alluxio.cli.fs.command.LeaderCommand.java Source code

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Here is the source code for alluxio.cli.fs.command.LeaderCommand.java

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/*
 * The Alluxio Open Foundation licenses this work under the Apache License, version 2.0
 * (the "License"). You may not use this work except in compliance with the License, which is
 * available at www.apache.org/licenses/LICENSE-2.0
 *
 * This software is distributed on an "AS IS" basis, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,
 * either express or implied, as more fully set forth in the License.
 *
 * See the NOTICE file distributed with this work for information regarding copyright ownership.
 */

package alluxio.cli.fs.command;

import alluxio.cli.CommandUtils;
import alluxio.client.file.FileSystem;
import alluxio.client.file.FileSystemContext;
import alluxio.client.file.FileSystemMasterClient;
import alluxio.exception.status.InvalidArgumentException;
import alluxio.exception.status.UnavailableException;
import alluxio.master.MasterInquireClient;
import alluxio.master.PollingMasterInquireClient;
import alluxio.resource.CloseableResource;
import alluxio.retry.ExponentialBackoffRetry;

import org.apache.commons.cli.CommandLine;

import java.net.InetSocketAddress;
import java.util.Arrays;
import java.util.List;

import javax.annotation.concurrent.ThreadSafe;

/**
 * Prints the current leader master host name.
 */
@ThreadSafe
public final class LeaderCommand extends AbstractFileSystemCommand {

    /**
     * @param fs the filesystem of Alluxio
     */
    public LeaderCommand(FileSystem fs) {
        super(fs);
    }

    @Override
    public String getCommandName() {
        return "leader";
    }

    @Override
    public void validateArgs(CommandLine cl) throws InvalidArgumentException {
        CommandUtils.checkNumOfArgsEquals(this, cl, 0);
    }

    @Override
    public int run(CommandLine cl) {
        try (CloseableResource<FileSystemMasterClient> client = FileSystemContext.INSTANCE
                .acquireMasterClientResource()) {
            try {
                InetSocketAddress address = client.get().getAddress();
                System.out.println(address.getHostName());

                List<InetSocketAddress> addresses = Arrays.asList(address);
                MasterInquireClient inquireClient = new PollingMasterInquireClient(addresses,
                        () -> new ExponentialBackoffRetry(50, 100, 2));
                try {
                    inquireClient.getPrimaryRpcAddress();
                } catch (UnavailableException e) {
                    System.err.println("The leader is not currently serving requests.");
                }
            } catch (UnavailableException e) {
                System.err.println("Failed to get the leader master.");
            }
        }
        return 0;
    }

    @Override
    public String getUsage() {
        return "leader";
    }

    @Override
    public String getDescription() {
        return "Prints the current leader master host name.";
    }
}