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