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          * @param array $params
  46          */
  47         function __construct( $params ) {
  48                 $params = $this->applyDefaultParams( $params );
  49
  50                 if ( $params['persistent'] ) {
  51                         // The pool ID must be unique to the server/option combination.
  52                         // The Memcached object is essentially shared for each pool ID.
  53                         // We can only reuse a pool ID if we keep the config consistent.
  54                         $this->client = new Memcached( md5( serialize( $params ) ) );
  55                         if ( count( $this->client->getServerList() ) ) {
  56                                 wfDebug( __METHOD__ . ": persistent Memcached object already loaded.\n" );
  57                                 return; // already initialized; don't add duplicate servers
  58                         }
  59                 } else {
  60                         $this->client = new Memcached;
  61                 }
  62
  63                 if ( !isset( $params['serializer'] ) ) {
  64                         $params['serializer'] = 'php';
  65                 }
  66
  67                 if ( isset( $params['retry_timeout'] ) ) {
  68                         $this->client->setOption( Memcached::OPT_RETRY_TIMEOUT, $params['retry_timeout'] );
  69                 }
  70
  71                 if ( isset( $params['server_failure_limit'] ) ) {
  72                         $this->client->setOption( Memcached::OPT_SERVER_FAILURE_LIMIT, $params['server_failure_limit'] );
  73                 }
  74
  75                 // The compression threshold is an undocumented php.ini option for some
  76                 // reason. There's probably not much harm in setting it globally, for
  77                 // compatibility with the settings for the PHP client.
  78                 ini_set( 'memcached.compression_threshold', $params['compress_threshold'] );
  79
  80                 // Set timeouts
  81                 $this->client->setOption( Memcached::OPT_CONNECT_TIMEOUT, $params['connect_timeout'] * 1000 );
  82                 $this->client->setOption( Memcached::OPT_SEND_TIMEOUT, $params['timeout'] );
  83                 $this->client->setOption( Memcached::OPT_RECV_TIMEOUT, $params['timeout'] );
  84                 $this->client->setOption( Memcached::OPT_POLL_TIMEOUT, $params['timeout'] / 1000 );
  85
  86                 // Set libketama mode since it's recommended by the documentation and
  87                 // is as good as any. There's no way to configure libmemcached to use
  88                 // hashes identical to the ones currently in use by the PHP client, and
  89                 // even implementing one of the libmemcached hashes in pure PHP for
  90                 // forwards compatibility would require MWMemcached::get_sock() to be
  91                 // rewritten.
  92                 $this->client->setOption( Memcached::OPT_LIBKETAMA_COMPATIBLE, true );
  93
  94                 // Set the serializer
  95                 switch ( $params['serializer'] ) {
  96                         case 'php':
  97                                 $this->client->setOption( Memcached::OPT_SERIALIZER, Memcached::SERIALIZER_PHP );
  98                                 break;
  99                         case 'igbinary':
 100                                 if ( !Memcached::HAVE_IGBINARY ) {
 101                                         throw new MWException( __CLASS__ . ': the igbinary extension is not available ' .
 102                                                 'but igbinary serialization was requested.' );
 103                                 }
 104                                 $this->client->setOption( Memcached::OPT_SERIALIZER, Memcached::SERIALIZER_IGBINARY );
 105                                 break;
 106                         default:
 107                                 throw new MWException( __CLASS__ . ': invalid value for serializer parameter' );
 108                 }
 109                 $servers = array();
 110                 foreach ( $params['servers'] as $host ) {
 111                         $servers[] = IP::splitHostAndPort( $host ); // (ip, port)
 112                 }
 113                 $this->client->addServers( $servers );
 114         }
 115
 116         /**
 117          * @param string $key
 118          * @param float $casToken [optional]
 119          * @return mixed
 120          */
 121         public function get( $key, &$casToken = null ) {
 122                 wfProfileIn( __METHOD__ );
 123                 $this->debugLog( "get($key)" );
 124                 $result = $this->client->get( $this->encodeKey( $key ), null, $casToken );
 125                 $result = $this->checkResult( $key, $result );
 126                 wfProfileOut( __METHOD__ );
 127                 return $result;
 128         }
 129
 130         /**
 131          * @param string $key
 132          * @param mixed $value
 133          * @param int $exptime
 134          * @return bool
 135          */
 136         public function set( $key, $value, $exptime = 0 ) {
 137                 $this->debugLog( "set($key)" );
 138                 return $this->checkResult( $key, parent::set( $key, $value, $exptime ) );
 139         }
 140
 141         /**
 142          * @param float $casToken
 143          * @param string $key
 144          * @param mixed $value
 145          * @param int $exptime
 146          * @return bool
 147          */
 148         public function cas( $casToken, $key, $value, $exptime = 0 ) {
 149                 $this->debugLog( "cas($key)" );
 150                 return $this->checkResult( $key, parent::cas( $casToken, $key, $value, $exptime ) );
 151         }
 152
 153         /**
 154          * @param string $key
 155          * @param int $time
 156          * @return bool
 157          */
 158         public function delete( $key, $time = 0 ) {
 159                 $this->debugLog( "delete($key)" );
 160                 $result = parent::delete( $key, $time );
 161                 if ( $result === false && $this->client->getResultCode() === Memcached::RES_NOTFOUND ) {
 162                         // "Not found" is counted as success in our interface
 163                         return true;
 164                 } else {
 165                         return $this->checkResult( $key, $result );
 166                 }
 167         }
 168
 169         /**
 170          * @param string $key
 171          * @param int $value
 172          * @param int $exptime
 173          * @return mixed
 174          */
 175         public function add( $key, $value, $exptime = 0 ) {
 176                 $this->debugLog( "add($key)" );
 177                 return $this->checkResult( $key, parent::add( $key, $value, $exptime ) );
 178         }
 179
 180         /**
 181          * @param string $key
 182          * @param int $value
 183          * @return mixed
 184          */
 185         public function incr( $key, $value = 1 ) {
 186                 $this->debugLog( "incr($key)" );
 187                 $result = $this->client->increment( $key, $value );
 188                 return $this->checkResult( $key, $result );
 189         }
 190
 191         /**
 192          * @param string $key
 193          * @param int $value
 194          * @return mixed
 195          */
 196         public function decr( $key, $value = 1 ) {
 197                 $this->debugLog( "decr($key)" );
 198                 $result = $this->client->decrement( $key, $value );
 199                 return $this->checkResult( $key, $result );
 200         }
 201
 202         /**
 203          * Check the return value from a client method call and take any necessary
 204          * action. Returns the value that the wrapper function should return. At
 205          * present, the return value is always the same as the return value from
 206          * the client, but some day we might find a case where it should be
 207          * different.
 208          *
 209          * @param string $key The key used by the caller, or false if there wasn't one.
 210          * @param mixed $result The return value
 211          * @return mixed
 212          */
 213         protected function checkResult( $key, $result ) {
 214                 if ( $result !== false ) {
 215                         return $result;
 216                 }
 217                 switch ( $this->client->getResultCode() ) {
 218                         case Memcached::RES_SUCCESS:
 219                                 break;
 220                         case Memcached::RES_DATA_EXISTS:
 221                         case Memcached::RES_NOTSTORED:
 222                         case Memcached::RES_NOTFOUND:
 223                                 $this->debugLog( "result: " . $this->client->getResultMessage() );
 224                                 break;
 225                         default:
 226                                 $msg = $this->client->getResultMessage();
 227                                 if ( $key !== false ) {
 228                                         $server = $this->client->getServerByKey( $key );
 229                                         $serverName = "{$server['host']}:{$server['port']}";
 230                                         $msg = "Memcached error for key \"$key\" on server \"$serverName\": $msg";
 231                                 } else {
 232                                         $msg = "Memcached error: $msg";
 233                                 }
 234                                 wfDebugLog( 'memcached-serious', $msg );
 235                                 $this->setLastError( BagOStuff::ERR_UNEXPECTED );
 236                 }
 237                 return $result;
 238         }
 239
 240         /**
 241          * @param array $keys
 242          * @return array
 243          */
 244         public function getMulti( array $keys ) {
 245                 wfProfileIn( __METHOD__ );
 246                 $this->debugLog( 'getMulti(' . implode( ', ', $keys ) . ')' );
 247                 $callback = array( $this, 'encodeKey' );
 248                 $result = $this->client->getMulti( array_map( $callback, $keys ) );
 249                 wfProfileOut( __METHOD__ );
 250                 return $this->checkResult( false, $result );
 251         }
 252
 253         /**
 254          * @param array $data
 255          * @param int $exptime
 256          * @return bool
 257          */
 258         public function setMulti( array $data, $exptime = 0 ) {
 259                 wfProfileIn( __METHOD__ );
 260                 foreach ( $data as $key => $value ) {
 261                         $encKey = $this->encodeKey( $key );
 262                         if ( $encKey !== $key ) {
 263                                 $data[$encKey] = $value;
 264                                 unset( $data[$key] );
 265                         }
 266                 }
 267                 $this->debugLog( 'setMulti(' . implode( ', ', array_keys( $data ) ) . ')' );
 268                 $result = $this->client->setMulti( $data, $this->fixExpiry( $exptime ) );
 269                 wfProfileOut( __METHOD__ );
 270                 return $this->checkResult( false, $result );
 271         }
 272
 273
 274         /* NOTE: there is no cas() method here because it is currently not supported
 275          * by the BagOStuff interface and other BagOStuff subclasses, such as
 276          * SqlBagOStuff.
 277          */
 278 }