includes/libs/rdbms/connectionmanager/ConnectionManager.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  * @ingroup Database
  20  */
  21
  22 namespace Wikimedia\Rdbms;
  23
  24 use InvalidArgumentException;
  25
  26 /**
  27  * Database connection manager.
  28  *
  29  * This manages access to master and replica databases.
  30  *
  31  * @since 1.29
  32  *
  33  * @author Addshore
  34  */
  35 class ConnectionManager {
  36
  37         /**
  38          * @var LoadBalancer
  39          */
  40         private $loadBalancer;
  41
  42         /**
  43          * The symbolic name of the target database, or false for the local wiki's database.
  44          *
  45          * @var string|false
  46          */
  47         private $domain;
  48
  49         /**
  50          * @var string[]
  51          */
  52         private $groups = [];
  53
  54         /**
  55          * @param LoadBalancer $loadBalancer
  56          * @param string|bool $domain Optional logical DB name, defaults to current wiki.
  57          *        This follows the convention for database names used by $loadBalancer.
  58          * @param string[] $groups see LoadBalancer::getConnection
  59          *
  60          * @throws InvalidArgumentException
  61          */
  62         public function __construct( LoadBalancer $loadBalancer, $domain = false, array $groups = [] ) {
  63                 if ( !is_string( $domain ) && $domain !== false ) {
  64                         throw new InvalidArgumentException( '$dbName must be a string, or false.' );
  65                 }
  66
  67                 $this->loadBalancer = $loadBalancer;
  68                 $this->domain = $domain;
  69                 $this->groups = $groups;
  70         }
  71
  72         /**
  73          * @param int $i
  74          * @param string[]|null $groups
  75          *
  76          * @return Database
  77          */
  78         private function getConnection( $i, array $groups = null ) {
  79                 $groups = $groups === null ? $this->groups : $groups;
  80                 return $this->loadBalancer->getConnection( $i, $groups, $this->domain );
  81         }
  82
  83         /**
  84          * @param int $i
  85          * @param string[]|null $groups
  86          *
  87          * @return DBConnRef
  88          */
  89         private function getConnectionRef( $i, array $groups = null ) {
  90                 $groups = $groups === null ? $this->groups : $groups;
  91                 return $this->loadBalancer->getConnectionRef( $i, $groups, $this->domain );
  92         }
  93
  94         /**
  95          * Returns a connection to the master DB, for updating. The connection should later be released
  96          * by calling releaseConnection().
  97          *
  98          * @since 1.29
  99          *
 100          * @return Database
 101          */
 102         public function getWriteConnection() {
 103                 return $this->getConnection( DB_MASTER );
 104         }
 105
 106         /**
 107          * Returns a database connection for reading. The connection should later be released by
 108          * calling releaseConnection().
 109          *
 110          * @since 1.29
 111          *
 112          * @param string[]|null $groups
 113          *
 114          * @return Database
 115          */
 116         public function getReadConnection( array $groups = null ) {
 117                 $groups = $groups === null ? $this->groups : $groups;
 118                 return $this->getConnection( DB_REPLICA, $groups );
 119         }
 120
 121         /**
 122          * @since 1.29
 123          *
 124          * @param IDatabase $db
 125          */
 126         public function releaseConnection( IDatabase $db ) {
 127                 $this->loadBalancer->reuseConnection( $db );
 128         }
 129
 130         /**
 131          * Returns a connection ref to the master DB, for updating.
 132          *
 133          * @since 1.29
 134          *
 135          * @return DBConnRef
 136          */
 137         public function getWriteConnectionRef() {
 138                 return $this->getConnectionRef( DB_MASTER );
 139         }
 140
 141         /**
 142          * Returns a database connection ref for reading.
 143          *
 144          * @since 1.29
 145          *
 146          * @param string[]|null $groups
 147          *
 148          * @return DBConnRef
 149          */
 150         public function getReadConnectionRef( array $groups = null ) {
 151                 $groups = $groups === null ? $this->groups : $groups;
 152                 return $this->getConnectionRef( DB_REPLICA, $groups );
 153         }
 154
 155 }