1<?php 2/** 3 * Simple generator of database connections that always returns the same object. 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 24namespace Wikimedia\Rdbms; 25 26use InvalidArgumentException; 27 28/** 29 * Trivial LoadBalancer that always returns an injected connection handle. 30 */ 31class LoadBalancerSingle extends LoadBalancer { 32 /** @var IDatabase */ 33 private $db; 34 35 /** 36 * You probably want to use {@link newFromConnection} instead. 37 * 38 * @param array $params An associative array with one member: 39 * - connection: An IDatabase connection object 40 */ 41 public function __construct( array $params ) { 42 /** @var IDatabase $conn */ 43 $conn = $params['connection'] ?? null; 44 if ( !$conn ) { 45 throw new InvalidArgumentException( "Missing 'connection' argument." ); 46 } 47 48 $this->db = $conn; 49 50 parent::__construct( [ 51 'servers' => [ [ 52 'type' => $conn->getType(), 53 'host' => $conn->getServer(), 54 'dbname' => $conn->getDBname(), 55 'load' => 1, 56 ] ], 57 'trxProfiler' => $params['trxProfiler'] ?? null, 58 'srvCache' => $params['srvCache'] ?? null, 59 'wanCache' => $params['wanCache'] ?? null, 60 'localDomain' => $params['localDomain'] ?? $this->db->getDomainID(), 61 'readOnlyReason' => $params['readOnlyReason'] ?? false, 62 'clusterName' => $params['clusterName'] ?? null, 63 ] ); 64 65 if ( isset( $params['readOnlyReason'] ) ) { 66 $conn->setLBInfo( $conn::LB_READ_ONLY_REASON, $params['readOnlyReason'] ); 67 } 68 } 69 70 /** 71 * @param IDatabase $db Live connection handle 72 * @param array $params Parameter map to LoadBalancerSingle::__constructs() 73 * @return LoadBalancerSingle 74 * @since 1.28 75 */ 76 public static function newFromConnection( IDatabase $db, array $params = [] ) { 77 return new static( array_merge( 78 [ 'localDomain' => $db->getDomainID() ], 79 $params, 80 [ 'connection' => $db ] 81 ) ); 82 } 83 84 protected function reallyOpenConnection( $i, DatabaseDomain $domain, array $lbInfo = [] ) { 85 return $this->db; 86 } 87 88 public function __destruct() { 89 // do nothing since the connection was injected 90 } 91} 92 93/** 94 * @deprecated since 1.29 95 */ 96class_alias( LoadBalancerSingle::class, 'LoadBalancerSingle' ); 97