) . '(...)';
 384                                                 } else {
 385                                                         $filteredValue[$k] = $v;
 386                                                 }
 387                                         }
 388                                         if ( count( $filteredValue ) <= 10 ) {
 389                                                 $value = FormatJson::encode( $filteredValue );
 390                                         } else {
 391                                                 $value = "array(" . count( $value ) . ")";
 392                                         }
 393                                 } elseif ( is_object( $value ) && !method_exists( $value, '__toString' ) ) {
 394                                         $value = "object(" . get_class( $value ) . ")";
 395                                 }
 396
 397                                 $flatValue = (string)$value;
 398                                 if ( mb_strlen( $value ) > 1024 ) {
 399                                         $flatValue = "string(" . mb_strlen( $value ) . ")";
 400                                 }
 401
 402                                 $paramString .= "$key={$flatValue}";
 403                         }
 404                 }
 405
 406                 $metaString = '';
 407                 foreach ( $this->metadata as $key => $value ) {
 408                         if ( is_scalar( $value ) && mb_strlen( $value ) < 1024 ) {
 409                                 $metaString .= ( $metaString ? ",$key=$value" : "$key=$value" );
 410                         }
 411                 }
 412
 413                 $s = $this->command;
 414                 if ( is_object( $this->title ) ) {
 415                         $s .= " {$this->title->getPrefixedDBkey()}";
 416                 }
 417                 if ( $paramString != '' ) {
 418                         $s .= " $paramString";
 419                 }
 420                 if ( $metaString != '' ) {
 421                         $s .= " ($metaString)";
 422                 }
 423
 424                 return $s;
 425         }
 426
 427         protected function setLastError( $error ) {
 428                 $this->error = $error;
 429         }
 430
 431         public function getLastError() {
 432                 return $this->error;
 433         }
 434 }