maintenance/nextJobDB.php

   1 <?php
   2 /**
   3  * Pick a database that has pending jobs
   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  * @ingroup Maintenance
  22  */
  23
  24 require_once( __DIR__ . '/Maintenance.php' );
  25
  26 /**
  27  * Maintenance script that picks a database that has pending jobs.
  28  *
  29  * @ingroup Maintenance
  30  */
  31 class nextJobDB extends Maintenance {
  32         public function __construct() {
  33                 parent::__construct();
  34                 $this->mDescription = "Pick a database that has pending jobs";
  35                 $this->addOption( 'type', "Search by job type", false, true );
  36                 $this->addOption( 'types', "Space separated list of job types to search for", false, true );
  37         }
  38
  39         public function execute() {
  40                 global $wgMemc, $wgJobTypesExcludedFromDefaultQueue;
  41
  42                 $type = false; // job type required/picked
  43
  44                 if ( $this->hasOption( 'types' ) ) {
  45                         $types = explode( ' ', $this->getOption( 'types' ) );
  46                 } elseif ( $this->hasOption( 'type' ) ) {
  47                         $types = array( $this->getOption( 'type' ) );
  48                 } else {
  49                         $types = false;
  50                 }
  51
  52                 // Handle any required periodic queue maintenance
  53                 $this->executeReadyPeriodicTasks();
  54
  55                 // Get all the queues with jobs in them
  56                 $pendingDBs = JobQueueAggregator::singleton()->getAllReadyWikiQueues();
  57                 if ( !count( $pendingDBs ) ) {
  58                         return; // no DBs with jobs or cache is both empty and locked
  59                 }
  60
  61                 do {
  62                         $again = false;
  63
  64                         $candidates = array(); // list of (type, db)
  65                         // Flatten the tree of candidates into a flat list so that a random
  66                         // item can be selected, weighing each queue (type/db tuple) equally.
  67                         foreach ( $pendingDBs as $type => $dbs ) {
  68                                 if (
  69                                         ( is_array( $types ) && in_array( $type, $types ) ) ||
  70                                         ( $types === false && !in_array( $type, $wgJobTypesExcludedFromDefaultQueue ) )
  71                                 ) {
  72                                         foreach ( $dbs as $db ) {
  73                                                 $candidates[] = array( $type, $db );
  74                                         }
  75                                 }
  76                         }
  77                         if ( !count( $candidates ) ) {
  78                                 return; // no jobs for this type
  79                         }
  80
  81                         list( $type, $db ) = $candidates[ mt_rand( 0, count( $candidates ) - 1 ) ];
  82                         if ( !$this->checkJob( $type, $db ) ) { // queue is actually empty?
  83                                 $pendingDBs[$type] = array_diff( $pendingDBs[$type], $db );
  84                                 JobQueueAggregator::singleton()->notifyQueueEmpty( $db, $type );
  85                                 $again = true;
  86                         }
  87                 } while ( $again );
  88
  89                 if ( $this->hasOption( 'types' ) ) {
  90                         $this->output( $db . " " . $type . "\n" );
  91                 } else {
  92                         $this->output( $db . "\n" );
  93                 }
  94         }
  95
  96         /**
  97          * Check if the specified database has a job of the specified type in it.
  98          * The type may be false to indicate "all".
  99          * @param $type string
 100          * @param $dbName string
 101          * @return bool
 102          */
 103         private function checkJob( $type, $dbName ) {
 104                 return !JobQueueGroup::singleton( $dbName )->get( $type )->isEmpty();
 105         }
 106
 107         /**
 108          * Do all ready periodic jobs for all databases every 5 minutes (and .1% of the time)
 109          * @return integer
 110          */
 111         private function executeReadyPeriodicTasks() {
 112                 global $wgLocalDatabases, $wgMemc;
 113
 114                 $count = 0;
 115                 $memcKey = 'jobqueue:periodic:lasttime';
 116                 $timestamp = (int)$wgMemc->get( $memcKey ); // UNIX timestamp or 0
 117                 if ( ( time() - $timestamp ) > 300 || mt_rand( 0, 999 ) == 0 ) { // 5 minutes
 118                         if ( $wgMemc->add( "$memcKey:rebuild", 1, 1800 ) ) { // lock
 119                                 foreach ( $wgLocalDatabases as $db ) {
 120                                         $count += JobQueueGroup::singleton( $db )->executeReadyPeriodicTasks();
 121                                 }
 122                                 $wgMemc->set( $memcKey, time() );
 123                                 $wgMemc->delete( "$memcKey:rebuild" ); // unlock
 124                         }
 125                 }
 126
 127                 return $count;
 128         }
 129 }
 130
 131 $maintClass = "nextJobDb";
 132 require_once( RUN_MAINTENANCE_IF_MAIN );