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 $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 $params
 110          */
 111         public function __construct( $command, $params = [] ) {
 112                 if ( $params instanceof Title ) {
 113                         // Backwards compatibility for old signature ($command, $title, $params)
 114                         $title = $params;
 115                         $params = func_num_args() >= 3 ? 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 : []; // sanity
 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          * @return int|null UNIX timestamp to delay running this job until, otherwise null
 161          * @since 1.22
 162          */
 163         public function getReleaseTimestamp() {
 164                 return isset( $this->params['jobReleaseTimestamp'] )
 165                         ? wfTimestampOrNull( TS_UNIX, $this->params['jobReleaseTimestamp'] )
 166                         : null;
 167         }
 168
 169         /**
 170          * @return int|null UNIX timestamp of when the job was queued, or null
 171          * @since 1.26
 172          */
 173         public function getQueuedTimestamp() {
 174                 return isset( $this->metadata['timestamp'] )
 175                         ? wfTimestampOrNull( TS_UNIX, $this->metadata['timestamp'] )
 176                         : null;
 177         }
 178
 179         /**
 180          * @return string|null Id of the request that created this job. Follows
 181          *  jobs recursively, allowing to track the id of the request that started a
 182          *  job when jobs insert jobs which insert other jobs.
 183          * @since 1.27
 184          */
 185         public function getRequestId() {
 186                 return $this->params['requestId'] ?? null;
 187         }
 188
 189         /**
 190          * @return int|null UNIX timestamp of when the job was runnable, or null
 191          * @since 1.26
 192          */
 193         public function getReadyTimestamp() {
 194                 return $this->getReleaseTimestamp() ?: $this->getQueuedTimestamp();
 195         }
 196
 197         /**
 198          * Whether the queue should reject insertion of this job if a duplicate exists
 199          *
 200          * This can be used to avoid duplicated effort or combined with delayed jobs to
 201          * coalesce updates into larger batches. Claimed jobs are never treated as
 202          * duplicates of new jobs, and some queues may allow a few duplicates due to
 203          * network partitions and fail-over. Thus, additional locking is needed to
 204          * enforce mutual exclusion if this is really needed.
 205          *
 206          * @return bool
 207          */
 208         public function ignoreDuplicates() {
 209                 return $this->removeDuplicates;
 210         }
 211
 212         /**
 213          * @return bool Whether this job can be retried on failure by job runners
 214          * @since 1.21
 215          */
 216         public function allowRetries() {
 217                 return true;
 218         }
 219
 220         /**
 221          * @return int Number of actually "work items" handled in this job
 222          * @see $wgJobBackoffThrottling
 223          * @since 1.23
 224          */
 225         public function workItemCount() {
 226                 return 1;
 227         }
 228
 229         /**
 230          * Subclasses may need to override this to make duplication detection work.
 231          * The resulting map conveys everything that makes the job unique. This is
 232          * only checked if ignoreDuplicates() returns true, meaning that duplicate
 233          * jobs are supposed to be ignored.
 234          *
 235          * @return array Map of key/values
 236          * @since 1.21
 237          */
 238         public function getDeduplicationInfo() {
 239                 $info = [
 240                         'type' => $this->getType(),
 241                         'namespace' => $this->getTitle()->getNamespace(),
 242                         'title' => $this->getTitle()->getDBkey(),
 243                         'params' => $this->getParams()
 244                 ];
 245                 if ( is_array( $info['params'] ) ) {
 246                         // Identical jobs with different "root" jobs should count as duplicates
 247                         unset( $info['params']['rootJobSignature'] );
 248                         unset( $info['params']['rootJobTimestamp'] );
 249                         // Likewise for jobs with different delay times
 250                         unset( $info['params']['jobReleaseTimestamp'] );
 251                         // Identical jobs from different requests should count as duplicates
 252                         unset( $info['params']['requestId'] );
 253                         // Queues pack and hash this array, so normalize the order
 254                         ksort( $info['params'] );
 255                 }
 256
 257                 return $info;
 258         }
 259
 260         /**
 261          * Get "root job" parameters for a task
 262          *
 263          * This is used to no-op redundant jobs, including child jobs of jobs,
 264          * as long as the children inherit the root job parameters. When a job
 265          * with root job parameters and "rootJobIsSelf" set is pushed, the
 266          * deduplicateRootJob() method is automatically called on it. If the
 267          * root job is only virtual and not actually pushed (e.g. the sub-jobs
 268          * are inserted directly), then call deduplicateRootJob() directly.
 269          *
 270          * @see JobQueue::deduplicateRootJob()
 271          *
 272          * @param string $key A key that identifies the task
 273          * @return array Map of:
 274          *   - rootJobIsSelf    : true
 275          *   - rootJobSignature : hash (e.g. SHA1) that identifies the task
 276          *   - rootJobTimestamp : TS_MW timestamp of this instance of the task
 277          * @since 1.21
 278          */
 279         public static function newRootJobParams( $key ) {
 280                 return [
 281                         'rootJobIsSelf'    => true,
 282                         'rootJobSignature' => sha1( $key ),
 283                         'rootJobTimestamp' => wfTimestampNow()
 284                 ];
 285         }
 286
 287         /**
 288          * @see JobQueue::deduplicateRootJob()
 289          * @return array
 290          * @since 1.21
 291          */
 292         public function getRootJobParams() {
 293                 return [
 294                         'rootJobSignature' => $this->params['rootJobSignature'] ?? null,
 295                         'rootJobTimestamp' => $this->params['rootJobTimestamp'] ?? null
 296                 ];
 297         }
 298
 299         /**
 300          * @see JobQueue::deduplicateRootJob()
 301          * @return bool
 302          * @since 1.22
 303          */
 304         public function hasRootJobParams() {
 305                 return isset( $this->params['rootJobSignature'] )
 306                         && isset( $this->params['rootJobTimestamp'] );
 307         }
 308
 309         /**
 310          * @see JobQueue::deduplicateRootJob()
 311          * @return bool Whether this is job is a root job
 312          */
 313         public function isRootJob() {
 314                 return $this->hasRootJobParams() && !empty( $this->params['rootJobIsSelf'] );
 315         }
 316
 317         /**
 318          * @param callable $callback A function with one parameter, the success status, which will be
 319          *   false if the job failed or it succeeded but the DB changes could not be committed or
 320          *   any deferred updates threw an exception. (This parameter was added in 1.28.)
 321          * @since 1.27
 322          */
 323         protected function addTeardownCallback( $callback ) {
 324                 $this->teardownCallbacks[] = $callback;
 325         }
 326
 327         /**
 328          * Do any final cleanup after run(), deferred updates, and all DB commits happen
 329          * @param bool $status Whether the job, its deferred updates, and DB commit all succeeded
 330          * @since 1.27
 331          */
 332         public function teardown( $status ) {
 333                 foreach ( $this->teardownCallbacks as $callback ) {
 334                         call_user_func( $callback, $status );
 335                 }
 336         }
 337
 338         /**
 339          * @return string
 340          */
 341         public function toString() {
 342                 $paramString = '';
 343                 if ( $this->params ) {
 344                         foreach ( $this->params as $key => $value ) {
 345                                 if ( $paramString != '' ) {
 346                                         $paramString .= ' ';
 347                                 }
 348                                 if ( is_array( $value ) ) {
 349                                         $filteredValue = [];
 350                                         foreach ( $value as $k => $v ) {
 351                                                 $json = FormatJson::encode( $v );
 352                                                 if ( $json === false || mb_strlen( $json ) > 512 ) {
 353                                                         $filteredValue[$k] = gettype( $v ) . '(...)';
 354                                                 } else {
 355                                                         $filteredValue[$k] = $v;
 356                                                 }
 357                                         }
 358                                         if ( count( $filteredValue ) <= 10 ) {
 359                                                 $value = FormatJson::encode( $filteredValue );
 360                                         } else {
 361                                                 $value = "array(" . count( $value ) . ")";
 362                                         }
 363                                 } elseif ( is_object( $value ) && !method_exists( $value, '__toString' ) ) {
 364                                         $value = "object(" . get_class( $value ) . ")";
 365                                 }
 366
 367                                 $flatValue = (string)$value;
 368                                 if ( mb_strlen( $value ) > 1024 ) {
 369                                         $flatValue = "string(" . mb_strlen( $value ) . ")";
 370                                 }
 371
 372                                 $paramString .= "$key={$flatValue}";
 373                         }
 374                 }
 375
 376                 $metaString = '';
 377                 foreach ( $this->metadata as $key => $value ) {
 378                         if ( is_scalar( $value ) && mb_strlen( $value ) < 1024 ) {
 379                                 $metaString .= ( $metaString ? ",$key=$value" : "$key=$value" );
 380                         }
 381                 }
 382
 383                 $s = $this->command;
 384                 if ( is_object( $this->title ) ) {
 385                         $s .= " {$this->title->getPrefixedDBkey()}";
 386                 }
 387                 if ( $paramString != '' ) {
 388                         $s .= " $paramString";
 389                 }
 390                 if ( $metaString != '' ) {
 391                         $s .= " ($metaString)";
 392                 }
 393
 394                 return $s;
 395         }
 396
 397         protected function setLastError( $error ) {
 398                 $this->error = $error;
 399         }
 400
 401         public function getLastError() {
 402                 return $this->error;
 403         }
 404 }