includes/libs/rdbms/lbfactory/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 = [];
  32
  33         /** @var array[] Map of (server index => server config) */
  34         private $servers = [];
  35         /** @var array[] Map of (cluster => (server index => server config)) */
  36         private $externalClusters = [];
  37
  38         /** @var string */
  39         private $loadMonitorClass;
  40
  41         public function __construct( array $conf ) {
  42                 parent::__construct( $conf );
  43
  44                 $this->servers = isset( $conf['servers'] ) ? $conf['servers'] : [];
  45                 foreach ( $this->servers as $i => $server ) {
  46                         if ( $i == 0 ) {
  47                                 $this->servers[$i]['master'] = true;
  48                         } else {
  49                                 $this->servers[$i]['replica'] = true;
  50                         }
  51                 }
  52
  53                 $this->externalClusters = isset( $conf['externalClusters'] )
  54                         ? $conf['externalClusters']
  55                         : [];
  56                 $this->loadMonitorClass = isset( $conf['loadMonitorClass'] )
  57                         ? $conf['loadMonitorClass']
  58                         : null;
  59         }
  60
  61         /**
  62          * @param bool|string $domain
  63          * @return LoadBalancer
  64          */
  65         public function newMainLB( $domain = false ) {
  66                 return $this->newLoadBalancer( $this->servers );
  67         }
  68
  69         /**
  70          * @param bool|string $domain
  71          * @return LoadBalancer
  72          */
  73         public function getMainLB( $domain = false ) {
  74                 if ( !isset( $this->mainLB ) ) {
  75                         $this->mainLB = $this->newMainLB( $domain );
  76                         $this->getChronologyProtector()->initLB( $this->mainLB );
  77                 }
  78
  79                 return $this->mainLB;
  80         }
  81
  82         /**
  83          * @param string $cluster
  84          * @param bool|string $domain
  85          * @return LoadBalancer
  86          * @throws InvalidArgumentException
  87          */
  88         protected function newExternalLB( $cluster, $domain = false ) {
  89                 if ( !isset( $this->externalClusters[$cluster] ) ) {
  90                         throw new InvalidArgumentException( __METHOD__ . ": Unknown cluster \"$cluster\"" );
  91                 }
  92
  93                 return $this->newLoadBalancer( $this->externalClusters[$cluster] );
  94         }
  95
  96         /**
  97          * @param string $cluster
  98          * @param bool|string $domain
  99          * @return array
 100          */
 101         public function getExternalLB( $cluster, $domain = false ) {
 102                 if ( !isset( $this->extLBs[$cluster] ) ) {
 103                         $this->extLBs[$cluster] = $this->newExternalLB( $cluster, $domain );
 104                         $this->getChronologyProtector()->initLB( $this->extLBs[$cluster] );
 105                 }
 106
 107                 return $this->extLBs[$cluster];
 108         }
 109
 110         private function newLoadBalancer( array $servers ) {
 111                 $lb = new LoadBalancer( array_merge(
 112                         $this->baseLoadBalancerParams(),
 113                         [
 114                                 'servers' => $servers,
 115                                 'loadMonitor' => $this->loadMonitorClass,
 116                         ]
 117                 ) );
 118                 $this->initLoadBalancer( $lb );
 119
 120                 return $lb;
 121         }
 122
 123         /**
 124          * Execute a function for each tracked load balancer
 125          * The callback is called with the load balancer as the first parameter,
 126          * and $params passed as the subsequent parameters.
 127          *
 128          * @param callable $callback
 129          * @param array $params
 130          */
 131         public function forEachLB( $callback, array $params = [] ) {
 132                 if ( isset( $this->mainLB ) ) {
 133                         call_user_func_array( $callback, array_merge( [ $this->mainLB ], $params ) );
 134                 }
 135                 foreach ( $this->extLBs as $lb ) {
 136                         call_user_func_array( $callback, array_merge( [ $lb ], $params ) );
 137                 }
 138         }
 139 }