includes/objectcache/MemcachedPeclBagOStuff.php

   1 <?php
   2 /**
   3  * Object caching using memcached.
   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 Cache
  22  */
  23
  24 /**
  25  * A wrapper class for the PECL memcached client
  26  *
  27  * @ingroup Cache
  28  */
  29 class MemcachedPeclBagOStuff extends MemcachedBagOStuff {
  30
  31         /**
  32          * Constructor
  33          *
  34          * Available parameters are:
  35          *   - servers:             The list of IP:port combinations holding the memcached servers.
  36          *   - persistent:          Whether to use a persistent connection
  37          *   - compress_threshold:  The minimum size an object must be before it is compressed
  38          *   - timeout:             The read timeout in microseconds
  39          *   - connect_timeout:     The connect timeout in seconds
  40          *   - serializer:          May be either "php" or "igbinary". Igbinary produces more compact
  41          *                          values, but serialization is much slower unless the php.ini option
  42          *                          igbinary.compact_strings is off.
  43          */
  44         function __construct( $params ) {
  45                 $params = $this->applyDefaultParams( $params );
  46
  47                 if ( $params['persistent'] ) {
  48                         // The pool ID must be unique to the server/option combination.
  49                         // The Memcached object is essentially shared for each pool ID.
  50                         // We can only resuse a pool ID if we keep the config consistent.
  51                         $this->client = new Memcached( md5( serialize( $params ) ) );
  52                         if ( count( $this->client->getServerList() ) ) {
  53                                 wfDebug( __METHOD__ . ": persistent Memcached object already loaded.\n" );
  54                                 return; // already initialized; don't add duplicate servers
  55                         }
  56                 } else {
  57                         $this->client = new Memcached;
  58                 }
  59
  60                 if ( !isset( $params['serializer'] ) ) {
  61                         $params['serializer'] = 'php';
  62                 }
  63
  64                 // The compression threshold is an undocumented php.ini option for some
  65                 // reason. There's probably not much harm in setting it globally, for
  66                 // compatibility with the settings for the PHP client.
  67                 ini_set( 'memcached.compression_threshold', $params['compress_threshold'] );
  68
  69                 // Set timeouts
  70                 $this->client->setOption( Memcached::OPT_CONNECT_TIMEOUT, $params['connect_timeout'] * 1000 );
  71                 $this->client->setOption( Memcached::OPT_SEND_TIMEOUT, $params['timeout'] );
  72                 $this->client->setOption( Memcached::OPT_RECV_TIMEOUT, $params['timeout'] );
  73                 $this->client->setOption( Memcached::OPT_POLL_TIMEOUT, $params['timeout'] / 1000 );
  74
  75                 // Set libketama mode since it's recommended by the documentation and
  76                 // is as good as any. There's no way to configure libmemcached to use
  77                 // hashes identical to the ones currently in use by the PHP client, and
  78                 // even implementing one of the libmemcached hashes in pure PHP for
  79                 // forwards compatibility would require MWMemcached::get_sock() to be
  80                 // rewritten.
  81                 $this->client->setOption( Memcached::OPT_LIBKETAMA_COMPATIBLE, true );
  82
  83                 // Set the serializer
  84                 switch ( $params['serializer'] ) {
  85                         case 'php':
  86                                 $this->client->setOption( Memcached::OPT_SERIALIZER, Memcached::SERIALIZER_PHP );
  87                                 break;
  88                         case 'igbinary':
  89                                 if ( !Memcached::HAVE_IGBINARY ) {
  90                                         throw new MWException( __CLASS__.': the igbinary extension is not available ' .
  91                                                 'but igbinary serialization was requested.' );
  92                                 }
  93                                 $this->client->setOption( Memcached::OPT_SERIALIZER, Memcached::SERIALIZER_IGBINARY );
  94                                 break;
  95                         default:
  96                                 throw new MWException( __CLASS__.': invalid value for serializer parameter' );
  97                 }
  98                 $servers = array();
  99                 foreach ( $params['servers'] as $host ) {
 100                         $servers[] = IP::splitHostAndPort( $host ); // (ip, port)
 101                 }
 102                 $this->client->addServers( $servers );
 103         }
 104
 105         /**
 106          * @param $key string
 107          * @return Mixed
 108          */
 109         public function get( $key ) {
 110                 wfProfileIn( __METHOD__ );
 111                 $this->debugLog( "get($key)" );
 112                 $value = $this->checkResult( $key, parent::get( $key ) );
 113                 wfProfileOut( __METHOD__ );
 114                 return $value;
 115         }
 116
 117         /**
 118          * @param $key string
 119          * @param $value
 120          * @param $exptime int
 121          * @return bool
 122          */
 123         public function set( $key, $value, $exptime = 0 ) {
 124                 $this->debugLog( "set($key)" );
 125                 return $this->checkResult( $key, parent::set( $key, $value, $exptime ) );
 126         }
 127
 128         /**
 129          * @param $key string
 130          * @param $time int
 131          * @return bool
 132          */
 133         public function delete( $key, $time = 0 ) {
 134                 $this->debugLog( "delete($key)" );
 135                 $result = parent::delete( $key, $time );
 136                 if ( $result === false && $this->client->getResultCode() === Memcached::RES_NOTFOUND ) {
 137                         // "Not found" is counted as success in our interface
 138                         return true;
 139                 } else {
 140                         return $this->checkResult( $key, $result );
 141                 }
 142         }
 143
 144         /**
 145          * @param $key string
 146          * @param $value int
 147          * @param $exptime int
 148          * @return Mixed
 149          */
 150         public function add( $key, $value, $exptime = 0 ) {
 151                 $this->debugLog( "add($key)" );
 152                 return $this->checkResult( $key, parent::add( $key, $value, $exptime ) );
 153         }
 154
 155         /**
 156          * @param $key string
 157          * @param $value int
 158          * @param $exptime
 159          * @return Mixed
 160          */
 161         public function replace( $key, $value, $exptime = 0 ) {
 162                 $this->debugLog( "replace($key)" );
 163                 return $this->checkResult( $key, parent::replace( $key, $value, $exptime ) );
 164         }
 165
 166         /**
 167          * @param $key string
 168          * @param $value int
 169          * @return Mixed
 170          */
 171         public function incr( $key, $value = 1 ) {
 172                 $this->debugLog( "incr($key)" );
 173                 $result = $this->client->increment( $key, $value );
 174                 return $this->checkResult( $key, $result );
 175         }
 176
 177         /**
 178          * @param $key string
 179          * @param $value int
 180          * @return Mixed
 181          */
 182         public function decr( $key, $value = 1 ) {
 183                 $this->debugLog( "decr($key)" );
 184                 $result = $this->client->decrement( $key, $value );
 185                 return $this->checkResult( $key, $result );
 186         }
 187
 188         /**
 189          * Check the return value from a client method call and take any necessary
 190          * action. Returns the value that the wrapper function should return. At
 191          * present, the return value is always the same as the return value from
 192          * the client, but some day we might find a case where it should be
 193          * different.
 194          *
 195          * @param $key string The key used by the caller, or false if there wasn't one.
 196          * @param $result Mixed The return value
 197          * @return Mixed
 198          */
 199         protected function checkResult( $key, $result ) {
 200                 if ( $result !== false ) {
 201                         return $result;
 202                 }
 203                 switch ( $this->client->getResultCode() ) {
 204                         case Memcached::RES_SUCCESS:
 205                                 break;
 206                         case Memcached::RES_DATA_EXISTS:
 207                         case Memcached::RES_NOTSTORED:
 208                         case Memcached::RES_NOTFOUND:
 209                                 $this->debugLog( "result: " . $this->client->getResultMessage() );
 210                                 break;
 211                         default:
 212                                 $msg = $this->client->getResultMessage();
 213                                 if ( $key !== false ) {
 214                                         $server = $this->client->getServerByKey( $key );
 215                                         $serverName = "{$server['host']}:{$server['port']}";
 216                                         $msg = "Memcached error for key \"$key\" on server \"$serverName\": $msg";
 217                                 } else {
 218                                         $msg = "Memcached error: $msg";
 219                                 }
 220                                 wfDebugLog( 'memcached-serious', $msg );
 221                 }
 222                 return $result;
 223         }
 224
 225         /**
 226          * @param $keys Array
 227          * @return Array
 228          */
 229         public function getMulti( array $keys ) {
 230                 wfProfileIn( __METHOD__ );
 231                 $this->debugLog( 'getMulti(' . implode( ', ', $keys ) . ')' );
 232                 $callback = array( $this, 'encodeKey' );
 233                 $result = $this->client->getMulti( array_map( $callback, $keys ) );
 234                 wfProfileOut( __METHOD__ );
 235                 return $this->checkResult( false, $result );
 236         }
 237
 238         /* NOTE: there is no cas() method here because it is currently not supported
 239          * by the BagOStuff interface and other BagOStuff subclasses, such as
 240          * SqlBagOStuff.
 241          */
 242 }