org.apache.hadoop.hdfs.shortcircuit.DomainSocketFactory.java Source code

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Here is the source code for org.apache.hadoop.hdfs.shortcircuit.DomainSocketFactory.java

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/**
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.apache.hadoop.hdfs.shortcircuit;

import java.io.IOException;
import java.net.InetSocketAddress;
import java.util.concurrent.TimeUnit;

import org.apache.commons.io.IOUtils;
import org.apache.commons.logging.Log;
import org.apache.hadoop.HadoopIllegalArgumentException;
import org.apache.hadoop.hdfs.DFSClient.Conf;
import org.apache.hadoop.net.unix.DomainSocket;

import com.google.common.base.Preconditions;
import com.google.common.cache.Cache;
import com.google.common.cache.CacheBuilder;
import org.apache.commons.logging.LogFactory;
import org.apache.hadoop.hdfs.DFSClient;
import org.apache.hadoop.hdfs.DFSConfigKeys;
import org.apache.hadoop.util.PerformanceAdvisory;

public class DomainSocketFactory {
    private static final Log LOG = LogFactory.getLog(DomainSocketFactory.class);

    public enum PathState {
        UNUSABLE(false, false), SHORT_CIRCUIT_DISABLED(true, false), VALID(true, true);

        PathState(boolean usableForDataTransfer, boolean usableForShortCircuit) {
            this.usableForDataTransfer = usableForDataTransfer;
            this.usableForShortCircuit = usableForShortCircuit;
        }

        public boolean getUsableForDataTransfer() {
            return usableForDataTransfer;
        }

        public boolean getUsableForShortCircuit() {
            return usableForShortCircuit;
        }

        private final boolean usableForDataTransfer;
        private final boolean usableForShortCircuit;
    }

    public static class PathInfo {
        private final static PathInfo NOT_CONFIGURED = new PathInfo("", PathState.UNUSABLE);

        final private String path;
        final private PathState state;

        PathInfo(String path, PathState state) {
            this.path = path;
            this.state = state;
        }

        public String getPath() {
            return path;
        }

        public PathState getPathState() {
            return state;
        }

        @Override
        public String toString() {
            return new StringBuilder().append("PathInfo{path=").append(path).append(", state=").append(state)
                    .append("}").toString();
        }
    }

    /**
     * Information about domain socket paths.
     */
    Cache<String, PathState> pathMap = CacheBuilder.newBuilder().expireAfterWrite(10, TimeUnit.MINUTES).build();

    public DomainSocketFactory(Conf conf) {
        final String feature;
        if (conf.isShortCircuitLocalReads() && (!conf.isUseLegacyBlockReaderLocal())) {
            feature = "The short-circuit local reads feature";
        } else if (conf.isDomainSocketDataTraffic()) {
            feature = "UNIX domain socket data traffic";
        } else {
            feature = null;
        }

        if (feature == null) {
            PerformanceAdvisory.LOG.debug("Both short-circuit local reads and UNIX domain socket are disabled.");
        } else {
            if (conf.getDomainSocketPath().isEmpty()) {
                throw new HadoopIllegalArgumentException(
                        feature + " is enabled but " + DFSConfigKeys.DFS_DOMAIN_SOCKET_PATH_KEY + " is not set.");
            } else if (DomainSocket.getLoadingFailureReason() != null) {
                LOG.warn(feature + " cannot be used because " + DomainSocket.getLoadingFailureReason());
            } else {
                LOG.debug(feature + " is enabled.");
            }
        }
    }

    /**
     * Get information about a domain socket path.
     *
     * @param addr         The inet address to use.
     * @param conf         The client configuration.
     *
     * @return             Information about the socket path.
     */
    public PathInfo getPathInfo(InetSocketAddress addr, DFSClient.Conf conf) {
        // If there is no domain socket path configured, we can't use domain
        // sockets.
        if (conf.getDomainSocketPath().isEmpty())
            return PathInfo.NOT_CONFIGURED;
        // If we can't do anything with the domain socket, don't create it.
        if (!conf.isDomainSocketDataTraffic()
                && (!conf.isShortCircuitLocalReads() || conf.isUseLegacyBlockReaderLocal())) {
            return PathInfo.NOT_CONFIGURED;
        }
        // If the DomainSocket code is not loaded, we can't create
        // DomainSocket objects.
        if (DomainSocket.getLoadingFailureReason() != null) {
            return PathInfo.NOT_CONFIGURED;
        }
        // UNIX domain sockets can only be used to talk to local peers
        if (!DFSClient.isLocalAddress(addr))
            return PathInfo.NOT_CONFIGURED;
        String escapedPath = DomainSocket.getEffectivePath(conf.getDomainSocketPath(), addr.getPort());
        PathState status = pathMap.getIfPresent(escapedPath);
        if (status == null) {
            return new PathInfo(escapedPath, PathState.VALID);
        } else {
            return new PathInfo(escapedPath, status);
        }
    }

    public DomainSocket createSocket(PathInfo info, int socketTimeout) {
        Preconditions.checkArgument(info.getPathState() != PathState.UNUSABLE);
        boolean success = false;
        DomainSocket sock = null;
        try {
            sock = DomainSocket.connect(info.getPath());
            sock.setAttribute(DomainSocket.RECEIVE_TIMEOUT, socketTimeout);
            success = true;
        } catch (IOException e) {
            LOG.warn("error creating DomainSocket", e);
            // fall through
        } finally {
            if (!success) {
                if (sock != null) {
                    IOUtils.closeQuietly(sock);
                }
                pathMap.put(info.getPath(), PathState.UNUSABLE);
                sock = null;
            }
        }
        return sock;
    }

    public void disableShortCircuitForPath(String path) {
        pathMap.put(path, PathState.SHORT_CIRCUIT_DISABLED);
    }

    public void disableDomainSocketPath(String path) {
        pathMap.put(path, PathState.UNUSABLE);
    }
}