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                 ) );
  94         }
  95
  96         /**
  97          * @param bool|string $wiki
  98          * @return LoadBalancer
  99          */
 100         public function getMainLB( $wiki = false ) {
 101                 if ( !isset( $this->mainLB ) ) {
 102                         $this->mainLB = $this->newMainLB( $wiki );
 103                         $this->mainLB->parentInfo( array( 'id' => 'main' ) );
 104                         $this->chronProt->initLB( $this->mainLB );
 105                 }
 106
 107                 return $this->mainLB;
 108         }
 109
 110         /**
 111          * @throws MWException
 112          * @param string $cluster
 113          * @param bool|string $wiki
 114          * @return LoadBalancer
 115          */
 116         protected function newExternalLB( $cluster, $wiki = false ) {
 117                 global $wgExternalServers;
 118                 if ( !isset( $wgExternalServers[$cluster] ) ) {
 119                         throw new MWException( __METHOD__ . ": Unknown cluster \"$cluster\"" );
 120                 }
 121
 122                 return new LoadBalancer( array(
 123                         'servers' => $wgExternalServers[$cluster],
 124                         'loadMonitor' => $this->loadMonitorClass
 125                 ) );
 126         }
 127
 128         /**
 129          * @param string $cluster
 130          * @param bool|string $wiki
 131          * @return array
 132          */
 133         public function &getExternalLB( $cluster, $wiki = false ) {
 134                 if ( !isset( $this->extLBs[$cluster] ) ) {
 135                         $this->extLBs[$cluster] = $this->newExternalLB( $cluster, $wiki );
 136                         $this->extLBs[$cluster]->parentInfo( array( 'id' => "ext-$cluster" ) );
 137                         $this->chronProt->initLB( $this->extLBs[$cluster] );
 138                 }
 139
 140                 return $this->extLBs[$cluster];
 141         }
 142
 143         /**
 144          * Execute a function for each tracked load balancer
 145          * The callback is called with the load balancer as the first parameter,
 146          * and $params passed as the subsequent parameters.
 147          *
 148          * @param callable $callback
 149          * @param array $params
 150          */
 151         public function forEachLB( $callback, array $params = array() ) {
 152                 if ( isset( $this->mainLB ) ) {
 153                         call_user_func_array( $callback, array_merge( array( $this->mainLB ), $params ) );
 154                 }
 155                 foreach ( $this->extLBs as $lb ) {
 156                         call_user_func_array( $callback, array_merge( array( $lb ), $params ) );
 157                 }
 158         }
 159
 160         public function shutdown() {
 161                 if ( $this->mainLB ) {
 162                         $this->chronProt->shutdownLB( $this->mainLB );
 163                 }
 164                 foreach ( $this->extLBs as $extLB ) {
 165                         $this->chronProt->shutdownLB( $extLB );
 166                 }
 167                 $this->chronProt->shutdown();
 168                 $this->commitMasterChanges();
 169         }
 170 }