includes/libs/rdbms/lbfactory/LBFactorySingle.php

   1 <?php
   2 /**
   3  * This program is free software; you can redistribute it and/or modify
   4  * it under the terms of the GNU General Public License as published by
   5  * the Free Software Foundation; either version 2 of the License, or
   6  * (at your option) any later version.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  11  * GNU General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public License along
  14  * with this program; if not, write to the Free Software Foundation, Inc.,
  15  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  16  * http://www.gnu.org/copyleft/gpl.html
  17  *
  18  * @file
  19  */
  20 namespace Wikimedia\Rdbms;
  21
  22 use BadMethodCallException;
  23 use InvalidArgumentException;
  24
  25 /**
  26  * LoadBalancer manager for sites with one "main" cluster using only injected database connections
  27  *
  28  * This class assumes that there are no "external" clusters.
  29  *
  30  * LoadBalancerDisabled will be used if a null connection handle is injected.
  31  *
  32  * @see ILBFactory
  33  * @ingroup Database
  34  */
  35 class LBFactorySingle extends LBFactory {
  36         /** @var LoadBalancerSingle|LoadBalancerDisabled */
  37         private $mainLB;
  38
  39         /**
  40          * @note Use of {@link newFromConnection} is preferable
  41          *
  42          * @param array $conf An associative array containing one of the following:
  43          *  - connection: The IDatabase connection handle to use; null to disable access
  44          */
  45         public function __construct( array $conf ) {
  46                 parent::__construct( $conf );
  47
  48                 if ( !array_key_exists( 'connection', $conf ) ) {
  49                         throw new InvalidArgumentException( "Missing 'connection' argument." );
  50                 }
  51
  52                 $conn = $conf['connection'];
  53                 if ( $conn ) {
  54                         $mainLB = new LoadBalancerSingle( array_merge(
  55                                 $this->baseLoadBalancerParams(),
  56                                 [ 'connection' => $conn ]
  57                         ) );
  58                 } else {
  59                         $mainLB = new LoadBalancerDisabled( $this->baseLoadBalancerParams() );
  60                 }
  61                 $this->initLoadBalancer( $mainLB );
  62
  63                 $this->mainLB = $mainLB;
  64         }
  65
  66         /**
  67          * @param IDatabase $db Live connection handle
  68          * @param array $params Parameter map to LBFactorySingle::__construct()
  69          * @return LBFactorySingle
  70          * @since 1.28
  71          */
  72         public static function newFromConnection( IDatabase $db, array $params = [] ) {
  73                 return new static( array_merge(
  74                         [ 'localDomain' => $db->getDomainID() ],
  75                         $params,
  76                         [ 'connection' => $db ]
  77                 ) );
  78         }
  79
  80         /**
  81          * @param array $params Parameter map to LBFactorySingle::__construct()
  82          * @return LBFactorySingle
  83          * @since 1.40
  84          */
  85         public static function newDisabled( array $params = [] ) {
  86                 return new static( array_merge(
  87                         $params,
  88                         [ 'connection' => null ]
  89                 ) );
  90         }
  91
  92         public function newMainLB( $domain = false ): ILoadBalancerForOwner {
  93                 // @phan-suppress-previous-line PhanPluginNeverReturnMethod
  94                 throw new BadMethodCallException( "Method is not supported." );
  95         }
  96
  97         public function getMainLB( $domain = false ): ILoadBalancer {
  98                 return $this->mainLB;
  99         }
 100
 101         public function newExternalLB( $cluster ): ILoadBalancerForOwner {
 102                 // @phan-suppress-previous-line PhanPluginNeverReturnMethod
 103                 throw new BadMethodCallException( "Method is not supported." );
 104         }
 105
 106         public function getExternalLB( $cluster ): ILoadBalancer {
 107                 // @phan-suppress-previous-line PhanPluginNeverReturnMethod
 108                 throw new BadMethodCallException( "Method is not supported." );
 109         }
 110
 111         public function getAllMainLBs(): array {
 112                 return [ self::CLUSTER_MAIN_DEFAULT => $this->mainLB ];
 113         }
 114
 115         public function getAllExternalLBs(): array {
 116                 return [];
 117         }
 118
 119         protected function getLBsForOwner() {
 120                 if ( $this->mainLB !== null ) {
 121                         yield $this->mainLB;
 122                 }
 123         }
 124
 125         public function __destruct() {
 126                 // do nothing since the connection was injected
 127         }
 128 }