/**
* 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.mapred;

import java.io.IOException;
import java.net.InetSocketAddress;
import java.util.ArrayList;
import java.util.Collections;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.ipc.ProtocolSignature;
import org.apache.hadoop.ipc.RPC;
import org.apache.hadoop.ipc.RPC.Server;
import org.apache.hadoop.ipc.VersionedProtocol;
import org.apache.hadoop.mapred.SortedRanges.Range;
import org.apache.hadoop.mapreduce.TypeConverter;
import org.apache.hadoop.mapreduce.security.token.JobTokenSecretManager;
import org.apache.hadoop.mapreduce.v2.api.records.TaskType;
import org.apache.hadoop.mapreduce.v2.app.AMConstants;
import org.apache.hadoop.mapreduce.v2.app.AppContext;
import org.apache.hadoop.mapreduce.v2.app.TaskAttemptListener;
import org.apache.hadoop.mapreduce.v2.app.TaskHeartbeatHandler;
import org.apache.hadoop.mapreduce.v2.app.job.Job;
import org.apache.hadoop.mapreduce.v2.app.job.Task;
import org.apache.hadoop.mapreduce.v2.app.job.event.TaskAttemptDiagnosticsUpdateEvent;
import org.apache.hadoop.mapreduce.v2.app.job.event.TaskAttemptEvent;
import org.apache.hadoop.mapreduce.v2.app.job.event.TaskAttemptEventType;
import org.apache.hadoop.mapreduce.v2.app.job.event.TaskAttemptStatusUpdateEvent;
import org.apache.hadoop.mapreduce.v2.app.job.event.TaskAttemptStatusUpdateEvent.TaskAttemptStatus;
import org.apache.hadoop.net.NetUtils;
import org.apache.hadoop.yarn.YarnException;
import org.apache.hadoop.yarn.service.CompositeService;

/**
 * This class is responsible for talking to the task umblical.
 * It also converts all the old data structures
 * to yarn data structures.
 * 
 * This class HAS to be in this package to access package private 
 * methods/classes.
 */
public class TaskAttemptListenerImpl extends CompositeService 
    implements TaskUmbilicalProtocol, TaskAttemptListener {

  private static final Log LOG = LogFactory.getLog(TaskAttemptListenerImpl.class);

  private AppContext context;
  private Server server;
  private TaskHeartbeatHandler taskHeartbeatHandler;
  private InetSocketAddress address;
  private Map<WrappedJvmID, org.apache.hadoop.mapred.Task> jvmIDToAttemptMap = 
    Collections.synchronizedMap(new HashMap<WrappedJvmID, 
        org.apache.hadoop.mapred.Task>());
  private JobTokenSecretManager jobTokenSecretManager = null;
  
  public TaskAttemptListenerImpl(AppContext context,
      JobTokenSecretManager jobTokenSecretManager) {
    super(TaskAttemptListenerImpl.class.getName());
    this.context = context;
    this.jobTokenSecretManager = jobTokenSecretManager;
  }

  @Override
  public void init(Configuration conf) {
   registerHeartbeatHandler();
   super.init(conf);
  }

  @Override
  public void start() {
    startRpcServer();
    super.start();
  }

  protected void registerHeartbeatHandler() {
    taskHeartbeatHandler = new TaskHeartbeatHandler(context.getEventHandler(), 
        context.getClock());
    addService(taskHeartbeatHandler);
  }

  protected void startRpcServer() {
    Configuration conf = getConfig();
    try {
      server =
          RPC.getServer(TaskUmbilicalProtocol.class, this, "0.0.0.0", 0, 
              conf.getInt(AMConstants.AM_TASK_LISTENER_THREADS, 
                  AMConstants.DEFAULT_AM_TASK_LISTENER_THREADS),
              false, conf, jobTokenSecretManager);
      server.start();
      InetSocketAddress listenerAddress = server.getListenerAddress();
      this.address =
          NetUtils.createSocketAddr(listenerAddress.getAddress()
              .getLocalHost().getCanonicalHostName()
              + ":" + listenerAddress.getPort());
    } catch (IOException e) {
      throw new YarnException(e);
    }
  }

  @Override
  public void stop() {
    stopRpcServer();
    super.stop();
  }

  protected void stopRpcServer() {
    server.stop();
  }

  @Override
  public InetSocketAddress getAddress() {
    return address;
  }

  /**
   * Child checking whether it can commit.
   * 
   * <br/>
   * Commit is a two-phased protocol. First the attempt informs the
   * ApplicationMaster that it is
   * {@link #commitPending(TaskAttemptID, TaskStatus)}. Then it repeatedly polls
   * the ApplicationMaster whether it {@link #canCommit(TaskAttemptID)} This is
   * a legacy from the centralized commit protocol handling by the JobTracker.
   */
  @Override
  public boolean canCommit(TaskAttemptID taskAttemptID) throws IOException {
    LOG.info("Commit go/no-go request from " + taskAttemptID.toString());
    // An attempt is asking if it can commit its output. This can be decided
    // only by the task which is managing the multiple attempts. So redirect the
    // request there.
    org.apache.hadoop.mapreduce.v2.api.records.TaskAttemptId attemptID =
        TypeConverter.toYarn(taskAttemptID);

    taskHeartbeatHandler.receivedPing(attemptID);

    Job job = context.getJob(attemptID.getTaskId().getJobId());
    Task task = job.getTask(attemptID.getTaskId());
    return task.canCommit(attemptID);
  }

  /**
   * TaskAttempt is reporting that it is in commit_pending and it is waiting for
   * the commit Response
   * 
   * <br/>
   * Commit it a two-phased protocol. First the attempt informs the
   * ApplicationMaster that it is
   * {@link #commitPending(TaskAttemptID, TaskStatus)}. Then it repeatedly polls
   * the ApplicationMaster whether it {@link #canCommit(TaskAttemptID)} This is
   * a legacy from the centralized commit protocol handling by the JobTracker.
   */
  @Override
  public void commitPending(TaskAttemptID taskAttemptID, TaskStatus taskStatsu)
          throws IOException, InterruptedException {
    LOG.info("Commit-pending state update from " + taskAttemptID.toString());
    // An attempt is asking if it can commit its output. This can be decided
    // only by the task which is managing the multiple attempts. So redirect the
    // request there.
    org.apache.hadoop.mapreduce.v2.api.records.TaskAttemptId attemptID =
        TypeConverter.toYarn(taskAttemptID);

    taskHeartbeatHandler.receivedPing(attemptID);
    //Ignorable TaskStatus? - since a task will send a LastStatusUpdate
    context.getEventHandler().handle(
        new TaskAttemptEvent(attemptID, 
            TaskAttemptEventType.TA_COMMIT_PENDING));
  }

  @Override
  public void done(TaskAttemptID taskAttemptID) throws IOException {
    LOG.info("Done acknowledgement from " + taskAttemptID.toString());

    org.apache.hadoop.mapreduce.v2.api.records.TaskAttemptId attemptID =
        TypeConverter.toYarn(taskAttemptID);

    taskHeartbeatHandler.receivedPing(attemptID);

    context.getEventHandler().handle(
        new TaskAttemptEvent(attemptID, TaskAttemptEventType.TA_DONE));
  }

  @Override
  public void fatalError(TaskAttemptID taskAttemptID, String msg)
      throws IOException {
    // This happens only in Child and in the Task.
    LOG.fatal("Task: " + taskAttemptID + " - exited : " + msg);
    reportDiagnosticInfo(taskAttemptID, "Error: " + msg);

    org.apache.hadoop.mapreduce.v2.api.records.TaskAttemptId attemptID =
        TypeConverter.toYarn(taskAttemptID);
    context.getEventHandler().handle(
        new TaskAttemptEvent(attemptID, TaskAttemptEventType.TA_FAILMSG));
  }

  @Override
  public void fsError(TaskAttemptID taskAttemptID, String message)
      throws IOException {
    // This happens only in Child.
    LOG.fatal("Task: " + taskAttemptID + " - failed due to FSError: "
        + message);
    reportDiagnosticInfo(taskAttemptID, "FSError: " + message);

    org.apache.hadoop.mapreduce.v2.api.records.TaskAttemptId attemptID =
        TypeConverter.toYarn(taskAttemptID);
    context.getEventHandler().handle(
        new TaskAttemptEvent(attemptID, TaskAttemptEventType.TA_FAILMSG));
  }

  @Override
  public void shuffleError(TaskAttemptID taskAttemptID, String message) throws IOException {
    // TODO: This isn't really used in any MR code. Ask for removal.    
  }

  @Override
  public MapTaskCompletionEventsUpdate getMapCompletionEvents(
      JobID jobIdentifier, int fromEventId, int maxEvents,
      TaskAttemptID taskAttemptID) throws IOException {
    LOG.info("MapCompletionEvents request from " + taskAttemptID.toString()
        + ". fromEventID " + fromEventId + " maxEvents " + maxEvents);

    // TODO: shouldReset is never used. See TT. Ask for Removal.
    boolean shouldReset = false;
    org.apache.hadoop.mapreduce.v2.api.records.TaskAttemptId attemptID =
      TypeConverter.toYarn(taskAttemptID);
    org.apache.hadoop.mapreduce.v2.api.records.TaskAttemptCompletionEvent[] events =
        context.getJob(attemptID.getTaskId().getJobId()).getTaskAttemptCompletionEvents(
            fromEventId, maxEvents);

    taskHeartbeatHandler.receivedPing(attemptID);

    // filter the events to return only map completion events in old format
    List<TaskCompletionEvent> mapEvents = new ArrayList<TaskCompletionEvent>();
    for (org.apache.hadoop.mapreduce.v2.api.records.TaskAttemptCompletionEvent event : events) {
      if (TaskType.MAP.equals(event.getAttemptId().getTaskId().getTaskType())) {
        mapEvents.add(TypeConverter.fromYarn(event));
      }
    }
    
    return new MapTaskCompletionEventsUpdate(
        mapEvents.toArray(new TaskCompletionEvent[0]), shouldReset);
  }

  @Override
  public boolean ping(TaskAttemptID taskAttemptID) throws IOException {
    LOG.info("Ping from " + taskAttemptID.toString());
    taskHeartbeatHandler.receivedPing(TypeConverter.toYarn(taskAttemptID));
    return true;
  }

  @Override
  public void reportDiagnosticInfo(TaskAttemptID taskAttemptID, String diagnosticInfo)
 throws IOException {
    LOG.info("Diagnostics report from " + taskAttemptID.toString() + ": "
        + diagnosticInfo);

    org.apache.hadoop.mapreduce.v2.api.records.TaskAttemptId attemptID =
      TypeConverter.toYarn(taskAttemptID);
    taskHeartbeatHandler.receivedPing(attemptID);

    // This is mainly used for cases where we want to propagate exception traces
    // of tasks that fail.

    // This call exists as a hadoop mapreduce legacy wherein all changes in
    // counters/progress/phase/output-size are reported through statusUpdate()
    // call but not diagnosticInformation.
    context.getEventHandler().handle(
        new TaskAttemptDiagnosticsUpdateEvent(attemptID, diagnosticInfo));
  }

  @Override
  public boolean statusUpdate(TaskAttemptID taskAttemptID,
      TaskStatus taskStatus) throws IOException, InterruptedException {
    LOG.info("Status update from " + taskAttemptID.toString());
    org.apache.hadoop.mapreduce.v2.api.records.TaskAttemptId yarnAttemptID =
        TypeConverter.toYarn(taskAttemptID);
    taskHeartbeatHandler.receivedPing(yarnAttemptID);
    TaskAttemptStatus taskAttemptStatus =
        new TaskAttemptStatus();
    taskAttemptStatus.id = yarnAttemptID;
    // Task sends the updated progress to the TT.
    taskAttemptStatus.progress = taskStatus.getProgress();
    LOG.info("Progress of TaskAttempt " + taskAttemptID + " is : "
        + taskStatus.getProgress());
    // Task sends the diagnostic information to the TT
    taskAttemptStatus.diagnosticInfo = taskStatus.getDiagnosticInfo();
    // Task sends the updated state-string to the TT.
    taskAttemptStatus.stateString = taskStatus.getStateString();
    // Set the output-size when map-task finishes. Set by the task itself.
    taskAttemptStatus.outputSize = taskStatus.getOutputSize();
    // Task sends the updated phase to the TT.
    taskAttemptStatus.phase = TypeConverter.toYarn(taskStatus.getPhase());
    // Counters are updated by the task.
    taskAttemptStatus.counters =
        TypeConverter.toYarn(taskStatus.getCounters());

    // Map Finish time set by the task (map only)
    if (taskStatus.getIsMap() && taskStatus.getMapFinishTime() != 0) {
      taskAttemptStatus.mapFinishTime = taskStatus.getMapFinishTime();
    }

    // Shuffle Finish time set by the task (reduce only).
    if (!taskStatus.getIsMap() && taskStatus.getShuffleFinishTime() != 0) {
      taskAttemptStatus.shuffleFinishTime = taskStatus.getShuffleFinishTime();
    }

    // Sort finish time set by the task (reduce only).
    if (!taskStatus.getIsMap() && taskStatus.getSortFinishTime() != 0) {
      taskAttemptStatus.sortFinishTime = taskStatus.getSortFinishTime();
    }

    // Not Setting the task state. Used by speculation - will be set in TaskAttemptImpl
    //taskAttemptStatus.taskState =  TypeConverter.toYarn(taskStatus.getRunState());
    
    //set the fetch failures
    if (taskStatus.getFetchFailedMaps() != null 
        && taskStatus.getFetchFailedMaps().size() > 0) {
      taskAttemptStatus.fetchFailedMaps = 
        new ArrayList<org.apache.hadoop.mapreduce.v2.api.records.TaskAttemptId>();
      for (TaskAttemptID failedMapId : taskStatus.getFetchFailedMaps()) {
        taskAttemptStatus.fetchFailedMaps.add(
            TypeConverter.toYarn(failedMapId));
      }
    }

 // Task sends the information about the nextRecordRange to the TT
    
//    TODO: The following are not needed here, but needed to be set somewhere inside AppMaster.
//    taskStatus.getRunState(); // Set by the TT/JT. Transform into a state TODO
//    taskStatus.getStartTime(); // Used to be set by the TaskTracker. This should be set by getTask().
//    taskStatus.getFinishTime(); // Used to be set by TT/JT. Should be set when task finishes
//    // This was used by TT to do counter updates only once every minute. So this
//    // isn't ever changed by the Task itself.
//    taskStatus.getIncludeCounters();

    context.getEventHandler().handle(
        new TaskAttemptStatusUpdateEvent(taskAttemptStatus.id,
            taskAttemptStatus));
    return true;
  }

  @Override
  public long getProtocolVersion(String arg0, long arg1) throws IOException {
    return TaskUmbilicalProtocol.versionID;
  }

  @Override
  public void reportNextRecordRange(TaskAttemptID taskAttemptID, Range range)
      throws IOException {
    // This is used when the feature of skipping records is enabled.

    // This call exists as a hadoop mapreduce legacy wherein all changes in
    // counters/progress/phase/output-size are reported through statusUpdate()
    // call but not the next record range information.
    throw new IOException("Not yet implemented.");
  }

  @Override
  public JvmTask getTask(JvmContext context) throws IOException {

    // A rough imitation of code from TaskTracker.

    JVMId jvmId = context.jvmId;
    LOG.info("JVM with ID : " + jvmId + " asked for a task");

    // TODO: Is it an authorised container to get a task? Otherwise return null.

    // TODO: Is the request for task-launch still valid?

    // TODO: Child.java's firstTaskID isn't really firstTaskID. Ask for update
    // to jobId and task-type.

    WrappedJvmID wJvmID = new WrappedJvmID(jvmId.getJobId(), jvmId.isMap,
        jvmId.getId());
    org.apache.hadoop.mapred.Task task = jvmIDToAttemptMap.get(wJvmID);
    if (task != null) { //there may be lag in the attempt getting added here
      LOG.info("JVM with ID: " + jvmId + " given task: " + task.getTaskID());
      JvmTask jvmTask = new JvmTask(task, false);
      
      //remove the task as it is no more needed and free up the memory
      jvmIDToAttemptMap.remove(wJvmID);
      
      return jvmTask;
    }
    return null;
  }

  @Override
  public void register(org.apache.hadoop.mapreduce.v2.api.records.TaskAttemptId attemptID,
      org.apache.hadoop.mapred.Task task, WrappedJvmID jvmID) {
    //create the mapping so that it is easy to look up
    //when it comes back to ask for Task.
    jvmIDToAttemptMap.put(jvmID, task);
    //register this attempt
    taskHeartbeatHandler.register(attemptID);
  }

  @Override
  public void unregister(org.apache.hadoop.mapreduce.v2.api.records.TaskAttemptId attemptID,
      WrappedJvmID jvmID) {
    //remove the mapping if not already removed
    jvmIDToAttemptMap.remove(jvmID);

    //unregister this attempt
    taskHeartbeatHandler.unregister(attemptID);
  }

  @Override
  public ProtocolSignature getProtocolSignature(String protocol,
      long clientVersion, int clientMethodsHash) throws IOException {
    return ProtocolSignature.getProtocolSignature(this, 
        protocol, clientVersion, clientMethodsHash);
  }
}