includes/db/loadbalancer/LBFactorySimple.php

   1 <?php
   2 /**
   3  * Generator of database load balancing objects.
   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 Database
  22  */
  23
  24 /**
  25  * A simple single-master LBFactory that gets its configuration from the b/c globals
  26  */
  27 class LBFactorySimple extends LBFactory {
  28         /** @var LoadBalancer */
  29         private $mainLB;
  30         /** @var LoadBalancer[] */
  31         private $extLBs = array();
  32         /** @var ChronologyProtector */
  33         private $chronProt;
  34
  35         /** @var string */
  36         private $loadMonitorClass;
  37
  38         public function __construct( array $conf ) {
  39                 parent::__construct( $conf );
  40
  41                 $this->chronProt = new ChronologyProtector;
  42                 $this->loadMonitorClass = isset( $conf['loadMonitorClass'] )
  43                         ? $conf['loadMonitorClass']
  44                         : null;
  45         }
  46
  47         /**
  48          * @param bool|string $wiki
  49          * @return LoadBalancer
  50          */
  51         public function newMainLB( $wiki = false ) {
  52                 global $wgDBservers;
  53
  54                 if ( is_array( $wgDBservers ) ) {
  55                         $servers = $wgDBservers;
  56                         foreach ( $servers as $i => &$server ) {
  57                                 if ( $i == 0 ) {
  58                                         $server['master'] = true;
  59                                 } else {
  60                                         $server['slave'] = true;
  61                                 }
  62                         }
  63                 } else {
  64                         global $wgDBserver, $wgDBuser, $wgDBpassword, $wgDBname, $wgDBtype, $wgDebugDumpSql;
  65                         global $wgDBssl, $wgDBcompress;
  66
  67                         $flags = DBO_DEFAULT;
  68                         if ( $wgDebugDumpSql ) {
  69                                 $flags |= DBO_DEBUG;
  70                         }
  71                         if ( $wgDBssl ) {
  72                                 $flags |= DBO_SSL;
  73                         }
  74                         if ( $wgDBcompress ) {
  75                                 $flags |= DBO_COMPRESS;
  76                         }
  77
  78                         $servers = array( array(
  79                                 'host' => $wgDBserver,
  80                                 'user' => $wgDBuser,
  81                                 'password' => $wgDBpassword,
  82                                 'dbname' => $wgDBname,
  83                                 'type' => $wgDBtype,
  84                                 'load' => 1,
  85                                 'flags' => $flags,
  86                                 'master' => true
  87                         ) );
  88                 }
  89
  90                 return new LoadBalancer( array(
  91                         'servers' => $servers,
  92                         'loadMonitor' => $this->loadMonitorClass,
  93                         'readOnlyReason' => $this->readOnlyReason
  94                 ) );
  95         }
  96
  97         /**
  98          * @param bool|string $wiki
  99          * @return LoadBalancer
 100          */
 101         public function getMainLB( $wiki = false ) {
 102                 if ( !isset( $this->mainLB ) ) {
 103                         $this->mainLB = $this->newMainLB( $wiki );
 104                         $this->mainLB->parentInfo( array( 'id' => 'main' ) );
 105                         $this->chronProt->initLB( $this->mainLB );
 106                 }
 107
 108                 return $this->mainLB;
 109         }
 110
 111         /**
 112          * @throws MWException
 113          * @param string $cluster
 114          * @param bool|string $wiki
 115          * @return LoadBalancer
 116          */
 117         protected function newExternalLB( $cluster, $wiki = false ) {
 118                 global $wgExternalServers;
 119                 if ( !isset( $wgExternalServers[$cluster] ) ) {
 120                         throw new MWException( __METHOD__ . ": Unknown cluster \"$cluster\"" );
 121                 }
 122
 123                 return new LoadBalancer( array(
 124                         'servers' => $wgExternalServers[$cluster],
 125                         'loadMonitor' => $this->loadMonitorClass,
 126                         'readOnlyReason' => $this->readOnlyReason
 127                 ) );
 128         }
 129
 130         /**
 131          * @param string $cluster
 132          * @param bool|string $wiki
 133          * @return array
 134          */
 135         public function &getExternalLB( $cluster, $wiki = false ) {
 136                 if ( !isset( $this->extLBs[$cluster] ) ) {
 137                         $this->extLBs[$cluster] = $this->newExternalLB( $cluster, $wiki );
 138                         $this->extLBs[$cluster]->parentInfo( array( 'id' => "ext-$cluster" ) );
 139                         $this->chronProt->initLB( $this->extLBs[$cluster] );
 140                 }
 141
 142                 return $this->extLBs[$cluster];
 143         }
 144
 145         /**
 146          * Execute a function for each tracked load balancer
 147          * The callback is called with the load balancer as the first parameter,
 148          * and $params passed as the subsequent parameters.
 149          *
 150          * @param callable $callback
 151          * @param array $params
 152          */
 153         public function forEachLB( $callback, array $params = array() ) {
 154                 if ( isset( $this->mainLB ) ) {
 155                         call_user_func_array( $callback, array_merge( array( $this->mainLB ), $params ) );
 156                 }
 157                 foreach ( $this->extLBs as $lb ) {
 158                         call_user_func_array( $callback, array_merge( array( $lb ), $params ) );
 159                 }
 160         }
 161
 162         public function shutdown() {
 163                 if ( $this->mainLB ) {
 164                         $this->chronProt->shutdownLB( $this->mainLB );
 165                 }
 166                 foreach ( $this->extLBs as $extLB ) {
 167                         $this->chronProt->shutdownLB( $extLB );
 168                 }
 169                 $this->chronProt->shutdown();
 170                 $this->commitMasterChanges();
 171         }
 172 }