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          *   - retry_timeout:       Time in seconds to wait before retrying a failed connect attempt
  41          *   - server_failure_limit:  Limit for server connect failures before it is removed
  42          *   - serializer:          May be either "php" or "igbinary". Igbinary produces more compact
  43          *                          values, but serialization is much slower unless the php.ini option
  44          *                          igbinary.compact_strings is off.
  45          */
  46         function __construct( $params ) {
  47                 $params = $this->applyDefaultParams( $params );
  48
  49                 if ( $params['persistent'] ) {
  50                         // The pool ID must be unique to the server/option combination.
  51                         // The Memcached object is essentially shared for each pool ID.
  52                         // We can only reuse a pool ID if we keep the config consistent.
  53                         $this->client = new Memcached( md5( serialize( $params ) ) );
  54                         if ( count( $this->client->getServerList() ) ) {
  55                                 wfDebug( __METHOD__ . ": persistent Memcached object already loaded.\n" );
  56                                 return; // already initialized; don't add duplicate servers
  57                         }
  58                 } else {
  59                         $this->client = new Memcached;
  60                 }
  61
  62                 if ( !isset( $params['serializer'] ) ) {
  63                         $params['serializer'] = 'php';
  64                 }
  65
  66                 if ( isset( $params['retry_timeout'] ) ) {
  67                         $this->client->setOption( Memcached::OPT_RETRY_TIMEOUT, $params['retry_timeout'] );
  68                 }
  69
  70                 if ( isset( $params['server_failure_limit'] ) ) {
  71                         $this->client->setOption( Memcached::OPT_SERVER_FAILURE_LIMIT, $params['server_failure_limit'] );
  72                 }
  73
  74                 // The compression threshold is an undocumented php.ini option for some
  75                 // reason. There's probably not much harm in setting it globally, for
  76                 // compatibility with the settings for the PHP client.
  77                 ini_set( 'memcached.compression_threshold', $params['compress_threshold'] );
  78
  79                 // Set timeouts
  80                 $this->client->setOption( Memcached::OPT_CONNECT_TIMEOUT, $params['connect_timeout'] * 1000 );
  81                 $this->client->setOption( Memcached::OPT_SEND_TIMEOUT, $params['timeout'] );
  82                 $this->client->setOption( Memcached::OPT_RECV_TIMEOUT, $params['timeout'] );
  83                 $this->client->setOption( Memcached::OPT_POLL_TIMEOUT, $params['timeout'] / 1000 );
  84
  85                 // Set libketama mode since it's recommended by the documentation and
  86                 // is as good as any. There's no way to configure libmemcached to use
  87                 // hashes identical to the ones currently in use by the PHP client, and
  88                 // even implementing one of the libmemcached hashes in pure PHP for
  89                 // forwards compatibility would require MWMemcached::get_sock() to be
  90                 // rewritten.
  91                 $this->client->setOption( Memcached::OPT_LIBKETAMA_COMPATIBLE, true );
  92
  93                 // Set the serializer
  94                 switch ( $params['serializer'] ) {
  95                         case 'php':
  96                                 $this->client->setOption( Memcached::OPT_SERIALIZER, Memcached::SERIALIZER_PHP );
  97                                 break;
  98                         case 'igbinary':
  99                                 if ( !Memcached::HAVE_IGBINARY ) {
 100                                         throw new MWException( __CLASS__ . ': the igbinary extension is not available ' .
 101                                                 'but igbinary serialization was requested.' );
 102                                 }
 103                                 $this->client->setOption( Memcached::OPT_SERIALIZER, Memcached::SERIALIZER_IGBINARY );
 104                                 break;
 105                         default:
 106                                 throw new MWException( __CLASS__ . ': invalid value for serializer parameter' );
 107                 }
 108                 $servers = array();
 109                 foreach ( $params['servers'] as $host ) {
 110                         $servers[] = IP::splitHostAndPort( $host ); // (ip, port)
 111                 }
 112                 $this->client->addServers( $servers );
 113         }
 114
 115         /**
 116          * @param $key string
 117          * @param $casToken[optional] float
 118          * @return Mixed
 119          */
 120         public function get( $key, &$casToken = null ) {
 121                 wfProfileIn( __METHOD__ );
 122                 $this->debugLog( "get($key)" );
 123                 $result = $this->client->get( $this->encodeKey( $key ), null, $casToken );
 124                 $result = $this->checkResult( $key, $result );
 125                 wfProfileOut( __METHOD__ );
 126                 return $result;
 127         }
 128
 129         /**
 130          * @param $key string
 131          * @param $value
 132          * @param $exptime int
 133          * @return bool
 134          */
 135         public function set( $key, $value, $exptime = 0 ) {
 136                 $this->debugLog( "set($key)" );
 137                 return $this->checkResult( $key, parent::set( $key, $value, $exptime ) );
 138         }
 139
 140         /**
 141          * @param $casToken float
 142          * @param $key string
 143          * @param $value
 144          * @param $exptime int
 145          * @return bool
 146          */
 147         public function cas( $casToken, $key, $value, $exptime = 0 ) {
 148                 $this->debugLog( "cas($key)" );
 149                 return $this->checkResult( $key, parent::cas( $casToken, $key, $value, $exptime ) );
 150         }
 151
 152         /**
 153          * @param $key string
 154          * @param $time int
 155          * @return bool
 156          */
 157         public function delete( $key, $time = 0 ) {
 158                 $this->debugLog( "delete($key)" );
 159                 $result = parent::delete( $key, $time );
 160                 if ( $result === false && $this->client->getResultCode() === Memcached::RES_NOTFOUND ) {
 161                         // "Not found" is counted as success in our interface
 162                         return true;
 163                 } else {
 164                         return $this->checkResult( $key, $result );
 165                 }
 166         }
 167
 168         /**
 169          * @param $key string
 170          * @param $value int
 171          * @param $exptime int
 172          * @return Mixed
 173          */
 174         public function add( $key, $value, $exptime = 0 ) {
 175                 $this->debugLog( "add($key)" );
 176                 return $this->checkResult( $key, parent::add( $key, $value, $exptime ) );
 177         }
 178
 179         /**
 180          * @param $key string
 181          * @param $value int
 182          * @return Mixed
 183          */
 184         public function incr( $key, $value = 1 ) {
 185                 $this->debugLog( "incr($key)" );
 186                 $result = $this->client->increment( $key, $value );
 187                 return $this->checkResult( $key, $result );
 188         }
 189
 190         /**
 191          * @param $key string
 192          * @param $value int
 193          * @return Mixed
 194          */
 195         public function decr( $key, $value = 1 ) {
 196                 $this->debugLog( "decr($key)" );
 197                 $result = $this->client->decrement( $key, $value );
 198                 return $this->checkResult( $key, $result );
 199         }
 200
 201         /**
 202          * Check the return value from a client method call and take any necessary
 203          * action. Returns the value that the wrapper function should return. At
 204          * present, the return value is always the same as the return value from
 205          * the client, but some day we might find a case where it should be
 206          * different.
 207          *
 208          * @param string $key The key used by the caller, or false if there wasn't one.
 209          * @param $result Mixed The return value
 210          * @return Mixed
 211          */
 212         protected function checkResult( $key, $result ) {
 213                 if ( $result !== false ) {
 214                         return $result;
 215                 }
 216                 switch ( $this->client->getResultCode() ) {
 217                         case Memcached::RES_SUCCESS:
 218                                 break;
 219                         case Memcached::RES_DATA_EXISTS:
 220                         case Memcached::RES_NOTSTORED:
 221                         case Memcached::RES_NOTFOUND:
 222                                 $this->debugLog( "result: " . $this->client->getResultMessage() );
 223                                 break;
 224                         default:
 225                                 $msg = $this->client->getResultMessage();
 226                                 if ( $key !== false ) {
 227                                         $server = $this->client->getServerByKey( $key );
 228                                         $serverName = "{$server['host']}:{$server['port']}";
 229                                         $msg = "Memcached error for key \"$key\" on server \"$serverName\": $msg";
 230                                 } else {
 231                                         $msg = "Memcached error: $msg";
 232                                 }
 233                                 wfDebugLog( 'memcached-serious', $msg );
 234                 }
 235                 return $result;
 236         }
 237
 238         /**
 239          * @param $keys Array
 240          * @return Array
 241          */
 242         public function getMulti( array $keys ) {
 243                 wfProfileIn( __METHOD__ );
 244                 $this->debugLog( 'getMulti(' . implode( ', ', $keys ) . ')' );
 245                 $callback = array( $this, 'encodeKey' );
 246                 $result = $this->client->getMulti( array_map( $callback, $keys ) );
 247                 wfProfileOut( __METHOD__ );
 248                 return $this->checkResult( false, $result );
 249         }
 250
 251         /* NOTE: there is no cas() method here because it is currently not supported
 252          * by the BagOStuff interface and other BagOStuff subclasses, such as
 253          * SqlBagOStuff.
 254          */
 255 }