includes/libs/objectcache/ReplicatedBagOStuff.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 Cache
  20  * @author Aaron Schulz
  21  */
  22
  23 /**
  24  * A cache class that directs writes to one set of servers and reads to
  25  * another. This assumes that the servers used for reads are setup to replica DB
  26  * those that writes go to. This can easily be used with redis for example.
  27  *
  28  * In the WAN scenario (e.g. multi-datacenter case), this is useful when
  29  * writes are rare or they usually take place in the primary datacenter.
  30  *
  31  * @ingroup Cache
  32  * @since 1.26
  33  */
  34 class ReplicatedBagOStuff extends BagOStuff {
  35         /** @var BagOStuff */
  36         protected $writeStore;
  37         /** @var BagOStuff */
  38         protected $readStore;
  39
  40         /**
  41          * Constructor. Parameters are:
  42          *   - writeFactory : ObjectFactory::getObjectFromSpec array yeilding BagOStuff.
  43          *                    This object will be used for writes (e.g. the master DB).
  44          *   - readFactory  : ObjectFactory::getObjectFromSpec array yeilding BagOStuff.
  45          *                    This object will be used for reads (e.g. a replica DB).
  46          *
  47          * @param array $params
  48          * @throws InvalidArgumentException
  49          */
  50         public function __construct( $params ) {
  51                 parent::__construct( $params );
  52
  53                 if ( !isset( $params['writeFactory'] ) ) {
  54                         throw new InvalidArgumentException(
  55                                 __METHOD__ . ': the "writeFactory" parameter is required' );
  56                 }
  57                 if ( !isset( $params['readFactory'] ) ) {
  58                         throw new InvalidArgumentException(
  59                                 __METHOD__ . ': the "readFactory" parameter is required' );
  60                 }
  61
  62                 $opts = [ 'reportDupes' => false ]; // redundant
  63                 $this->writeStore = ( $params['writeFactory'] instanceof BagOStuff )
  64                         ? $params['writeFactory']
  65                         : ObjectFactory::getObjectFromSpec( $opts + $params['writeFactory'] );
  66                 $this->readStore = ( $params['readFactory'] instanceof BagOStuff )
  67                         ? $params['readFactory']
  68                         : ObjectFactory::getObjectFromSpec( $opts + $params['readFactory'] );
  69                 $this->attrMap = $this->mergeFlagMaps( [ $this->readStore, $this->writeStore ] );
  70         }
  71
  72         public function setDebug( $debug ) {
  73                 $this->writeStore->setDebug( $debug );
  74                 $this->readStore->setDebug( $debug );
  75         }
  76
  77         protected function doGet( $key, $flags = 0 ) {
  78                 return ( $flags & self::READ_LATEST )
  79                         ? $this->writeStore->get( $key, $flags )
  80                         : $this->readStore->get( $key, $flags );
  81         }
  82
  83         public function getMulti( array $keys, $flags = 0 ) {
  84                 return ( $flags & self::READ_LATEST )
  85                         ? $this->writeStore->getMulti( $keys, $flags )
  86                         : $this->readStore->getMulti( $keys, $flags );
  87         }
  88
  89         public function set( $key, $value, $exptime = 0, $flags = 0 ) {
  90                 return $this->writeStore->set( $key, $value, $exptime, $flags );
  91         }
  92
  93         public function delete( $key ) {
  94                 return $this->writeStore->delete( $key );
  95         }
  96
  97         public function add( $key, $value, $exptime = 0 ) {
  98                 return $this->writeStore->add( $key, $value, $exptime );
  99         }
 100
 101         public function incr( $key, $value = 1 ) {
 102                 return $this->writeStore->incr( $key, $value );
 103         }
 104
 105         public function decr( $key, $value = 1 ) {
 106                 return $this->writeStore->decr( $key, $value );
 107         }
 108
 109         public function lock( $key, $timeout = 6, $expiry = 6, $rclass = '' ) {
 110                 return $this->writeStore->lock( $key, $timeout, $expiry, $rclass );
 111         }
 112
 113         public function unlock( $key ) {
 114                 return $this->writeStore->unlock( $key );
 115         }
 116
 117         public function merge( $key, callable $callback, $exptime = 0, $attempts = 10, $flags = 0 ) {
 118                 return $this->writeStore->merge( $key, $callback, $exptime, $attempts, $flags );
 119         }
 120
 121         public function getLastError() {
 122                 return ( $this->writeStore->getLastError() != self::ERR_NONE )
 123                         ? $this->writeStore->getLastError()
 124                         : $this->readStore->getLastError();
 125         }
 126
 127         public function clearLastError() {
 128                 $this->writeStore->clearLastError();
 129                 $this->readStore->clearLastError();
 130         }
 131 }