RedisBagOStuff.php

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<?php
class RedisBagOStuff extends BagOStuff {
        protected $redisPool;
        protected $servers;
        protected $automaticFailover;

        function __construct( $params ) {
                $redisConf = array( 'serializer' => 'php' );
                foreach ( array( 'connectTimeout', 'persistent', 'password' ) as $opt ) {
                        if ( isset( $params[$opt] ) ) {
                                $redisConf[$opt] = $params[$opt];
                        }
                }
                $this->redisPool = RedisConnectionPool::singleton( $redisConf );

                $this->servers = $params['servers'];
                if ( isset( $params['automaticFailover'] ) ) {
                        $this->automaticFailover = $params['automaticFailover'];
                } else {
                        $this->automaticFailover = true;
                }
        }

        public function get( $key, &$casToken = null ) {
                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, $conn, $e );
                }
                $casToken = $result;
                $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, $conn, $e );
                }

                $this->logRequest( 'set', $key, $server, $result );
                wfProfileOut( __METHOD__ );
                return $result;
        }

        public function cas( $casToken, $key, $value, $expiry = 0 ) {
                wfProfileIn( __METHOD__ );
                list( $server, $conn ) = $this->getConnection( $key );
                if ( !$conn ) {
                        wfProfileOut( __METHOD__ );
                        return false;
                }
                $expiry = $this->convertToRelative( $expiry );
                try {
                        $conn->watch( $key );

                        if ( $this->get( $key ) !== $casToken ) {
                                wfProfileOut( __METHOD__ );
                                return false;
                        }

                        $conn->multi();

                        if ( !$expiry ) {
                                // No expiry, that is very different from zero expiry in Redis
                                $conn->set( $key, $value );
                        } else {
                                $conn->setex( $key, $expiry, $value );
                        }

                        $result = $conn->exec();
                } catch ( RedisException $e ) {
                        $result = false;
                        $this->handleException( $server, $conn, $e );
                }

                $this->logRequest( 'cas', $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, $conn, $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, $conn, $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, $conn, $e );
                }
                $this->logRequest( 'add', $key, $server, $result );
                wfProfileOut( __METHOD__ );
                return $result;
        }

        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, $conn, $e );
                }

                $this->logRequest( 'replace', $key, $server, $result );
                wfProfileOut( __METHOD__ );
                return $result;
        }

        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, $conn, $e );
                }

                $this->logRequest( 'incr', $key, $server, $result );
                wfProfileOut( __METHOD__ );
                return $result;
        }

        protected function getConnection( $key ) {
                if ( count( $this->servers ) === 1 ) {
                        $candidates = $this->servers;
                } else {
                        $candidates = $this->servers;
                        ArrayUtils::consistentHashSort( $candidates, $key, '/' );
                        if ( !$this->automaticFailover ) {
                                $candidates = array_slice( $candidates, 0, 1 );
                        }
                }

                foreach ( $candidates as $server ) {
                        $conn = $this->redisPool->getConnection( $server );
                        if ( $conn ) {
                                return array( $server, $conn );
                        }
                }
                return array( false, false );
        }

        protected function logError( $msg ) {
                wfDebugLog( 'redis', "Redis error: $msg\n" );
        }

        protected function handleException( $server, RedisConnRef $conn, $e ) {
                $this->redisPool->handleException( $server, $conn, $e );
        }

        public function logRequest( $method, $key, $server, $result ) {
                $this->debug( "$method $key on $server: " .
                        ( $result === false ? "failure" : "success" ) );
        }
}