content: /*
   * 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.spark.network.shuffle.mesos;
  
  import java.io.IOException;
  import java.nio.ByteBuffer;
  import java.util.concurrent.Executors;
  import java.util.concurrent.ScheduledExecutorService;
  import java.util.concurrent.TimeUnit;
  
  import com.google.common.util.concurrent.ThreadFactoryBuilder;
  import org.apache.spark.network.shuffle.protocol.mesos.ShuffleServiceHeartbeat;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  import org.apache.spark.network.client.RpcResponseCallback;
  import org.apache.spark.network.client.TransportClient;
  import org.apache.spark.network.sasl.SecretKeyHolder;
  import org.apache.spark.network.shuffle.ExternalShuffleClient;
  import org.apache.spark.network.shuffle.protocol.mesos.RegisterDriver;
  import org.apache.spark.network.util.TransportConf;
  
  /**
   * A client for talking to the external shuffle service in Mesos coarse-grained mode.
   *
   * This is used by the Spark driver to register with each external shuffle service on the cluster.
   * The reason why the driver has to talk to the service is for cleaning up shuffle files reliably
   * after the application exits. Mesos does not provide a great alternative to do this, so Spark
   * has to detect this itself.
   */
  public class MesosExternalShuffleClient extends ExternalShuffleClient {
    private static final Logger logger = LoggerFactory.getLogger(MesosExternalShuffleClient.class);
  
    private final ScheduledExecutorService heartbeaterThread =
        Executors.newSingleThreadScheduledExecutor(
          new ThreadFactoryBuilder()
            .setDaemon(true)
            .setNameFormat("mesos-external-shuffle-client-heartbeater")
            .build());
  
    /**
     * Creates an Mesos external shuffle client that wraps the {@link ExternalShuffleClient}.
     * Please refer to docs on {@link ExternalShuffleClient} for more information.
     */
    public MesosExternalShuffleClient(
        TransportConf conf,
        SecretKeyHolder secretKeyHolder,
        boolean saslEnabled,
        boolean saslEncryptionEnabled) {
      super(conf, secretKeyHolder, saslEnabled, saslEncryptionEnabled);
    }
  
    public void registerDriverWithShuffleService(
        String host,
        int port,
        long heartbeatTimeoutMs,
        long heartbeatIntervalMs) throws IOException {
  
      checkInit();
      ByteBuffer registerDriver = new RegisterDriver(appId, heartbeatTimeoutMs).toByteBuffer();
      TransportClient client = clientFactory.createClient(host, port);
      client.sendRpc(registerDriver, new RegisterDriverCallback(client, heartbeatIntervalMs));
    }
  
    private class RegisterDriverCallback implements RpcResponseCallback {
      private final TransportClient client;
      private final long heartbeatIntervalMs;
  
      private RegisterDriverCallback(TransportClient client, long heartbeatIntervalMs) {
        this.client = client;
        this.heartbeatIntervalMs = heartbeatIntervalMs;
      }
  
      @Override
      public void onSuccess(ByteBuffer response) {
        heartbeaterThread.scheduleAtFixedRate(
            new Heartbeater(client), 0, heartbeatIntervalMs, TimeUnit.MILLISECONDS);
        logger.info("Successfully registered app " + appId + " with external shuffle service.");
      }
  
      @Override
      public void onFailure(Throwable e) {
        logger.warn("Unable to register app " + appId + " with external shuffle service. " +
            "Please manually remove shuffle data after driver exit. Error: " + e);
      }
    }
  
    @Override
    public void close() {
      heartbeaterThread.shutdownNow();
      super.close();
    }
  
    private class Heartbeater implements Runnable {
  
      private final TransportClient client;
  
      private Heartbeater(TransportClient client) {
        this.client = client;
      }
  
      @Override
      public void run() {
        // TODO: Stop sending heartbeats if the shuffle service has lost the app due to timeout
        client.send(new ShuffleServiceHeartbeat(appId).toByteBuffer());
      }
    }
  }
  