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         /** @var int Bitfield of JOB_* class constants */
  54         protected $executionFlags = 0;
  55
  56         /** @var int Job must not be wrapped in the usual explicit LBFactory transaction round */
  57         const JOB_NO_EXPLICIT_TRX_ROUND = 1;
  58
  59         /**
  60          * Run the job
  61          * @return bool Success
  62          */
  63         abstract public function run();
  64
  65         /**
  66          * Create the appropriate object to handle a specific job
  67          *
  68          * @param string $command Job command
  69          * @param Title $title Associated title
  70          * @param array $params Job parameters
  71          * @throws MWException
  72          * @return Job
  73          */
  74         public static function factory( $command, Title $title, $params = [] ) {
  75                 global $wgJobClasses;
  76
  77                 if ( isset( $wgJobClasses[$command] ) ) {
  78                         $handler = $wgJobClasses[$command];
  79
  80                         if ( is_callable( $handler ) ) {
  81                                 $job = call_user_func( $handler, $title, $params );
  82                         } elseif ( class_exists( $handler ) ) {
  83                                 $job = new $handler( $title, $params );
  84                         } else {
  85                                 $job = null;
  86                         }
  87
  88                         if ( $job instanceof Job ) {
  89                                 $job->command = $command;
  90                                 return $job;
  91                         } else {
  92                                 throw new InvalidArgumentException( "Cannot instantiate job '$command': bad spec!" );
  93                         }
  94                 }
  95
  96                 throw new InvalidArgumentException( "Invalid job command '{$command}'" );
  97         }
  98
  99         /**
 100          * @param string $command
 101          * @param Title $title
 102          * @param array|bool $params Can not be === true
 103          */
 104         public function __construct( $command, $title, $params = false ) {
 105                 $this->command = $command;
 106                 $this->title = $title;
 107                 $this->params = is_array( $params ) ? $params : []; // sanity
 108
 109                 // expensive jobs may set this to true
 110                 $this->removeDuplicates = false;
 111
 112                 if ( !isset( $this->params['requestId'] ) ) {
 113                         $this->params['requestId'] = WebRequest::getRequestId();
 114                 }
 115         }
 116
 117         /**
 118          * @param int $flag JOB_* class constant
 119          * @return bool
 120          * @since 1.31
 121          */
 122         public function hasExecutionFlag( $flag ) {
 123                 return ( $this->executionFlags && $flag ) === $flag;
 124         }
 125
 126         /**
 127          * Batch-insert a group of jobs into the queue.
 128          * This will be wrapped in a transaction with a forced commit.
 129          *
 130          * This may add duplicate at insert time, but they will be
 131          * removed later on, when the first one is popped.
 132          *
 133          * @param Job[] $jobs Array of Job objects
 134          * @return bool
 135          * @deprecated since 1.21
 136          */
 137         public static function batchInsert( $jobs ) {
 138                 wfDeprecated( __METHOD__, '1.21' );
 139                 JobQueueGroup::singleton()->push( $jobs );
 140                 return true;
 141         }
 142
 143         /**
 144          * @return string
 145          */
 146         public function getType() {
 147                 return $this->command;
 148         }
 149
 150         /**
 151          * @return Title
 152          */
 153         public function getTitle() {
 154                 return $this->title;
 155         }
 156
 157         /**
 158          * @return array
 159          */
 160         public function getParams() {
 161                 return $this->params;
 162         }
 163
 164         /**
 165          * @return int|null UNIX timestamp to delay running this job until, otherwise null
 166          * @since 1.22
 167          */
 168         public function getReleaseTimestamp() {
 169                 return isset( $this->params['jobReleaseTimestamp'] )
 170                         ? wfTimestampOrNull( TS_UNIX, $this->params['jobReleaseTimestamp'] )
 171                         : null;
 172         }
 173
 174         /**
 175          * @return int|null UNIX timestamp of when the job was queued, or null
 176          * @since 1.26
 177          */
 178         public function getQueuedTimestamp() {
 179                 return isset( $this->metadata['timestamp'] )
 180                         ? wfTimestampOrNull( TS_UNIX, $this->metadata['timestamp'] )
 181                         : null;
 182         }
 183
 184         /**
 185          * @return string|null Id of the request that created this job. Follows
 186          *  jobs recursively, allowing to track the id of the request that started a
 187          *  job when jobs insert jobs which insert other jobs.
 188          * @since 1.27
 189          */
 190         public function getRequestId() {
 191                 return isset( $this->params['requestId'] )
 192                         ? $this->params['requestId']
 193                         : null;
 194         }
 195
 196         /**
 197          * @return int|null UNIX timestamp of when the job was runnable, or null
 198          * @since 1.26
 199          */
 200         public function getReadyTimestamp() {
 201                 return $this->getReleaseTimestamp() ?: $this->getQueuedTimestamp();
 202         }
 203
 204         /**
 205          * Whether the queue should reject insertion of this job if a duplicate exists
 206          *
 207          * This can be used to avoid duplicated effort or combined with delayed jobs to
 208          * coalesce updates into larger batches. Claimed jobs are never treated as
 209          * duplicates of new jobs, and some queues may allow a few duplicates due to
 210          * network partitions and fail-over. Thus, additional locking is needed to
 211          * enforce mutual exclusion if this is really needed.
 212          *
 213          * @return bool
 214          */
 215         public function ignoreDuplicates() {
 216                 return $this->removeDuplicates;
 217         }
 218
 219         /**
 220          * @return bool Whether this job can be retried on failure by job runners
 221          * @since 1.21
 222          */
 223         public function allowRetries() {
 224                 return true;
 225         }
 226
 227         /**
 228          * @return int Number of actually "work items" handled in this job
 229          * @see $wgJobBackoffThrottling
 230          * @since 1.23
 231          */
 232         public function workItemCount() {
 233                 return 1;
 234         }
 235
 236         /**
 237          * Subclasses may need to override this to make duplication detection work.
 238          * The resulting map conveys everything that makes the job unique. This is
 239          * only checked if ignoreDuplicates() returns true, meaning that duplicate
 240          * jobs are supposed to be ignored.
 241          *
 242          * @return array Map of key/values
 243          * @since 1.21
 244          */
 245         public function getDeduplicationInfo() {
 246                 $info = [
 247                         'type' => $this->getType(),
 248                         'namespace' => $this->getTitle()->getNamespace(),
 249                         'title' => $this->getTitle()->getDBkey(),
 250                         'params' => $this->getParams()
 251                 ];
 252                 if ( is_array( $info['params'] ) ) {
 253                         // Identical jobs with different "root" jobs should count as duplicates
 254                         unset( $info['params']['rootJobSignature'] );
 255                         unset( $info['params']['rootJobTimestamp'] );
 256                         // Likewise for jobs with different delay times
 257                         unset( $info['params']['jobReleaseTimestamp'] );
 258                         // Identical jobs from different requests should count as duplicates
 259                         unset( $info['params']['requestId'] );
 260                         // Queues pack and hash this array, so normalize the order
 261                         ksort( $info['params'] );
 262                 }
 263
 264                 return $info;
 265         }
 266
 267         /**
 268          * Get "root job" parameters for a task
 269          *
 270          * This is used to no-op redundant jobs, including child jobs of jobs,
 271          * as long as the children inherit the root job parameters. When a job
 272          * with root job parameters and "rootJobIsSelf" set is pushed, the
 273          * deduplicateRootJob() method is automatically called on it. If the
 274          * root job is only virtual and not actually pushed (e.g. the sub-jobs
 275          * are inserted directly), then call deduplicateRootJob() directly.
 276          *
 277          * @see JobQueue::deduplicateRootJob()
 278          *
 279          * @param string $key A key that identifies the task
 280          * @return array Map of:
 281          *   - rootJobIsSelf    : true
 282          *   - rootJobSignature : hash (e.g. SHA1) that identifies the task
 283          *   - rootJobTimestamp : TS_MW timestamp of this instance of the task
 284          * @since 1.21
 285          */
 286         public static function newRootJobParams( $key ) {
 287                 return [
 288                         'rootJobIsSelf'    => true,
 289                         'rootJobSignature' => sha1( $key ),
 290                         'rootJobTimestamp' => wfTimestampNow()
 291                 ];
 292         }
 293
 294         /**
 295          * @see JobQueue::deduplicateRootJob()
 296          * @return array
 297          * @since 1.21
 298          */
 299         public function getRootJobParams() {
 300                 return [
 301                         'rootJobSignature' => isset( $this->params['rootJobSignature'] )
 302                                 ? $this->params['rootJobSignature']
 303                                 : null,
 304                         'rootJobTimestamp' => isset( $this->params['rootJobTimestamp'] )
 305                                 ? $this->params['rootJobTimestamp']
 306                                 : null
 307                 ];
 308         }
 309
 310         /**
 311          * @see JobQueue::deduplicateRootJob()
 312          * @return bool
 313          * @since 1.22
 314          */
 315         public function hasRootJobParams() {
 316                 return isset( $this->params['rootJobSignature'] )
 317                         && isset( $this->params['rootJobTimestamp'] );
 318         }
 319
 320         /**
 321          * @see JobQueue::deduplicateRootJob()
 322          * @return bool Whether this is job is a root job
 323          */
 324         public function isRootJob() {
 325                 return $this->hasRootJobParams() && !empty( $this->params['rootJobIsSelf'] );
 326         }
 327
 328         /**
 329          * @param callable $callback A function with one parameter, the success status, which will be
 330          *   false if the job failed or it succeeded but the DB changes could not be committed or
 331          *   any deferred updates threw an exception. (This parameter was added in 1.28.)
 332          * @since 1.27
 333          */
 334         protected function addTeardownCallback( $callback ) {
 335                 $this->teardownCallbacks[] = $callback;
 336         }
 337
 338         /**
 339          * Do any final cleanup after run(), deferred updates, and all DB commits happen
 340          * @param bool $status Whether the job, its deferred updates, and DB commit all succeeded
 341          * @since 1.27
 342          */
 343         public function teardown( $status ) {
 344                 foreach ( $this->teardownCallbacks as $callback ) {
 345                         call_user_func( $callback, $status );
 346                 }
 347         }
 348
 349         /**
 350          * Insert a single job into the queue.
 351          * @return bool True on success
 352          * @deprecated since 1.21
 353          */
 354         public function insert() {
 355                 wfDeprecated( __METHOD__, '1.21' );
 356                 JobQueueGroup::singleton()->push( $this );
 357                 return true;
 358         }
 359
 360         /**
 361          * @return string
 362          */
 363         public function toString() {
 364                 $paramString = '';
 365                 if ( $this->params ) {
 366                         foreach ( $this->params as $key => $value ) {
 367                                 if ( $paramString != '' ) {
 368                                         $paramString .= ' ';
 369                                 }
 370                                 if ( is_array( $value ) ) {
 371                                         $filteredValue = [];
 372                                         foreach ( $value as $k => $v ) {
 373                                                 $json = FormatJson::encode( $v );
 374                                                 if ( $json === false || mb_strlen( $json ) > 512 ) {
 375                                                         $filteredValue[$k] = gettype( $v ) . '(...)';
 376                                                 } else {
 377                                                         $filteredValue[$k] = $v;
 378                                                 }
 379                                         }
 380                                         if ( count( $filteredValue ) <= 10 ) {
 381                                                 $value = FormatJson::encode( $filteredValue );
 382                                         } else {
 383                                                 $value = "array(" . count( $value ) . ")";
 384                                         }
 385                                 } elseif ( is_object( $value ) && !method_exists( $value, '__toString' ) ) {
 386                                         $value = "object(" . get_class( $value ) . ")";
 387                                 }
 388
 389                                 $flatValue = (string)$value;
 390                                 if ( mb_strlen( $value ) > 1024 ) {
 391                                         $flatValue = "string(" . mb_strlen( $value ) . ")";
 392                                 }
 393
 394                                 $paramString .= "$key={$flatValue}";
 395                         }
 396                 }
 397
 398                 $metaString = '';
 399                 foreach ( $this->metadata as $key => $value ) {
 400                         if ( is_scalar( $value ) && mb_strlen( $value ) < 1024 ) {
 401                                 $metaString .= ( $metaString ? ",$key=$value" : "$key=$value" );
 402                         }
 403                 }
 404
 405                 $s = $this->command;
 406                 if ( is_object( $this->title ) ) {
 407                         $s .= " {$this->title->getPrefixedDBkey()}";
 408                 }
 409                 if ( $paramString != '' ) {
 410                         $s .= " $paramString";
 411                 }
 412                 if ( $metaString != '' ) {
 413                         $s .= " ($metaString)";
 414                 }
 415
 416                 return $s;
 417         }
 418
 419         protected function setLastError( $error ) {
 420                 $this->error = $error;
 421         }
 422
 423         public function getLastError() {
 424                 return $this->error;
 425         }
 426 }