content: /*
   * 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.job.command;
  
  import alluxio.annotation.PublicApi;
  import alluxio.cli.CommandUtils;
  import alluxio.cli.fs.command.AbstractFileSystemCommand;
  import alluxio.client.file.FileSystemContext;
  import alluxio.client.job.JobContext;
  import alluxio.exception.status.InvalidArgumentException;
  
  import org.apache.commons.cli.CommandLine;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  import java.net.InetSocketAddress;
  import javax.annotation.concurrent.ThreadSafe;
  
  /**
   * Prints the current leader master host name.
   */
  @ThreadSafe
  @PublicApi
  public final class LeaderCommand extends AbstractFileSystemCommand {
    private static final Logger LOG = LoggerFactory.getLogger(LeaderCommand.class);
  
    /**
     * creates the job leader command.
     *
     * @param fsContext the Alluxio filesystem client
     */
    public LeaderCommand(FileSystemContext fsContext) {
      super(fsContext);
    }
  
    @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 {
        InetSocketAddress address = JobContext
            .create(mFsContext.getClusterConf(), mFsContext.getClientContext().getUserState())
            .getJobMasterAddress();
        System.out.println(address.getHostName());
      } catch (Exception e) {
        LOG.error("Failed to get the primary job master", e);
        System.out.println("Failed to get the primary job master.");
        return -1;
      }
      return 0;
    }
  
    @Override
    public String getUsage() {
      return "leader";
    }
  
    @Override
    public String getDescription() {
      return "Prints the hostname of the job master service leader.";
    }
  }
  