org.apache.hadoop.yarn.client.ConfiguredFailoverProxyProvider.java Source code

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Here is the source code for org.apache.hadoop.yarn.client.ConfiguredFailoverProxyProvider.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.yarn.client;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.hadoop.classification.InterfaceAudience;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.io.retry.FailoverProxyProvider;
import org.apache.hadoop.security.UserGroupInformation;
import org.apache.hadoop.yarn.conf.HAUtil;
import org.apache.hadoop.yarn.conf.YarnConfiguration;
import org.apache.hadoop.yarn.ipc.YarnRPC;

import java.io.IOException;
import java.net.InetSocketAddress;
import java.security.PrivilegedAction;

@InterfaceAudience.Private
public abstract class ConfiguredFailoverProxyProvider<T> implements FailoverProxyProvider<T> {
    private static final Log LOG = LogFactory.getLog(ConfiguredFailoverProxyProvider.class);

    private int currentProxyIndex = 0;
    private final String[] rmServiceIds;
    protected final Class<T> protocol;
    protected final YarnConfiguration conf;

    public ConfiguredFailoverProxyProvider(Configuration configuration, Class<T> protocol) {
        checkAllowedProtocols(protocol);
        this.conf = new YarnConfiguration(configuration);
        this.protocol = protocol;
        this.rmServiceIds = HAUtil.getRMHAIds(conf).toArray(new String[2]);
    }

    public abstract void checkAllowedProtocols(Class<T> protocol);

    public abstract InetSocketAddress getRMAddress() throws IOException;

    @Override
    public T getProxy() {
        UserGroupInformation ugi;
        final InetSocketAddress rmAddress;
        try {
            ugi = UserGroupInformation.getCurrentUser();
            rmAddress = getRMAddress();
            if (LOG.isTraceEnabled()) {
                LOG.trace("Connecting to RM at " + rmAddress);
            }
        } catch (IOException ioe) {
            return null;
        }

        if (ugi == null) {
            return null;
        }

        return ugi.doAs(new PrivilegedAction<T>() {
            @Override
            public T run() {
                return (T) YarnRPC.create(conf).getProxy(protocol, rmAddress, conf);
            }
        });
    }

    @Override
    public void performFailover(T currentProxy) {
        if (LOG.isTraceEnabled()) {
            LOG.trace("Performing failover " + currentProxyIndex);
        }
        currentProxyIndex = (currentProxyIndex + 1) % rmServiceIds.length;
        conf.set(YarnConfiguration.RM_HA_ID, rmServiceIds[currentProxyIndex]);
        if (LOG.isTraceEnabled()) {
            LOG.trace("Performed failover to RM " + rmServiceIds[currentProxyIndex]);
        }
    }

    @Override
    public Class<T> getInterface() {
        return protocol;
    }

    @Override
    public void close() throws IOException {
        // do nothing
    }
}