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 namespace Wikimedia\Rdbms;
  25
  26 use LoadBalancer;
  27 use InvalidArgumentException;
  28
  29 /**
  30  * A simple single-master LBFactory that gets its configuration from the b/c globals
  31  */
  32 class LBFactorySimple extends LBFactory {
  33         /** @var LoadBalancer */
  34         private $mainLB;
  35         /** @var LoadBalancer[] */
  36         private $extLBs = [];
  37
  38         /** @var array[] Map of (server index => server config) */
  39         private $servers = [];
  40         /** @var array[] Map of (cluster => (server index => server config)) */
  41         private $externalClusters = [];
  42
  43         /** @var string */
  44         private $loadMonitorClass;
  45
  46         /**
  47          * @see LBFactory::__construct()
  48          * @param array $conf Parameters of LBFactory::__construct() as well as:
  49          *   - servers : list of server configuration maps to Database::factory().
  50          *      Additionally, the server maps should have a 'load' key, which is used to decide
  51          *      how often clients connect to one server verses the others. A 'max lag' key should
  52          *      also be set on server maps, indicating how stale the data can be before the load
  53          *      balancer tries to avoid using it. The map can have 'is static' set to disable blocking
  54          *      replication sync checks (intended for archive servers with unchanging data).
  55          *   - externalClusters : map of cluster names to server arrays. The servers arrays have the
  56          *      same format as "servers" above.
  57          */
  58         public function __construct( array $conf ) {
  59                 parent::__construct( $conf );
  60
  61                 $this->servers = isset( $conf['servers'] ) ? $conf['servers'] : [];
  62                 foreach ( $this->servers as $i => $server ) {
  63                         if ( $i == 0 ) {
  64                                 $this->servers[$i]['master'] = true;
  65                         } else {
  66                                 $this->servers[$i]['replica'] = true;
  67                         }
  68                 }
  69
  70                 $this->externalClusters = isset( $conf['externalClusters'] )
  71                         ? $conf['externalClusters']
  72                         : [];
  73                 $this->loadMonitorClass = isset( $conf['loadMonitorClass'] )
  74                         ? $conf['loadMonitorClass']
  75                         : 'LoadMonitor';
  76         }
  77
  78         /**
  79          * @param bool|string $domain
  80          * @return LoadBalancer
  81          */
  82         public function newMainLB( $domain = false ) {
  83                 return $this->newLoadBalancer( $this->servers );
  84         }
  85
  86         /**
  87          * @param bool|string $domain
  88          * @return LoadBalancer
  89          */
  90         public function getMainLB( $domain = false ) {
  91                 if ( !isset( $this->mainLB ) ) {
  92                         $this->mainLB = $this->newMainLB( $domain );
  93                         $this->getChronologyProtector()->initLB( $this->mainLB );
  94                 }
  95
  96                 return $this->mainLB;
  97         }
  98
  99         public function newExternalLB( $cluster ) {
 100                 if ( !isset( $this->externalClusters[$cluster] ) ) {
 101                         throw new InvalidArgumentException( __METHOD__ . ": Unknown cluster \"$cluster\"." );
 102                 }
 103
 104                 return $this->newLoadBalancer( $this->externalClusters[$cluster] );
 105         }
 106
 107         public function getExternalLB( $cluster ) {
 108                 if ( !isset( $this->extLBs[$cluster] ) ) {
 109                         $this->extLBs[$cluster] = $this->newExternalLB( $cluster );
 110                         $this->getChronologyProtector()->initLB( $this->extLBs[$cluster] );
 111                 }
 112
 113                 return $this->extLBs[$cluster];
 114         }
 115
 116         public function getAllMainLBs() {
 117                 return [ 'DEFAULT' => $this->getMainLB() ];
 118         }
 119
 120         public function getAllExternalLBs() {
 121                 $lbs = [];
 122                 foreach ( $this->externalClusters as $cluster => $unused ) {
 123                         $lbs[$cluster] = $this->getExternalLB( $cluster );
 124                 }
 125
 126                 return $lbs;
 127         }
 128
 129         private function newLoadBalancer( array $servers ) {
 130                 $lb = new LoadBalancer( array_merge(
 131                         $this->baseLoadBalancerParams(),
 132                         [
 133                                 'servers' => $servers,
 134                                 'loadMonitor' => [ 'class' => $this->loadMonitorClass ],
 135                         ]
 136                 ) );
 137                 $this->initLoadBalancer( $lb );
 138
 139                 return $lb;
 140         }
 141
 142         /**
 143          * Execute a function for each tracked load balancer
 144          * The callback is called with the load balancer as the first parameter,
 145          * and $params passed as the subsequent parameters.
 146          *
 147          * @param callable $callback
 148          * @param array $params
 149          */
 150         public function forEachLB( $callback, array $params = [] ) {
 151                 if ( isset( $this->mainLB ) ) {
 152                         call_user_func_array( $callback, array_merge( [ $this->mainLB ], $params ) );
 153                 }
 154                 foreach ( $this->extLBs as $lb ) {
 155                         call_user_func_array( $callback, array_merge( [ $lb ], $params ) );
 156                 }
 157         }
 158 }