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                         $handler = $wgJobClasses[$command];
  73
  74                         if ( is_callable( $handler ) ) {
  75                                 $job = call_user_func( $handler, $title, $params );
  76                         } elseif ( class_exists( $handler ) ) {
  77                                 $job = new $handler( $title, $params );
  78                         } else {
  79                                 $job = null;
  80                         }
  81
  82                         if ( $job instanceof Job ) {
  83                                 $job->command = $command;
  84                                 return $job;
  85                         } else {
  86                                 throw new InvalidArgumentException( "Cannot instantiate job '$command': bad spec!" );
  87                         }
  88                 }
  89
  90                 throw new InvalidArgumentException( "Invalid job command '{$command}'" );
  91         }
  92
  93         /**
  94          * @param string $command
  95          * @param Title $title
  96          * @param array|bool $params Can not be === true
  97          */
  98         public function __construct( $command, $title, $params = false ) {
  99                 $this->command = $command;
 100                 $this->title = $title;
 101                 $this->params = is_array( $params ) ? $params : []; // sanity
 102
 103                 // expensive jobs may set this to true
 104                 $this->removeDuplicates = false;
 105
 106                 if ( !isset( $this->params['requestId'] ) ) {
 107                         $this->params['requestId'] = WebRequest::getRequestId();
 108                 }
 109         }
 110
 111         /**
 112          * Batch-insert a group of jobs into the queue.
 113          * This will be wrapped in a transaction with a forced commit.
 114          *
 115          * This may add duplicate at insert time, but they will be
 116          * removed later on, when the first one is popped.
 117          *
 118          * @param Job[] $jobs Array of Job objects
 119          * @return bool
 120          * @deprecated since 1.21
 121          */
 122         public static function batchInsert( $jobs ) {
 123                 wfDeprecated( __METHOD__, '1.21' );
 124                 JobQueueGroup::singleton()->push( $jobs );
 125                 return true;
 126         }
 127
 128         /**
 129          * @return string
 130          */
 131         public function getType() {
 132                 return $this->command;
 133         }
 134
 135         /**
 136          * @return Title
 137          */
 138         public function getTitle() {
 139                 return $this->title;
 140         }
 141
 142         /**
 143          * @return array
 144          */
 145         public function getParams() {
 146                 return $this->params;
 147         }
 148
 149         /**
 150          * @return int|null UNIX timestamp to delay running this job until, otherwise null
 151          * @since 1.22
 152          */
 153         public function getReleaseTimestamp() {
 154                 return isset( $this->params['jobReleaseTimestamp'] )
 155                         ? wfTimestampOrNull( TS_UNIX, $this->params['jobReleaseTimestamp'] )
 156                         : null;
 157         }
 158
 159         /**
 160          * @return int|null UNIX timestamp of when the job was queued, or null
 161          * @since 1.26
 162          */
 163         public function getQueuedTimestamp() {
 164                 return isset( $this->metadata['timestamp'] )
 165                         ? wfTimestampOrNull( TS_UNIX, $this->metadata['timestamp'] )
 166                         : null;
 167         }
 168
 169         /**
 170          * @return string|null Id of the request that created this job. Follows
 171          *  jobs recursively, allowing to track the id of the request that started a
 172          *  job when jobs insert jobs which insert other jobs.
 173          * @since 1.27
 174          */
 175         public function getRequestId() {
 176                 return isset( $this->params['requestId'] )
 177                         ? $this->params['requestId']
 178                         : null;
 179         }
 180
 181         /**
 182          * @return int|null UNIX timestamp of when the job was runnable, or null
 183          * @since 1.26
 184          */
 185         public function getReadyTimestamp() {
 186                 return $this->getReleaseTimestamp() ?: $this->getQueuedTimestamp();
 187         }
 188
 189         /**
 190          * Whether the queue should reject insertion of this job if a duplicate exists
 191          *
 192          * This can be used to avoid duplicated effort or combined with delayed jobs to
 193          * coalesce updates into larger batches. Claimed jobs are never treated as
 194          * duplicates of new jobs, and some queues may allow a few duplicates due to
 195          * network partitions and fail-over. Thus, additional locking is needed to
 196          * enforce mutual exclusion if this is really needed.
 197          *
 198          * @return bool
 199          */
 200         public function ignoreDuplicates() {
 201                 return $this->removeDuplicates;
 202         }
 203
 204         /**
 205          * @return bool Whether this job can be retried on failure by job runners
 206          * @since 1.21
 207          */
 208         public function allowRetries() {
 209                 return true;
 210         }
 211
 212         /**
 213          * @return int Number of actually "work items" handled in this job
 214          * @see $wgJobBackoffThrottling
 215          * @since 1.23
 216          */
 217         public function workItemCount() {
 218                 return 1;
 219         }
 220
 221         /**
 222          * Subclasses may need to override this to make duplication detection work.
 223          * The resulting map conveys everything that makes the job unique. This is
 224          * only checked if ignoreDuplicates() returns true, meaning that duplicate
 225          * jobs are supposed to be ignored.
 226          *
 227          * @return array Map of key/values
 228          * @since 1.21
 229          */
 230         public function getDeduplicationInfo() {
 231                 $info = [
 232                         'type' => $this->getType(),
 233                         'namespace' => $this->getTitle()->getNamespace(),
 234                         'title' => $this->getTitle()->getDBkey(),
 235                         'params' => $this->getParams()
 236                 ];
 237                 if ( is_array( $info['params'] ) ) {
 238                         // Identical jobs with different "root" jobs should count as duplicates
 239                         unset( $info['params']['rootJobSignature'] );
 240                         unset( $info['params']['rootJobTimestamp'] );
 241                         // Likewise for jobs with different delay times
 242                         unset( $info['params']['jobReleaseTimestamp'] );
 243                         // Identical jobs from different requests should count as duplicates
 244                         unset( $info['params']['requestId'] );
 245                         // Queues pack and hash this array, so normalize the order
 246                         ksort( $info['params'] );
 247                 }
 248
 249                 return $info;
 250         }
 251
 252         /**
 253          * Get "root job" parameters for a task
 254          *
 255          * This is used to no-op redundant jobs, including child jobs of jobs,
 256          * as long as the children inherit the root job parameters. When a job
 257          * with root job parameters and "rootJobIsSelf" set is pushed, the
 258          * deduplicateRootJob() method is automatically called on it. If the
 259          * root job is only virtual and not actually pushed (e.g. the sub-jobs
 260          * are inserted directly), then call deduplicateRootJob() directly.
 261          *
 262          * @see JobQueue::deduplicateRootJob()
 263          *
 264          * @param string $key A key that identifies the task
 265          * @return array Map of:
 266          *   - rootJobIsSelf    : true
 267          *   - rootJobSignature : hash (e.g. SHA1) that identifies the task
 268          *   - rootJobTimestamp : TS_MW timestamp of this instance of the task
 269          * @since 1.21
 270          */
 271         public static function newRootJobParams( $key ) {
 272                 return [
 273                         'rootJobIsSelf'    => true,
 274                         'rootJobSignature' => sha1( $key ),
 275                         'rootJobTimestamp' => wfTimestampNow()
 276                 ];
 277         }
 278
 279         /**
 280          * @see JobQueue::deduplicateRootJob()
 281          * @return array
 282          * @since 1.21
 283          */
 284         public function getRootJobParams() {
 285                 return [
 286                         'rootJobSignature' => isset( $this->params['rootJobSignature'] )
 287                                 ? $this->params['rootJobSignature']
 288                                 : null,
 289                         'rootJobTimestamp' => isset( $this->params['rootJobTimestamp'] )
 290                                 ? $this->params['rootJobTimestamp']
 291                                 : null
 292                 ];
 293         }
 294
 295         /**
 296          * @see JobQueue::deduplicateRootJob()
 297          * @return bool
 298          * @since 1.22
 299          */
 300         public function hasRootJobParams() {
 301                 return isset( $this->params['rootJobSignature'] )
 302                         && isset( $this->params['rootJobTimestamp'] );
 303         }
 304
 305         /**
 306          * @see JobQueue::deduplicateRootJob()
 307          * @return bool Whether this is job is a root job
 308          */
 309         public function isRootJob() {
 310                 return $this->hasRootJobParams() && !empty( $this->params['rootJobIsSelf'] );
 311         }
 312
 313         /**
 314          * @param callable $callback A function with one parameter, the success status, which will be
 315          *   false if the job failed or it succeeded but the DB changes could not be committed or
 316          *   any deferred updates threw an exception. (This parameter was added in 1.28.)
 317          * @since 1.27
 318          */
 319         protected function addTeardownCallback( $callback ) {
 320                 $this->teardownCallbacks[] = $callback;
 321         }
 322
 323         /**
 324          * Do any final cleanup after run(), deferred updates, and all DB commits happen
 325          * @param bool $status Whether the job, its deferred updates, and DB commit all succeeded
 326          * @since 1.27
 327          */
 328         public function teardown( $status ) {
 329                 foreach ( $this->teardownCallbacks as $callback ) {
 330                         call_user_func( $callback, $status );
 331                 }
 332         }
 333
 334         /**
 335          * Insert a single job into the queue.
 336          * @return bool True on success
 337          * @deprecated since 1.21
 338          */
 339         public function insert() {
 340                 JobQueueGroup::singleton()->push( $this );
 341                 return true;
 342         }
 343
 344         /**
 345          * @return string
 346          */
 347         public function toString() {
 348                 $paramString = '';
 349                 if ( $this->params ) {
 350                         foreach ( $this->params as $key => $value ) {
 351                                 if ( $paramString != '' ) {
 352                                         $paramString .= ' ';
 353                                 }
 354                                 if ( is_array( $value ) ) {
 355                                         $filteredValue = [];
 356                                         foreach ( $value as $k => $v ) {
 357                                                 $json = FormatJson::encode( $v );
 358                                                 if ( $json === false || mb_strlen( $json ) > 512 ) {
 359                                                         $filteredValue[$k] = gettype( $v ) . '(...)';
 360                                                 } else {
 361                                                         $filteredValue[$k] = $v;
 362                                                 }
 363                                         }
 364                                         if ( count( $filteredValue ) <= 10 ) {
 365                                                 $value = FormatJson::encode( $filteredValue );
 366                                         } else {
 367                                                 $value = "array(" . count( $value ) . ")";
 368                                         }
 369                                 } elseif ( is_object( $value ) && !method_exists( $value, '__toString' ) ) {
 370                                         $value = "object(" . get_class( $value ) . ")";
 371                                 }
 372
 373                                 $flatValue = (string)$value;
 374                                 if ( mb_strlen( $value ) > 1024 ) {
 375                                         $flatValue = "string(" . mb_strlen( $value ) . ")";
 376                                 }
 377
 378                                 $paramString .= "$key={$flatValue}";
 379                         }
 380                 }
 381
 382                 $metaString = '';
 383                 foreach ( $this->metadata as $key => $value ) {
 384                         if ( is_scalar( $value ) && mb_strlen( $value ) < 1024 ) {
 385                                 $metaString .= ( $metaString ? ",$key=$value" : "$key=$value" );
 386                         }
 387                 }
 388
 389                 $s = $this->command;
 390                 if ( is_object( $this->title ) ) {
 391                         $s .= " {$this->title->getPrefixedDBkey()}";
 392                 }
 393                 if ( $paramString != '' ) {
 394                         $s .= " $paramString";
 395                 }
 396                 if ( $metaString != '' ) {
 397                         $s .= " ($metaString)";
 398                 }
 399
 400                 return $s;
 401         }
 402
 403         protected function setLastError( $error ) {
 404                 $this->error = $error;
 405         }
 406
 407         public function getLastError() {
 408                 return $this->error;
 409         }
 410 }