java.lang.Object
- org.apache.flink.runtime.taskmanager.Task

All Implemented Interfaces:

Runnable, PartitionProducerStateProvider, TaskSlotPayload, TaskActions
```
public class Task
extends Object
implements Runnable, TaskSlotPayload, TaskActions, PartitionProducerStateProvider
```
The Task represents one execution of a parallel subtask on a TaskManager. A Task wraps a Flink operator (which may be a user function) and runs it, providing all services necessary for example to consume input data, produce its results (intermediate result partitions) and communicate with the JobManager.
The Flink operators (implemented as subclasses of TaskInvokable have only data readers, writers, and certain event callbacks. The task connects those to the network stack and actor messages, and tracks the state of the execution and handles exceptions.
Tasks have no knowledge about how they relate to other tasks, or whether they are the first attempt to execute the task, or a repeated attempt. All of that is only known to the JobManager. All the task knows are its own runnable code, the task's configuration, and the IDs of the intermediate results to consume and produce (if any).
Each Task is run by one dedicated thread.

Nested Class Summary

Nested Classes
Modifier and Type Class Description

static class Task.NotifyCheckpointOperation
Various operation of notify checkpoint.
- Nested classes/interfaces inherited from interface org.apache.flink.runtime.io.network.partition.PartitionProducerStateProvider
  PartitionProducerStateProvider.ResponseHandle

Constructor Summary

Constructors
Constructor	Description
Task(JobInformation jobInformation, TaskInformation taskInformation, ExecutionAttemptID executionAttemptID, AllocationID slotAllocationId, List<ResultPartitionDeploymentDescriptor> resultPartitionDeploymentDescriptors, List<InputGateDeploymentDescriptor> inputGateDeploymentDescriptors, MemoryManager memManager, SharedResources sharedResources, IOManager ioManager, ShuffleEnvironment<?,?> shuffleEnvironment, KvStateService kvStateService, BroadcastVariableManager bcVarManager, TaskEventDispatcher taskEventDispatcher, ExternalResourceInfoProvider externalResourceInfoProvider, TaskStateManager taskStateManager, TaskManagerActions taskManagerActions, InputSplitProvider inputSplitProvider, CheckpointResponder checkpointResponder, TaskOperatorEventGateway operatorCoordinatorEventGateway, GlobalAggregateManager aggregateManager, LibraryCacheManager.ClassLoaderHandle classLoaderHandle, FileCache fileCache, TaskManagerRuntimeInfo taskManagerConfig, TaskMetricGroup metricGroup, PartitionProducerStateChecker partitionProducerStateChecker, Executor executor, ChannelStateWriteRequestExecutorFactory channelStateExecutorFactory)	IMPORTANT: This constructor may not start any work that would need to be undone in the case of a failing task deployment.

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`void`	`cancelExecution()`	Cancels the task execution.
`void`	`deliverOperatorEvent(OperatorID operator, SerializedValue<OperatorEvent> evt)`	Dispatches an operator event to the invokable task.
`void`	`failExternally(Throwable cause)`	Marks task execution failed for an external reason (a reason other than the task code itself throwing an exception).
`AccumulatorRegistry`	`getAccumulatorRegistry()`
`AllocationID`	`getAllocationId()`
`Thread`	`getExecutingThread()`
`ExecutionAttemptID`	`getExecutionId()`
`ExecutionState`	`getExecutionState()`	Returns the current execution state of the task.
`Throwable`	`getFailureCause()`	If the task has failed, this method gets the exception that caused this task to fail.
`Configuration`	`getJobConfiguration()`
`JobID`	`getJobID()`
`JobVertexID`	`getJobVertexId()`
`TaskMetricGroup`	`getMetricGroup()`
`Configuration`	`getTaskConfiguration()`
`TaskInfo`	`getTaskInfo()`
`CompletableFuture<ExecutionState>`	`getTerminationFuture()`
`boolean`	`isBackPressured()`
`boolean`	`isCanceledOrFailed()`	Checks whether the task has failed, is canceled, or is being canceled at the moment.
`static void`	`logTaskThreadStackTrace(Thread thread, String taskName, long timeoutMs, String action)`
`void`	`notifyCheckpointAborted(long checkpointID, long latestCompletedCheckpointId)`
`void`	`notifyCheckpointComplete(long checkpointID)`
`void`	`notifyCheckpointSubsumed(long checkpointID)`
`void`	`requestPartitionProducerState(IntermediateDataSetID intermediateDataSetId, ResultPartitionID resultPartitionId, Consumer<? super PartitionProducerStateProvider.ResponseHandle> responseConsumer)`	Trigger the producer execution state request.
`void`	`run()`	The core work method that bootstraps the task and executes its code.
`static void`	`setupPartitionsAndGates(ResultPartitionWriter[] producedPartitions, InputGate[] inputGates)`
`void`	`startTaskThread()`	Starts the task's thread.
`String`	`toString()`
`void`	`triggerCheckpointBarrier(long checkpointID, long checkpointTimestamp, CheckpointOptions checkpointOptions)`	Calls the invokable to trigger a checkpoint.

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

Constructor Detail

Task

public Task(JobInformation jobInformation,
            TaskInformation taskInformation,
            ExecutionAttemptID executionAttemptID,
            AllocationID slotAllocationId,
            List<ResultPartitionDeploymentDescriptor> resultPartitionDeploymentDescriptors,
            List<InputGateDeploymentDescriptor> inputGateDeploymentDescriptors,
            MemoryManager memManager,
            SharedResources sharedResources,
            IOManager ioManager,
            ShuffleEnvironment<?,?> shuffleEnvironment,
            KvStateService kvStateService,
            BroadcastVariableManager bcVarManager,
            TaskEventDispatcher taskEventDispatcher,
            ExternalResourceInfoProvider externalResourceInfoProvider,
            TaskStateManager taskStateManager,
            TaskManagerActions taskManagerActions,
            InputSplitProvider inputSplitProvider,
            CheckpointResponder checkpointResponder,
            TaskOperatorEventGateway operatorCoordinatorEventGateway,
            GlobalAggregateManager aggregateManager,
            LibraryCacheManager.ClassLoaderHandle classLoaderHandle,
            FileCache fileCache,
            TaskManagerRuntimeInfo taskManagerConfig,
            @Nonnull
            TaskMetricGroup metricGroup,
            PartitionProducerStateChecker partitionProducerStateChecker,
            Executor executor,
            ChannelStateWriteRequestExecutorFactory channelStateExecutorFactory)

IMPORTANT: This constructor may not start any work that would need to be undone in the case of a failing task deployment.

Method Detail
- getJobID
```
public JobID getJobID()
```
  Specified by:
  
  getJobID in interface TaskSlotPayload
- getJobVertexId
```
public JobVertexID getJobVertexId()
```
- getExecutionId
```
public ExecutionAttemptID getExecutionId()
```
  Specified by:
  
  getExecutionId in interface TaskSlotPayload
- getAllocationId
```
public AllocationID getAllocationId()
```
  Specified by:
  
  getAllocationId in interface TaskSlotPayload
- getTaskInfo
```
public TaskInfo getTaskInfo()
```
- getJobConfiguration
```
public Configuration getJobConfiguration()
```
- getTaskConfiguration
```
public Configuration getTaskConfiguration()
```
- getAccumulatorRegistry
```
public AccumulatorRegistry getAccumulatorRegistry()
```
- getMetricGroup
```
public TaskMetricGroup getMetricGroup()
```
- getExecutingThread
```
public Thread getExecutingThread()
```
- getTerminationFuture
```
public CompletableFuture<ExecutionState> getTerminationFuture()
```
  Specified by:
  
  getTerminationFuture in interface TaskSlotPayload
- isBackPressured
```
public boolean isBackPressured()
```
- getExecutionState
```
public ExecutionState getExecutionState()
```
  Returns the current execution state of the task.
  
  Returns:
  
  The current execution state of the task.
- isCanceledOrFailed
```
public boolean isCanceledOrFailed()
```
  Checks whether the task has failed, is canceled, or is being canceled at the moment.
  
  Returns:
  
  True is the task in state FAILED, CANCELING, or CANCELED, false otherwise.
- getFailureCause
```
public Throwable getFailureCause()
```
  If the task has failed, this method gets the exception that caused this task to fail. Otherwise this method returns null.
  
  Returns:
  
  The exception that caused the task to fail, or null, if the task has not failed.
- startTaskThread
```
public void startTaskThread()
```
  Starts the task's thread.
- run
```
public void run()
```
  The core work method that bootstraps the task and executes its code.
  
  Specified by:
  
  run in interface Runnable
- setupPartitionsAndGates
```
@VisibleForTesting
public static void setupPartitionsAndGates(ResultPartitionWriter[] producedPartitions,
                                           InputGate[] inputGates)
                                    throws IOException
```
  Throws:
  
  IOException
- cancelExecution
```
public void cancelExecution()
```
  Cancels the task execution. If the task is already in a terminal state (such as FINISHED, CANCELED, FAILED), or if the task is already canceling this does nothing. Otherwise it sets the state to CANCELING, and, if the invokable code is running, starts an asynchronous thread that aborts that code.
  This method never blocks.
- failExternally
```
public void failExternally(Throwable cause)
```
  Marks task execution failed for an external reason (a reason other than the task code itself throwing an exception). If the task is already in a terminal state (such as FINISHED, CANCELED, FAILED), or if the task is already canceling this does nothing. Otherwise it sets the state to FAILED, and, if the invokable code is running, starts an asynchronous thread that aborts that code.
  This method never blocks.
  
  Specified by:
  
  failExternally in interface TaskActions
  
  Specified by:
  
  failExternally in interface TaskSlotPayload
  
  Parameters:
  
  cause - of the failure
- requestPartitionProducerState
```
public void requestPartitionProducerState(IntermediateDataSetID intermediateDataSetId,
                                          ResultPartitionID resultPartitionId,
                                          Consumer<? super PartitionProducerStateProvider.ResponseHandle> responseConsumer)
```
  Description copied from interface: PartitionProducerStateProvider
  
  Trigger the producer execution state request.
  
  Specified by:
  
  requestPartitionProducerState in interface PartitionProducerStateProvider
  
  Parameters:
  
  intermediateDataSetId - ID of the parent intermediate data set.
  
  resultPartitionId - ID of the result partition to check. This identifies the producing execution and partition.
  
  responseConsumer - consumer for the response handle.
- triggerCheckpointBarrier
```
public void triggerCheckpointBarrier(long checkpointID,
                                     long checkpointTimestamp,
                                     CheckpointOptions checkpointOptions)
```
  Calls the invokable to trigger a checkpoint.
  
  Parameters:
  
  checkpointID - The ID identifying the checkpoint.
  
  checkpointTimestamp - The timestamp associated with the checkpoint.
  
  checkpointOptions - Options for performing this checkpoint.
- notifyCheckpointComplete
```
public void notifyCheckpointComplete(long checkpointID)
```
- notifyCheckpointAborted
```
public void notifyCheckpointAborted(long checkpointID,
                                    long latestCompletedCheckpointId)
```
- notifyCheckpointSubsumed
```
public void notifyCheckpointSubsumed(long checkpointID)
```
- deliverOperatorEvent
```
public void deliverOperatorEvent(OperatorID operator,
                                 SerializedValue<OperatorEvent> evt)
                          throws FlinkException
```
  Dispatches an operator event to the invokable task.
  If the event delivery did not succeed, this method throws an exception. Callers can use that exception for error reporting, but need not react with failing this task (this method takes care of that).
  
  Throws:
  
  FlinkException - This method throws exceptions indicating the reason why delivery did not succeed.
- toString
```
public String toString()
```
  Overrides:
  
  toString in class Object
- logTaskThreadStackTrace
```
public static void logTaskThreadStackTrace(Thread thread,
                                           String taskName,
                                           long timeoutMs,
                                           String action)
```

Class Task

Nested Class Summary

Nested classes/interfaces inherited from interface org.apache.flink.runtime.io.network.partition.PartitionProducerStateProvider

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Constructor Detail

Task

Method Detail

getJobID

getJobVertexId

getExecutionId

getAllocationId

getTaskInfo

getJobConfiguration

getTaskConfiguration

getAccumulatorRegistry

getMetricGroup

getExecutingThread

getTerminationFuture

isBackPressured

getExecutionState

isCanceledOrFailed

getFailureCause

startTaskThread

run

setupPartitionsAndGates

cancelExecution

failExternally

requestPartitionProducerState

triggerCheckpointBarrier

notifyCheckpointComplete

notifyCheckpointAborted

notifyCheckpointSubsumed

deliverOperatorEvent

toString

logTaskThreadStackTrace