hadoop TaskUmbilicalProtocol 源码

haddop TaskUmbilicalProtocol 代码

文件路径：/hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-core/src/main/java/org/apache/hadoop/mapred/TaskUmbilicalProtocol.java

/**
 * 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 org.apache.hadoop.classification.InterfaceAudience;
import org.apache.hadoop.classification.InterfaceStability;
import org.apache.hadoop.ipc.VersionedProtocol;
import org.apache.hadoop.mapred.JvmTask;
import org.apache.hadoop.mapreduce.checkpoint.TaskCheckpointID;
import org.apache.hadoop.mapreduce.security.token.JobTokenSelector;
import org.apache.hadoop.security.token.TokenInfo;

/** Protocol that task child process uses to contact its parent process.  The
 * parent is a daemon which which polls the central master for a new map or
 * reduce task and runs it as a child process.  All communication between child
 * and parent is via this protocol. */ 
@TokenInfo(JobTokenSelector.class)
@InterfaceAudience.Private
@InterfaceStability.Stable
public interface TaskUmbilicalProtocol extends VersionedProtocol {

  /** 
   * Changed the version to 2, since we have a new method getMapOutputs 
   * Changed version to 3 to have progress() return a boolean
   * Changed the version to 4, since we have replaced 
   *         TaskUmbilicalProtocol.progress(String, float, String, 
   *         org.apache.hadoop.mapred.TaskStatus.Phase, Counters) 
   *         with statusUpdate(String, TaskStatus)
   * 
   * Version 5 changed counters representation for HADOOP-2248
   * Version 6 changes the TaskStatus representation for HADOOP-2208
   * Version 7 changes the done api (via HADOOP-3140). It now expects whether
   *           or not the task's output needs to be promoted.
   * Version 8 changes {job|tip|task}id's to use their corresponding 
   * objects rather than strings.
   * Version 9 changes the counter representation for HADOOP-1915
   * Version 10 changed the TaskStatus format and added reportNextRecordRange
   *            for HADOOP-153
   * Version 11 Adds RPCs for task commit as part of HADOOP-3150
   * Version 12 getMapCompletionEvents() now also indicates if the events are 
   *            stale or not. Hence the return type is a class that 
   *            encapsulates the events and whether to reset events index.
   * Version 13 changed the getTask method signature for HADOOP-249
   * Version 14 changed the getTask method signature for HADOOP-4232
   * Version 15 Adds FAILED_UNCLEAN and KILLED_UNCLEAN states for HADOOP-4759
   * Version 16 Change in signature of getTask() for HADOOP-5488
   * Version 17 Modified TaskID to be aware of the new TaskTypes
   * Version 18 Added numRequiredSlots to TaskStatus for MAPREDUCE-516
   * Version 19 Added fatalError for child to communicate fatal errors to TT
   * Version 20 Added methods to manage checkpoints
   * Version 21 Added fastFail parameter to fatalError
   * */

  public static final long versionID = 21L;
  
  /**
   * Called when a child task process starts, to get its task.
   * @param context the JvmContext of the JVM w.r.t the TaskTracker that
   *  launched it
   * @return Task object
   * @throws IOException 
   */
  JvmTask getTask(JvmContext context) throws IOException;
  
  /**
   * Report child's progress to parent. Also invoked to report still alive (used
   * to be in ping). It reports an AMFeedback used to propagate preemption requests.
   * 
   * @param taskId task-id of the child
   * @param taskStatus status of the child
   * @throws IOException
   * @throws InterruptedException
   * @return True if the task is known
   */
  AMFeedback statusUpdate(TaskAttemptID taskId, TaskStatus taskStatus) 
  throws IOException, InterruptedException;
  
  /** Report error messages back to parent.  Calls should be sparing, since all
   *  such messages are held in the job tracker.
   *  @param taskid the id of the task involved
   *  @param trace the text to report
   */
  void reportDiagnosticInfo(TaskAttemptID taskid, String trace) throws IOException;
  
  /**
   * Report the record range which is going to process next by the Task.
   * @param taskid the id of the task involved
   * @param range the range of record sequence nos
   * @throws IOException
   */
  void reportNextRecordRange(TaskAttemptID taskid, SortedRanges.Range range) 
    throws IOException;

  /** Report that the task is successfully completed.  Failure is assumed if
   * the task process exits without calling this.
   * @param taskid task's id
   */
  void done(TaskAttemptID taskid) throws IOException;
  
  /** 
   * Report that the task is complete, but its commit is pending.
   * 
   * @param taskId task's id
   * @param taskStatus status of the child
   * @throws IOException
   */
  void commitPending(TaskAttemptID taskId, TaskStatus taskStatus) 
  throws IOException, InterruptedException;  

  /**
   * Polling to know whether the task can go-ahead with commit 
   * @param taskid
   * @return true/false 
   * @throws IOException
   */
  boolean canCommit(TaskAttemptID taskid) throws IOException;

  /** Report that a reduce-task couldn't shuffle map-outputs.*/
  void shuffleError(TaskAttemptID taskId, String message) throws IOException;
  
  /** Report that the task encounted a local filesystem error.*/
  void fsError(TaskAttemptID taskId, String message) throws IOException;

  /**
   * Report that the task encounted a fatal error.
   * @param taskId task's id
   * @param message fail message
   * @param fastFail flag to enable fast fail for task
   */
  void fatalError(TaskAttemptID taskId, String message, boolean fastFail) throws IOException;
  
  /** Called by a reduce task to get the map output locations for finished maps.
   * Returns an update centered around the map-task-completion-events. 
   * The update also piggybacks the information whether the events copy at the 
   * task-tracker has changed or not. This will trigger some action at the 
   * child-process.
   *
   * @param fromIndex the index starting from which the locations should be 
   * fetched
   * @param maxLocs the max number of locations to fetch
   * @param id The attempt id of the task that is trying to communicate
   * @return A {@link MapTaskCompletionEventsUpdate} 
   */
  MapTaskCompletionEventsUpdate getMapCompletionEvents(JobID jobId, 
                                                       int fromIndex, 
                                                       int maxLocs,
                                                       TaskAttemptID id) 
  throws IOException;

  /**
   * Report to the AM that the task has been succesfully preempted.
   *
   * @param taskId task's id
   * @param taskStatus status of the child
   * @throws IOException
   */
  void preempted(TaskAttemptID taskId, TaskStatus taskStatus)
      throws IOException, InterruptedException;

  /**
   * Return the latest CheckpointID for the given TaskID. This provides
   * the task with a way to locate the checkpointed data and restart from
   * that point in the computation.
   *
   * @param taskID task's id
   * @return the most recent checkpoint (if any) for this task
   */
  TaskCheckpointID getCheckpointID(TaskID taskID);

  /**
   * Send a CheckpointID for a given TaskID to be stored in the AM,
   * to later restart a task from this checkpoint.
   * @param tid
   * @param cid
   */
  void setCheckpointID(TaskID tid, TaskCheckpointID cid);

}

相关信息

hadoop 源码目录

相关文章

hadoop AMFeedback 源码

hadoop BackupStore 源码

hadoop BasicTypeSorterBase 源码

hadoop BufferSorter 源码

hadoop CleanupQueue 源码

hadoop Clock 源码

hadoop ClusterStatus 源码

hadoop Counters 源码

hadoop CumulativePeriodicStats 源码

hadoop DeprecatedQueueConfigurationParser 源码