includes/JobQueue.php

   1 <?php
   2
   3 if ( !defined( 'MEDIAWIKI' ) ) {
   4         die( "This file is part of MediaWiki, it is not a valid entry point\n" );
   5 }
   6
   7 require_once('UserMailer.php');
   8
   9 /**
  10  * Class to both describe a background job and handle jobs.
  11  */
  12 abstract class Job {
  13         var $command,
  14                 $title,
  15                 $params,
  16                 $id,
  17                 $removeDuplicates,
  18                 $error;
  19
  20         /*-------------------------------------------------------------------------
  21          * Abstract functions
  22          *------------------------------------------------------------------------*/
  23
  24         /**
  25          * Run the job
  26          * @return boolean success
  27          */
  28         abstract function run();
  29
  30         /*-------------------------------------------------------------------------
  31          * Static functions
  32          *------------------------------------------------------------------------*/
  33
  34         /**
  35          * @deprecated use LinksUpdate::queueRecursiveJobs()
  36          */
  37         /**
  38          * static function queueLinksJobs( $titles ) {}
  39          */
  40
  41         /**
  42          * Pop a job of a certain type.  This tries less hard than pop() to
  43          * actually find a job; it may be adversely affected by concurrent job
  44          * runners.
  45          */
  46         static function pop_type($type) {
  47                 wfProfilein( __METHOD__ );
  48
  49                 $dbw = wfGetDB( DB_MASTER );
  50
  51
  52                 $row = $dbw->selectRow( 'job', '*', array( 'job_cmd' => $type ), __METHOD__,
  53                                 array( 'LIMIT' => 1 ));
  54
  55                 if ($row === false) {
  56                         wfProfileOut( __METHOD__ );
  57                         return false;
  58                 }
  59
  60                 /* Ensure we "own" this row */
  61                 $dbw->delete( 'job', array( 'job_id' => $row->job_id ), __METHOD__ );
  62                 $affected = $dbw->affectedRows();
  63
  64                 if ($affected == 0) {
  65                         wfProfileOut( __METHOD__ );
  66                         return false;
  67                 }
  68
  69                 $namespace = $row->job_namespace;
  70                 $dbkey = $row->job_title;
  71                 $title = Title::makeTitleSafe( $namespace, $dbkey );
  72                 $job = Job::factory( $row->job_cmd, $title, Job::extractBlob( $row->job_params ), $row->job_id );
  73
  74                 $dbw->delete( 'job', $job->insertFields(), __METHOD__ );
  75                 $dbw->immediateCommit();
  76
  77                 wfProfileOut( __METHOD__ );
  78                 return $job;
  79         }
  80
  81         /**
  82          * Pop a job off the front of the queue
  83          * @static
  84          * @param $offset Number of jobs to skip
  85          * @return Job or false if there's no jobs
  86          */
  87         static function pop($offset=0) {
  88                 wfProfileIn( __METHOD__ );
  89
  90                 $dbr = wfGetDB( DB_SLAVE );
  91
  92                 /* Get a job from the slave, start with an offset,
  93                         scan full set afterwards, avoid hitting purged rows
  94
  95                         NB: If random fetch previously was used, offset
  96                                 will always be ahead of few entries
  97                 */
  98
  99                 $row = $dbr->selectRow( 'job', '*', "job_id >= ${offset}", __METHOD__,
 100                         array( 'ORDER BY' => 'job_id', 'LIMIT' => 1 ));
 101
 102                 // Refetching without offset is needed as some of job IDs could have had delayed commits
 103                 // and have lower IDs than jobs already executed, blame concurrency :)
 104                 //
 105                 if ( $row === false) {
 106                         if ($offset!=0)
 107                                 $row = $dbr->selectRow( 'job', '*', '', __METHOD__,
 108                                         array( 'ORDER BY' => 'job_id', 'LIMIT' => 1 ));
 109
 110                         if ($row === false ) {
 111                                 wfProfileOut( __METHOD__ );
 112                                 return false;
 113                         }
 114                 }
 115                 $offset = $row->job_id;
 116
 117                 // Try to delete it from the master
 118                 $dbw = wfGetDB( DB_MASTER );
 119                 $dbw->delete( 'job', array( 'job_id' => $row->job_id ), __METHOD__ );
 120                 $affected = $dbw->affectedRows();
 121                 $dbw->immediateCommit();
 122
 123                 if ( !$affected ) {
 124                         // Failed, someone else beat us to it
 125                         // Try getting a random row
 126                         $row = $dbw->selectRow( 'job', array( 'MIN(job_id) as minjob',
 127                                 'MAX(job_id) as maxjob' ), "job_id >= $offset", __METHOD__ );
 128                         if ( $row === false || is_null( $row->minjob ) || is_null( $row->maxjob ) ) {
 129                                 // No jobs to get
 130                                 wfProfileOut( __METHOD__ );
 131                                 return false;
 132                         }
 133                         // Get the random row
 134                         $row = $dbw->selectRow( 'job', '*',
 135                                 'job_id >= ' . mt_rand( $row->minjob, $row->maxjob ),   __METHOD__ );
 136                         if ( $row === false ) {
 137                                 // Random job gone before we got the chance to select it
 138                                 // Give up
 139                                 wfProfileOut( __METHOD__ );
 140                                 return false;
 141                         }
 142                         // Delete the random row
 143                         $dbw->delete( 'job', array( 'job_id' => $row->job_id ), __METHOD__ );
 144                         $affected = $dbw->affectedRows();
 145                         $dbw->immediateCommit();
 146
 147                         if ( !$affected ) {
 148                                 // Random job gone before we exclusively deleted it
 149                                 // Give up
 150                                 wfProfileOut( __METHOD__ );
 151                                 return false;
 152                         }
 153                 }
 154
 155                 // If execution got to here, there's a row in $row that has been deleted from the database
 156                 // by this thread. Hence the concurrent pop was successful.
 157                 $namespace = $row->job_namespace;
 158                 $dbkey = $row->job_title;
 159                 $title = Title::makeTitleSafe( $namespace, $dbkey );
 160                 $job = Job::factory( $row->job_cmd, $title, Job::extractBlob( $row->job_params ), $row->job_id );
 161
 162                 // Remove any duplicates it may have later in the queue
 163                 $dbw->delete( 'job', $job->insertFields(), __METHOD__ );
 164
 165                 wfProfileOut( __METHOD__ );
 166                 return $job;
 167         }
 168
 169         /**
 170          * Create an object of a subclass
 171          */
 172         static function factory( $command, $title, $params = false, $id = 0 ) {
 173                 switch ( $command ) {
 174                         case 'refreshLinks':
 175                                 return new RefreshLinksJob( $title, $params, $id );
 176                         case 'htmlCacheUpdate':
 177                         case 'html_cache_update': # BC
 178                                 return new HTMLCacheUpdateJob( $title, $params['table'], $params['start'], $params['end'], $id );
 179                         case 'sendMail':
 180                                 return new EmaillingJob($params);
 181                         case 'enotifNotify':
 182                                 return new EnotifNotifyJob($title, $params);
 183                         default:
 184                                 throw new MWException( "Invalid job command \"$command\"" );
 185                 }
 186         }
 187
 188         static function makeBlob( $params ) {
 189                 if ( $params !== false ) {
 190                         return serialize( $params );
 191                 } else {
 192                         return '';
 193                 }
 194         }
 195
 196         static function extractBlob( $blob ) {
 197                 if ( (string)$blob !== '' ) {
 198                         return unserialize( $blob );
 199                 } else {
 200                         return false;
 201                 }
 202         }
 203
 204         /**
 205          * Batch-insert a group of jobs into the queue.
 206          * This will be wrapped in a transaction with a forced commit.
 207          *
 208          * This may add duplicate at insert time, but they will be
 209          * removed later on, when the first one is popped.
 210          *
 211          * @param $jobs array of Job objects
 212          */
 213         static function batchInsert( $jobs ) {
 214                 if( count( $jobs ) ) {
 215                         $dbw = wfGetDB( DB_MASTER );
 216                         $dbw->begin();
 217                         foreach( $jobs as $job ) {
 218                                 $rows[] = $job->insertFields();
 219                         }
 220                         $dbw->insert( 'job', $rows, __METHOD__, 'IGNORE' );
 221                         $dbw->commit();
 222                 }
 223         }
 224
 225         /*-------------------------------------------------------------------------
 226          * Non-static functions
 227          *------------------------------------------------------------------------*/
 228
 229         function __construct( $command, $title, $params = false, $id = 0 ) {
 230                 $this->command = $command;
 231                 $this->title = $title;
 232                 $this->params = $params;
 233                 $this->id = $id;
 234
 235                 // A bit of premature generalisation
 236                 // Oh well, the whole class is premature generalisation really
 237                 $this->removeDuplicates = true;
 238         }
 239
 240         /**
 241          * Insert a single job into the queue.
 242          */
 243         function insert() {
 244                 $fields = $this->insertFields();
 245
 246                 $dbw = wfGetDB( DB_MASTER );
 247
 248                 if ( $this->removeDuplicates ) {
 249                         $res = $dbw->select( 'job', array( '1' ), $fields, __METHOD__ );
 250                         if ( $dbw->numRows( $res ) ) {
 251                                 return;
 252                         }
 253                 }
 254                 $fields['job_id'] = $dbw->nextSequenceValue( 'job_job_id_seq' );
 255                 $dbw->insert( 'job', $fields, __METHOD__ );
 256         }
 257
 258         protected function insertFields() {
 259                 return array(
 260                         'job_cmd' => $this->command,
 261                         'job_namespace' => $this->title->getNamespace(),
 262                         'job_title' => $this->title->getDBkey(),
 263                         'job_params' => Job::makeBlob( $this->params )
 264                 );
 265         }
 266
 267         function toString() {
 268                 $paramString = '';
 269                 if ( $this->params ) {
 270                         foreach ( $this->params as $key => $value ) {
 271                                 if ( $paramString != '' ) {
 272                                         $paramString .= ' ';
 273                                 }
 274                                 $paramString .= "$key=$value";
 275                         }
 276                 }
 277
 278                 if ( is_object( $this->title ) ) {
 279                         $s = "{$this->command} " . $this->title->getPrefixedDBkey();
 280                         if ( $paramString !== '' ) {
 281                                 $s .= ' ' . $paramString;
 282                         }
 283                         return $s;
 284                 } else {
 285                         return "{$this->command} $paramString";
 286                 }
 287         }
 288
 289         function getLastError() {
 290                 return $this->error;
 291         }
 292 }
 293
 294
 295 /**
 296  * Background job to update links for a given title.
 297  */
 298 class RefreshLinksJob extends Job {
 299         function __construct( $title, $params = '', $id = 0 ) {
 300                 parent::__construct( 'refreshLinks', $title, $params, $id );
 301         }
 302
 303         /**
 304          * Run a refreshLinks job
 305          * @return boolean success
 306          */
 307         function run() {
 308                 global $wgParser;
 309                 wfProfileIn( __METHOD__ );
 310
 311                 $linkCache =& LinkCache::singleton();
 312                 $linkCache->clear();
 313
 314                 if ( is_null( $this->title ) ) {
 315                         $this->error = "refreshLinks: Invalid title";
 316                         wfProfileOut( __METHOD__ );
 317                         return false;
 318                 }
 319
 320                 $revision = Revision::newFromTitle( $this->title );
 321                 if ( !$revision ) {
 322                         $this->error = 'refreshLinks: Article not found "' . $this->title->getPrefixedDBkey() . '"';
 323                         wfProfileOut( __METHOD__ );
 324                         return false;
 325                 }
 326
 327                 wfProfileIn( __METHOD__.'-parse' );
 328                 $options = new ParserOptions;
 329                 $parserOutput = $wgParser->parse( $revision->getText(), $this->title, $options, true, true, $revision->getId() );
 330                 wfProfileOut( __METHOD__.'-parse' );
 331                 wfProfileIn( __METHOD__.'-update' );
 332                 $update = new LinksUpdate( $this->title, $parserOutput, false );
 333                 $update->doUpdate();
 334                 wfProfileOut( __METHOD__.'-update' );
 335                 wfProfileOut( __METHOD__ );
 336                 return true;
 337         }
 338 }
 339
 340 class EmaillingJob extends Job {
 341         function __construct($params) {
 342                 parent::__construct('sendMail', Title::newMainPage(), $params);
 343         }
 344
 345         function run() {
 346                 userMailer($this->params['to'], $this->params['from'], $this->params['subj'],
 347                                 $this->params['body'], $this->params['replyto']);
 348         }
 349 }
 350
 351 class EnotifNotifyJob extends Job {
 352         function __construct($title, $params) {
 353                 parent::__construct('enotifNotify', $title, $params);
 354         }
 355
 356         function run() {
 357                 $enotif = new EmailNotification();
 358                 $enotif->actuallyNotifyOnPageChange( User::newFromName($this->params['editor'], false),
 359                                 $this->title, $this->params['timestamp'],
 360                                 $this->params['summary'], $this->params['minorEdit'],
 361                                 $this->params['oldid']);
 362         }
 363 }
 364
 365
 366 ?>