org.apache.sentry.hdfs.ha.HdfsHAClientInvocationHandler.java Source code

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Here is the source code for org.apache.sentry.hdfs.ha.HdfsHAClientInvocationHandler.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.sentry.hdfs.ha;

import java.io.IOException;
import java.lang.reflect.InvocationHandler;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.net.InetSocketAddress;

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.security.SecurityUtil;
import org.apache.curator.x.discovery.ServiceInstance;
import org.apache.sentry.hdfs.SentryHDFSServiceClientDefaultImpl;
import org.apache.sentry.hdfs.SentryHdfsServiceException;
import org.apache.sentry.hdfs.ServiceConstants;
import org.apache.sentry.provider.db.service.persistent.HAContext;
import org.apache.sentry.provider.db.service.persistent.ServiceManager;
import org.apache.sentry.service.thrift.ServiceConstants.ServerConfig;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import com.google.common.base.Preconditions;

public class HdfsHAClientInvocationHandler implements InvocationHandler {

    private static final Logger LOGGER = LoggerFactory.getLogger(HdfsHAClientInvocationHandler.class);

    private final Configuration conf;
    private ServiceManager manager;
    private ServiceInstance<Void> currentServiceInstance;
    private SentryHDFSServiceClientDefaultImpl client = null;

    private static final String THRIFT_EXCEPTION_MESSAGE = "Thrift exception occured ";
    public static final String SENTRY_HA_ERROR_MESSAGE = "No Sentry server available. "
            + "Please ensure that at least one Sentry server is online";

    public HdfsHAClientInvocationHandler(Configuration conf) throws Exception {
        this.conf = conf;
        checkClientConf();
    }

    @Override
    public Object invoke(Object proxy, Method method, Object[] args) throws SentryHdfsServiceException {
        Object result = null;
        while (true) {
            try {
                if (!method.isAccessible()) {
                    method.setAccessible(true);
                }
                // The client is initialized in the first call instead of constructor.
                // This way we can propagate the connection exception to caller cleanly
                if (client == null) {
                    renewSentryClient();
                }
                result = method.invoke(client, args);
            } catch (IllegalAccessException e) {
                throw new SentryHdfsServiceException(e.getMessage(), e.getCause());
            } catch (InvocationTargetException e) {
                if (!(e.getTargetException() instanceof SentryHdfsServiceException)) {
                    throw new SentryHdfsServiceException("Error in Sentry HDFS client", e.getTargetException());
                } else {
                    LOGGER.warn(THRIFT_EXCEPTION_MESSAGE + ": Error in connect current"
                            + " service, will retry other service.", e);
                    if (client != null) {
                        client.close();
                        client = null;
                    }
                    throw (SentryHdfsServiceException) e.getTargetException();
                }
            } catch (IOException e1) {
                // close() doesn't throw exception we supress that in case of connection
                // loss. Changing SentryPolicyServiceClient#close() to throw an
                // exception would be a backward incompatible change for Sentry clients.
                if ("close".equals(method.getName())) {
                    return null;
                }
                throw new SentryHdfsServiceException("Error connecting to sentry service " + e1.getMessage(), e1);
            }
            return result;
        }
    }

    // Retrieve the new connection endpoint from ZK and connect to new server
    private void renewSentryClient() throws IOException {
        try {
            manager = new ServiceManager(HAContext.getHAContext(conf));
        } catch (Exception e1) {
            throw new IOException("Failed to extract Sentry node info from zookeeper", e1);
        }

        try {
            while (true) {
                currentServiceInstance = manager.getServiceInstance();
                if (currentServiceInstance == null) {
                    throw new IOException(SENTRY_HA_ERROR_MESSAGE);
                }
                InetSocketAddress serverAddress = ServiceManager.convertServiceInstance(currentServiceInstance);
                conf.set(ServiceConstants.ClientConfig.SERVER_RPC_ADDRESS, serverAddress.getHostName());
                conf.setInt(ServiceConstants.ClientConfig.SERVER_RPC_PORT, serverAddress.getPort());
                try {
                    client = new SentryHDFSServiceClientDefaultImpl(conf);
                    LOGGER.info("Sentry Client using server " + serverAddress.getHostName() + ":"
                            + serverAddress.getPort());
                    break;
                } catch (IOException e) {
                    manager.reportError(currentServiceInstance);
                    LOGGER.info("Transport exception while opening transport:", e, e.getMessage());
                }
            }
        } finally {
            manager.close();
        }
    }

    private void checkClientConf() {
        if (conf.getBoolean(ServerConfig.SENTRY_HA_ZOOKEEPER_SECURITY,
                ServerConfig.SENTRY_HA_ZOOKEEPER_SECURITY_DEFAULT)) {
            String serverPrincipal = Preconditions.checkNotNull(conf.get(ServerConfig.PRINCIPAL),
                    ServerConfig.PRINCIPAL + " is required");
            Preconditions.checkArgument(serverPrincipal.contains(SecurityUtil.HOSTNAME_PATTERN),
                    ServerConfig.PRINCIPAL + " : " + serverPrincipal + " should contain "
                            + SecurityUtil.HOSTNAME_PATTERN);
        }
    }
}