TaskController (Hadoop 1.2.1 API)
Date: 2013-07-22

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## org.apache.hadoop.mapred
Class TaskController

    java.lang.Object
      org.apache.hadoop.mapred.TaskController

All Implemented Interfaces:
  Configurable

Direct Known Subclasses:
  DefaultTaskController

    public abstract class TaskController

extends Object
implements Configurable

Controls initialization, finalization and clean up of tasks, and also the launching and killing of task JVMs. This class defines the API for initializing, finalizing and cleaning up of tasks, as also the launching and killing task JVMs. Subclasses of this class will implement the logic required for performing the actual actions.
NOTE: This class is internal only class and not intended for users!!

Field Summary
`protected LocalDirAllocator` | `allocator`
`protected static String` | `COMMAND_FILE`
`protected org.apache.hadoop.mapred.TaskTracker.LocalStorage` | `localStorage`
`static org.apache.commons.logging.Log` | `LOG`
`static FsPermission` | `TASK_LAUNCH_SCRIPT_PERMISSION`

Constructor Summary
`TaskController()`

Method Summary
`abstract void` | `createLogDir(TaskAttemptID taskID, boolean isCleanup)` Creates task log dir
`abstract void` | `deleteAsUser(String user, String subDir)` Delete the user's files under all of the task tracker root directories.
`abstract void` | `deleteLogAsUser(String user, String subDir)` Delete the user's files under the userlogs directory.
`Configuration` | `getConf()` Return the configuration used by this object.
`String[]` | `getLocalDirs()`
`String` | `getRunAsUser(JobConf conf)` Returns the local unix user that a given job will run as.
`abstract void` | `initializeJob(String user, String jobid, Path credentials, Path jobConf, TaskUmbilicalProtocol taskTracker, InetSocketAddress ttAddr)` Create all of the directories necessary for the job to start and download all of the job and private distributed cache files.
`abstract int` | `launchTask(String user, String jobId, String attemptId, List<String> setup, List<String> jvmArguments, File currentWorkDirectory, String stdout, String stderr)` Create all of the directories for the task and launches the child jvm.
`protected void` | `logOutput(String output)`
`void` | `setConf(Configuration conf)` Set the configuration to be used by this object.
`abstract void` | `setup(LocalDirAllocator allocator, org.apache.hadoop.mapred.TaskTracker.LocalStorage localStorage)` Does initialization and setup.
`abstract void` | `signalTask(String user, int taskPid, ProcessTree.Signal signal)` Send a signal to a task pid as the user.
`abstract void` | `truncateLogsAsUser(String user, List<Task> allAttempts)` Run the passed command as the user
`protected static String` | `writeCommand(String cmdLine, FileSystem fs, Path commandFile)`

Methods inherited from class java.lang.Object
`clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`

Field Detail

### LOG

    public static final org.apache.commons.logging.Log LOG

### COMMAND_FILE

    protected static final String COMMAND_FILE

See Also:
  Constant Field Values

### allocator

    protected LocalDirAllocator allocator

### localStorage

    protected org.apache.hadoop.mapred.TaskTracker.LocalStorage localStorage

### TASK_LAUNCH_SCRIPT_PERMISSION

    public static final FsPermission TASK_LAUNCH_SCRIPT_PERMISSION

Constructor Detail

### TaskController

    public TaskController()

Method Detail

### getConf

    public Configuration getConf()

  Description copied from interface: `Configurable`
  Return the configuration used by this object.

  Specified by:
    `getConf` in interface `Configurable`

### getLocalDirs

    public String[] getLocalDirs()

### setConf

    public void setConf(Configuration conf)

  Description copied from interface: `Configurable`
  Set the configuration to be used by this object.

  Specified by:
    `setConf` in interface `Configurable`

### setup

    public abstract void setup(LocalDirAllocator allocator,
                               org.apache.hadoop.mapred.TaskTracker.LocalStorage localStorage)
                        throws IOException

  Does initialization and setup.

  Parameters:
    `allocator` - the local dir allocator to use
    `localStorage` - local storage to obtain dirs from
  Throws:
    `IOException`

### initializeJob

    public abstract void initializeJob(String user,
                                       String jobid,
                                       Path credentials,
                                       Path jobConf,
                                       TaskUmbilicalProtocol taskTracker,
                                       InetSocketAddress ttAddr)
                                throws IOException,
                                       InterruptedException

  Create all of the directories necessary for the job to start and download all of the job and private distributed cache files. Creates both the user directories and the job log directory.

  Parameters:
    `user` - the user name
    `jobid` - the job
    `credentials` - a filename containing the job secrets
    `jobConf` - the path to the localized configuration file
    `taskTracker` - the connection the task tracker
    `ttAddr` - the tasktracker's RPC address
  Throws:
    `IOException`
    `InterruptedException`

### launchTask

    public abstract int launchTask(String user,
                                   String jobId,
                                   String attemptId,
                                   List<String> setup,
                                   List<String> jvmArguments,
                                   File currentWorkDirectory,
                                   String stdout,
                                   String stderr)
                            throws IOException

  Create all of the directories for the task and launches the child jvm.

  Parameters:
    `user` - the user name
    `jobId` - the jobId in question
    `attemptId` - the attempt id (cleanup attempts have .cleanup suffix)
    `setup` - list of shell commands to execute before the jvm
    `jvmArguments` - list of jvm arguments
    `currentWorkDirectory` - the full path of the cwd for the task
    `stdout` - the file to redirect stdout to
    `stderr` - the file to redirect stderr to
  Returns:
    the exit code for the task
  Throws:
    `IOException`

### signalTask

    public abstract void signalTask(String user,
                                    int taskPid,
                                    ProcessTree.Signal signal)
                             throws IOException

  Send a signal to a task pid as the user.

  Parameters:
    `user` - the user name
    `taskPid` - the pid of the task
    `signal` - the id of the signal to send
  Throws:
    `IOException`

### deleteAsUser

    public abstract void deleteAsUser(String user,
                                      String subDir)
                               throws IOException

  Delete the user's files under all of the task tracker root directories.

  Parameters:
    `user` - the user name
    `subDir` - the path relative to the user's subdirectory under the task tracker root directories.
  Throws:
    `IOException`

### createLogDir

    public abstract void createLogDir(TaskAttemptID taskID,
                                      boolean isCleanup)
                               throws IOException

  Creates task log dir

  Parameters:
    `taskID` - ID of the task
    `isCleanup` - If the task is cleanup task or not
  Throws:
    `IOException`

### deleteLogAsUser

    public abstract void deleteLogAsUser(String user,
                                         String subDir)
                                  throws IOException

  Delete the user's files under the userlogs directory.

  Parameters:
    `user` - the user to work as
    `subDir` - the path under the userlogs directory.
  Throws:
    `IOException`

### truncateLogsAsUser

    public abstract void truncateLogsAsUser(String user,
                                            List<Task> allAttempts)
                                     throws IOException

  Run the passed command as the user

  Parameters:
    `user` -
    `allAttempts` - the list of attempts that the JVM ran
  Throws:
    `IOException`

### getRunAsUser

    public String getRunAsUser(JobConf conf)

  Returns the local unix user that a given job will run as.

### writeCommand

    protected static String writeCommand(String cmdLine,
                                         FileSystem fs,
                                         Path commandFile)
                                  throws IOException

  Throws:
    `IOException`

### logOutput

    protected void logOutput(String output)

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