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