includes/libs/rdbms/connectionmanager/ConnectionManager.php

   1 <?php
   2
   3 namespace Wikimedia\Rdbms;
   4
   5 use Database;
   6 use InvalidArgumentException;
   7
   8 /**
   9  * Database connection manager.
  10  *
  11  * This manages access to master and replica databases.
  12  *
  13  * @since 1.29
  14  *
  15  * @license GPL-2.0+
  16  * @author Addshore
  17  */
  18 class ConnectionManager {
  19
  20         /**
  21          * @var LoadBalancer
  22          */
  23         private $loadBalancer;
  24
  25         /**
  26          * The symbolic name of the target database, or false for the local wiki's database.
  27          *
  28          * @var string|false
  29          */
  30         private $domain;
  31
  32         /**
  33          * @var string[]
  34          */
  35         private $groups = [];
  36
  37         /**
  38          * @param LoadBalancer $loadBalancer
  39          * @param string|bool $domain Optional logical DB name, defaults to current wiki.
  40          *        This follows the convention for database names used by $loadBalancer.
  41          * @param string[] $groups see LoadBalancer::getConnection
  42          *
  43          * @throws InvalidArgumentException
  44          */
  45         public function __construct( LoadBalancer $loadBalancer, $domain = false, array $groups = [] ) {
  46                 if ( !is_string( $domain ) && $domain !== false ) {
  47                         throw new InvalidArgumentException( '$dbName must be a string, or false.' );
  48                 }
  49
  50                 $this->loadBalancer = $loadBalancer;
  51                 $this->domain = $domain;
  52                 $this->groups = $groups;
  53         }
  54
  55         /**
  56          * @param int $i
  57          * @param string[]|null $groups
  58          *
  59          * @return Database
  60          */
  61         private function getConnection( $i, array $groups = null ) {
  62                 $groups = $groups === null ? $this->groups : $groups;
  63                 return $this->loadBalancer->getConnection( $i, $groups, $this->domain );
  64         }
  65
  66         /**
  67          * @param int $i
  68          * @param string[]|null $groups
  69          *
  70          * @return DBConnRef
  71          */
  72         private function getConnectionRef( $i, array $groups = null ) {
  73                 $groups = $groups === null ? $this->groups : $groups;
  74                 return $this->loadBalancer->getConnectionRef( $i, $groups, $this->domain );
  75         }
  76
  77         /**
  78          * Returns a connection to the master DB, for updating. The connection should later be released
  79          * by calling releaseConnection().
  80          *
  81          * @since 1.29
  82          *
  83          * @return Database
  84          */
  85         public function getWriteConnection() {
  86                 return $this->getConnection( DB_MASTER );
  87         }
  88
  89         /**
  90          * Returns a database connection for reading. The connection should later be released by
  91          * calling releaseConnection().
  92          *
  93          * @since 1.29
  94          *
  95          * @param string[]|null $groups
  96          *
  97          * @return Database
  98          */
  99         public function getReadConnection( array $groups = null ) {
 100                 $groups = $groups === null ? $this->groups : $groups;
 101                 return $this->getConnection( DB_REPLICA, $groups );
 102         }
 103
 104         /**
 105          * @since 1.29
 106          *
 107          * @param IDatabase $db
 108          */
 109         public function releaseConnection( IDatabase $db ) {
 110                 $this->loadBalancer->reuseConnection( $db );
 111         }
 112
 113         /**
 114          * Returns a connection ref to the master DB, for updating.
 115          *
 116          * @since 1.29
 117          *
 118          * @return DBConnRef
 119          */
 120         public function getWriteConnectionRef() {
 121                 return $this->getConnectionRef( DB_MASTER );
 122         }
 123
 124         /**
 125          * Returns a database connection ref for reading.
 126          *
 127          * @since 1.29
 128          *
 129          * @param string[]|null $groups
 130          *
 131          * @return DBConnRef
 132          */
 133         public function getReadConnectionRef( array $groups = null ) {
 134                 $groups = $groups === null ? $this->groups : $groups;
 135                 return $this->getConnectionRef( DB_REPLICA, $groups );
 136         }
 137
 138 }