diff options
author | Pierre Schmitz <pierre@archlinux.de> | 2013-01-18 16:46:04 +0100 |
---|---|---|
committer | Pierre Schmitz <pierre@archlinux.de> | 2013-01-18 16:46:04 +0100 |
commit | 63601400e476c6cf43d985f3e7b9864681695ed4 (patch) | |
tree | f7846203a952e38aaf66989d0a4702779f549962 /includes/objectcache/RedisBagOStuff.php | |
parent | 8ff01378c9e0207f9169b81966a51def645b6a51 (diff) |
Update to MediaWiki 1.20.2
this update includes:
* adjusted Arch Linux skin
* updated FluxBBAuthPlugin
* patch for https://bugzilla.wikimedia.org/show_bug.cgi?id=44024
Diffstat (limited to 'includes/objectcache/RedisBagOStuff.php')
-rw-r--r-- | includes/objectcache/RedisBagOStuff.php | 413 |
1 files changed, 413 insertions, 0 deletions
diff --git a/includes/objectcache/RedisBagOStuff.php b/includes/objectcache/RedisBagOStuff.php new file mode 100644 index 00000000..c5966cdb --- /dev/null +++ b/includes/objectcache/RedisBagOStuff.php @@ -0,0 +1,413 @@ +<?php +/** + * Object caching using Redis (http://redis.io/). + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License along + * with this program; if not, write to the Free Software Foundation, Inc., + * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. + * http://www.gnu.org/copyleft/gpl.html + * + * @file + */ + + +class RedisBagOStuff extends BagOStuff { + protected $connectTimeout, $persistent, $password, $automaticFailover; + + /** + * A list of server names, from $params['servers'] + */ + protected $servers; + + /** + * A cache of Redis objects, representing connections to Redis servers. + * The key is the server name. + */ + protected $conns = array(); + + /** + * An array listing "dead" servers which have had a connection error in + * the past. Servers are marked dead for a limited period of time, to + * avoid excessive overhead from repeated connection timeouts. The key in + * the array is the server name, the value is the UNIX timestamp at which + * the server is resurrected. + */ + protected $deadServers = array(); + + /** + * Construct a RedisBagOStuff object. Parameters are: + * + * - servers: An array of server names. A server name may be a hostname, + * a hostname/port combination or the absolute path of a UNIX socket. + * If a hostname is specified but no port, the standard port number + * 6379 will be used. Required. + * + * - connectTimeout: The timeout for new connections, in seconds. Optional, + * default is 1 second. + * + * - persistent: Set this to true to allow connections to persist across + * multiple web requests. False by default. + * + * - password: The authentication password, will be sent to Redis in + * clear text. Optional, if it is unspecified, no AUTH command will be + * sent. + * + * - automaticFailover: If this is false, then each key will be mapped to + * a single server, and if that server is down, any requests for that key + * will fail. If this is true, a connection failure will cause the client + * to immediately try the next server in the list (as determined by a + * consistent hashing algorithm). True by default. This has the + * potential to create consistency issues if a server is slow enough to + * flap, for example if it is in swap death. + */ + function __construct( $params ) { + if ( !extension_loaded( 'redis' ) ) { + throw new MWException( __CLASS__. ' requires the phpredis extension: ' . + 'https://github.com/nicolasff/phpredis' ); + } + + $this->servers = $params['servers']; + $this->connectTimeout = isset( $params['connectTimeout'] ) + ? $params['connectTimeout'] : 1; + $this->persistent = !empty( $params['persistent'] ); + if ( isset( $params['password'] ) ) { + $this->password = $params['password']; + } + if ( isset( $params['automaticFailover'] ) ) { + $this->automaticFailover = $params['automaticFailover']; + } else { + $this->automaticFailover = true; + } + } + + public function get( $key ) { + wfProfileIn( __METHOD__ ); + list( $server, $conn ) = $this->getConnection( $key ); + if ( !$conn ) { + wfProfileOut( __METHOD__ ); + return false; + } + try { + $result = $conn->get( $key ); + } catch ( RedisException $e ) { + $result = false; + $this->handleException( $server, $e ); + } + $this->logRequest( 'get', $key, $server, $result ); + wfProfileOut( __METHOD__ ); + return $result; + } + + public function set( $key, $value, $expiry = 0 ) { + wfProfileIn( __METHOD__ ); + list( $server, $conn ) = $this->getConnection( $key ); + if ( !$conn ) { + wfProfileOut( __METHOD__ ); + return false; + } + $expiry = $this->convertToRelative( $expiry ); + try { + if ( !$expiry ) { + // No expiry, that is very different from zero expiry in Redis + $result = $conn->set( $key, $value ); + } else { + $result = $conn->setex( $key, $expiry, $value ); + } + } catch ( RedisException $e ) { + $result = false; + $this->handleException( $server, $e ); + } + + $this->logRequest( 'set', $key, $server, $result ); + wfProfileOut( __METHOD__ ); + return $result; + } + + public function delete( $key, $time = 0 ) { + wfProfileIn( __METHOD__ ); + list( $server, $conn ) = $this->getConnection( $key ); + if ( !$conn ) { + wfProfileOut( __METHOD__ ); + return false; + } + try { + $conn->delete( $key ); + // Return true even if the key didn't exist + $result = true; + } catch ( RedisException $e ) { + $result = false; + $this->handleException( $server, $e ); + } + $this->logRequest( 'delete', $key, $server, $result ); + wfProfileOut( __METHOD__ ); + return $result; + } + + public function getMulti( array $keys ) { + wfProfileIn( __METHOD__ ); + $batches = array(); + $conns = array(); + foreach ( $keys as $key ) { + list( $server, $conn ) = $this->getConnection( $key ); + if ( !$conn ) { + continue; + } + $conns[$server] = $conn; + $batches[$server][] = $key; + } + $result = array(); + foreach ( $batches as $server => $batchKeys ) { + $conn = $conns[$server]; + try { + $conn->multi( Redis::PIPELINE ); + foreach ( $batchKeys as $key ) { + $conn->get( $key ); + } + $batchResult = $conn->exec(); + if ( $batchResult === false ) { + $this->debug( "multi request to $server failed" ); + continue; + } + foreach ( $batchResult as $i => $value ) { + if ( $value !== false ) { + $result[$batchKeys[$i]] = $value; + } + } + } catch ( RedisException $e ) { + $this->handleException( $server, $e ); + } + } + + $this->debug( "getMulti for " . count( $keys ) . " keys " . + "returned " . count( $result ) . " results" ); + wfProfileOut( __METHOD__ ); + return $result; + } + + public function add( $key, $value, $expiry = 0 ) { + wfProfileIn( __METHOD__ ); + list( $server, $conn ) = $this->getConnection( $key ); + if ( !$conn ) { + wfProfileOut( __METHOD__ ); + return false; + } + $expiry = $this->convertToRelative( $expiry ); + try { + $result = $conn->setnx( $key, $value ); + if ( $result && $expiry ) { + $conn->expire( $key, $expiry ); + } + } catch ( RedisException $e ) { + $result = false; + $this->handleException( $server, $e ); + } + $this->logRequest( 'add', $key, $server, $result ); + wfProfileOut( __METHOD__ ); + return $result; + } + + /** + * Non-atomic implementation of replace(). Could perhaps be done atomically + * with WATCH or scripting, but this function is rarely used. + */ + public function replace( $key, $value, $expiry = 0 ) { + wfProfileIn( __METHOD__ ); + list( $server, $conn ) = $this->getConnection( $key ); + if ( !$conn ) { + wfProfileOut( __METHOD__ ); + return false; + } + if ( !$conn->exists( $key ) ) { + wfProfileOut( __METHOD__ ); + return false; + } + + $expiry = $this->convertToRelative( $expiry ); + try { + if ( !$expiry ) { + $result = $conn->set( $key, $value ); + } else { + $result = $conn->setex( $key, $expiry, $value ); + } + } catch ( RedisException $e ) { + $result = false; + $this->handleException( $server, $e ); + } + + $this->logRequest( 'replace', $key, $server, $result ); + wfProfileOut( __METHOD__ ); + return $result; + } + + /** + * Non-atomic implementation of incr(). + * + * Probably all callers actually want incr() to atomically initialise + * values to zero if they don't exist, as provided by the Redis INCR + * command. But we are constrained by the memcached-like interface to + * return null in that case. Once the key exists, further increments are + * atomic. + */ + public function incr( $key, $value = 1 ) { + wfProfileIn( __METHOD__ ); + list( $server, $conn ) = $this->getConnection( $key ); + if ( !$conn ) { + wfProfileOut( __METHOD__ ); + return false; + } + if ( !$conn->exists( $key ) ) { + wfProfileOut( __METHOD__ ); + return null; + } + try { + $result = $conn->incrBy( $key, $value ); + } catch ( RedisException $e ) { + $result = false; + $this->handleException( $server, $e ); + } + + $this->logRequest( 'incr', $key, $server, $result ); + wfProfileOut( __METHOD__ ); + return $result; + } + + /** + * Get a Redis object with a connection suitable for fetching the specified key + */ + protected function getConnection( $key ) { + if ( count( $this->servers ) === 1 ) { + $candidates = $this->servers; + } else { + // Use consistent hashing + $hashes = array(); + foreach ( $this->servers as $server ) { + $hashes[$server] = md5( $server . '/' . $key ); + } + asort( $hashes ); + if ( !$this->automaticFailover ) { + reset( $hashes ); + $candidates = array( key( $hashes ) ); + } else { + $candidates = array_keys( $hashes ); + } + } + + foreach ( $candidates as $server ) { + $conn = $this->getConnectionToServer( $server ); + if ( $conn ) { + return array( $server, $conn ); + } + } + return array( false, false ); + } + + /** + * Get a connection to the server with the specified name. Connections + * are cached, and failures are persistent to avoid multiple timeouts. + * + * @return Redis object, or false on failure + */ + protected function getConnectionToServer( $server ) { + if ( isset( $this->deadServers[$server] ) ) { + $now = time(); + if ( $now > $this->deadServers[$server] ) { + // Dead time expired + unset( $this->deadServers[$server] ); + } else { + // Server is dead + $this->debug( "server $server is marked down for another " . + ($this->deadServers[$server] - $now ) . + " seconds, can't get connection" ); + return false; + } + } + + if ( isset( $this->conns[$server] ) ) { + return $this->conns[$server]; + } + + if ( substr( $server, 0, 1 ) === '/' ) { + // UNIX domain socket + // These are required by the redis extension to start with a slash, but + // we still need to set the port to a special value to make it work. + $host = $server; + $port = 0; + } else { + // TCP connection + $hostPort = IP::splitHostAndPort( $server ); + if ( !$hostPort ) { + throw new MWException( __CLASS__.": invalid configured server \"$server\"" ); + } + list( $host, $port ) = $hostPort; + if ( $port === false ) { + $port = 6379; + } + } + $conn = new Redis; + try { + if ( $this->persistent ) { + $this->debug( "opening persistent connection to $host:$port" ); + $result = $conn->pconnect( $host, $port, $this->connectTimeout ); + } else { + $this->debug( "opening non-persistent connection to $host:$port" ); + $result = $conn->connect( $host, $port, $this->connectTimeout ); + } + if ( !$result ) { + $this->logError( "could not connect to server $server" ); + // Mark server down for 30s to avoid further timeouts + $this->deadServers[$server] = time() + 30; + return false; + } + if ( $this->password !== null ) { + if ( !$conn->auth( $this->password ) ) { + $this->logError( "authentication error connecting to $server" ); + } + } + } catch ( RedisException $e ) { + $this->deadServers[$server] = time() + 30; + wfDebugLog( 'redis', "Redis exception: " . $e->getMessage() . "\n" ); + return false; + } + + $conn->setOption( Redis::OPT_SERIALIZER, Redis::SERIALIZER_PHP ); + $this->conns[$server] = $conn; + return $conn; + } + + /** + * Log a fatal error + */ + protected function logError( $msg ) { + wfDebugLog( 'redis', "Redis error: $msg\n" ); + } + + /** + * The redis extension throws an exception in response to various read, write + * and protocol errors. Sometimes it also closes the connection, sometimes + * not. The safest response for us is to explicitly destroy the connection + * object and let it be reopened during the next request. + */ + protected function handleException( $server, $e ) { + wfDebugLog( 'redis', "Redis exception on server $server: " . $e->getMessage() . "\n" ); + unset( $this->conns[$server] ); + } + + /** + * Send information about a single request to the debug log + */ + public function logRequest( $method, $key, $server, $result ) { + $this->debug( "$method $key on $server: " . + ( $result === false ? "failure" : "success" ) ); + } +} + |