org.apache.flink.runtime.jobgraph.tasks

Class AbstractInvokable

java.lang.Object

org.apache.flink.runtime.jobgraph.tasks.AbstractInvokable

All Implemented Interfaces:

CheckpointableTask, CoordinatedTask, TaskInvokable

Direct Known Subclasses:

BatchTask, DataSinkTask, DataSourceTask, IterationSynchronizationSinkTask

public abstract class AbstractInvokable
extends Object
implements TaskInvokable, CheckpointableTask, CoordinatedTask

A base implementation of TaskInvokable, CheckpointableTask, and CoordinatedTask with most methods throwing UnsupportedOperationException or doing nothing.

Any subclass that supports recoverable state and participates in checkpointing needs to override the methods of CheckpointableTask, such as triggerCheckpointAsync(CheckpointMetaData, CheckpointOptions), triggerCheckpointOnBarrier(CheckpointMetaData, CheckpointOptions, CheckpointMetricsBuilder), abortCheckpointOnBarrier(long, CheckpointException) and notifyCheckpointCompleteAsync(long).

Constructor Summary

Constructors

Constructor and Description
AbstractInvokable(Environment environment) Create an Invokable task and set its environment.

Method Summary

Modifier and Type	Method and Description
void	abortCheckpointOnBarrier(long checkpointId, CheckpointException cause) Aborts a checkpoint as the result of receiving possibly some checkpoint barriers, but at least one CancelCheckpointMarker.
void	cancel() This method is called when a task is canceled either as a result of a user abort or an execution failure.
void	cleanUp(Throwable throwable) Cleanup any resources used in TaskInvokable.invoke() OR TaskInvokable.restore().
void	dispatchOperatorEvent(OperatorID operator, org.apache.flink.util.SerializedValue<OperatorEvent> event)
int	getCurrentNumberOfSubtasks() Returns the current number of subtasks the respective task is split into.
Environment	getEnvironment() Returns the environment of this task.
org.apache.flink.api.common.ExecutionConfig	getExecutionConfig() Returns the global ExecutionConfig.
int	getIndexInSubtaskGroup() Returns the index of this subtask in the subtask group.
org.apache.flink.configuration.Configuration	getJobConfiguration() Returns the job configuration object which was attached to the original JobGraph.
org.apache.flink.configuration.Configuration	getTaskConfiguration() Returns the task configuration object which was attached to the original JobVertex.
ClassLoader	getUserCodeClassLoader() Returns the user code class loader of this invokable.
abstract void	invoke() Starts the execution.
boolean	isUsingNonBlockingInput()
void	maybeInterruptOnCancel(Thread toInterrupt, String taskName, Long timeout) Checks whether the task should be interrupted during cancellation and if so, execute the specified Runnable interruptAction.
Future<Void>	notifyCheckpointAbortAsync(long checkpointId, long latestCompletedCheckpointId) Invoked when a checkpoint has been aborted, i.e., when the checkpoint coordinator has received a decline message from one task and try to abort the targeted checkpoint by notification.
Future<Void>	notifyCheckpointCompleteAsync(long checkpointId) Invoked when a checkpoint has been completed, i.e., when the checkpoint coordinator has received the notification from all participating tasks.
Future<Void>	notifyCheckpointSubsumedAsync(long checkpointId) Invoked when a checkpoint has been subsumed, i.e., when the checkpoint coordinator has confirmed one checkpoint has been finished, and try to remove the first previous checkpoint.
void	restore() This method can be called before TaskInvokable.invoke() to restore an invokable object for the last valid state, if it has it.
CompletableFuture<Boolean>	triggerCheckpointAsync(CheckpointMetaData checkpointMetaData, CheckpointOptions checkpointOptions) This method is called to trigger a checkpoint, asynchronously by the checkpoint coordinator.
void	triggerCheckpointOnBarrier(CheckpointMetaData checkpointMetaData, CheckpointOptions checkpointOptions, CheckpointMetricsBuilder checkpointMetrics) This method is called when a checkpoint is triggered as a result of receiving checkpoint barriers on all input streams.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

AbstractInvokable

public AbstractInvokable(Environment environment)

Create an Invokable task and set its environment.

Parameters:

environment - The environment assigned to this invokable.

Method Detail

invoke

public abstract void invoke()
                     throws Exception

Description copied from interface: TaskInvokable

Starts the execution.

This method is called by the task manager when the actual execution of the task starts.

All resources should be cleaned up by calling TaskInvokable.cleanUp(Throwable) after the method returns.

Specified by:

invoke in interface TaskInvokable

Throws:

Exception

cancel

public void cancel()
            throws Exception

Description copied from interface: TaskInvokable

This method is called when a task is canceled either as a result of a user abort or an execution failure. It can be overwritten to respond to shut down the user code properly.

Specified by:

cancel in interface TaskInvokable

Throws:

Exception

cleanUp

public void cleanUp(@Nullable
                    Throwable throwable)
             throws Exception

Description copied from interface: TaskInvokable

Cleanup any resources used in TaskInvokable.invoke() OR TaskInvokable.restore(). This method must be called regardless whether the aforementioned calls succeeded or failed.

Specified by:

cleanUp in interface TaskInvokable

Parameters:

throwable - iff failure happened during the execution of TaskInvokable.restore() or TaskInvokable.invoke(), null otherwise.

ATTENTION: CancelTaskException should not be treated as a failure.

Throws:

Exception

maybeInterruptOnCancel

public void maybeInterruptOnCancel(Thread toInterrupt,
                                   @Nullable
                                   String taskName,
                                   @Nullable
                                   Long timeout)

Description copied from interface: TaskInvokable

Checks whether the task should be interrupted during cancellation and if so, execute the specified Runnable interruptAction.

Specified by:

maybeInterruptOnCancel in interface TaskInvokable

taskName - optional taskName to log stack trace

timeout - optional timeout to log stack trace

getEnvironment

public final Environment getEnvironment()

Returns the environment of this task.

Returns:

The environment of this task.

getUserCodeClassLoader

public final ClassLoader getUserCodeClassLoader()

Returns the user code class loader of this invokable.

Returns:

user code class loader of this invokable.

getCurrentNumberOfSubtasks

public int getCurrentNumberOfSubtasks()

Returns the current number of subtasks the respective task is split into.

Returns:

the current number of subtasks the respective task is split into

getIndexInSubtaskGroup

public int getIndexInSubtaskGroup()

Returns the index of this subtask in the subtask group.

Returns:

the index of this subtask in the subtask group

getTaskConfiguration

public final org.apache.flink.configuration.Configuration getTaskConfiguration()

Returns the task configuration object which was attached to the original JobVertex.

Returns:

the task configuration object which was attached to the original JobVertex

getJobConfiguration

public org.apache.flink.configuration.Configuration getJobConfiguration()

Returns the job configuration object which was attached to the original JobGraph.

Returns:

the job configuration object which was attached to the original JobGraph

getExecutionConfig

public org.apache.flink.api.common.ExecutionConfig getExecutionConfig()

Returns the global ExecutionConfig.

triggerCheckpointAsync

public CompletableFuture<Boolean> triggerCheckpointAsync(CheckpointMetaData checkpointMetaData,
                                                         CheckpointOptions checkpointOptions)

Description copied from interface: CheckpointableTask

This method is called to trigger a checkpoint, asynchronously by the checkpoint coordinator.

This method is called for tasks that start the checkpoints by injecting the initial barriers, i.e., the source tasks. In contrast, checkpoints on downstream operators, which are the result of receiving checkpoint barriers, invoke the CheckpointableTask.triggerCheckpointOnBarrier(CheckpointMetaData, CheckpointOptions, CheckpointMetricsBuilder) method.

Specified by:

triggerCheckpointAsync in interface CheckpointableTask

Parameters:

checkpointMetaData - Meta data for about this checkpoint

checkpointOptions - Options for performing this checkpoint

Returns:

future with value of false if the checkpoint was not carried out, true otherwise

triggerCheckpointOnBarrier

public void triggerCheckpointOnBarrier(CheckpointMetaData checkpointMetaData,
                                       CheckpointOptions checkpointOptions,
                                       CheckpointMetricsBuilder checkpointMetrics)
                                throws IOException

Description copied from interface: CheckpointableTask

This method is called when a checkpoint is triggered as a result of receiving checkpoint barriers on all input streams.

Specified by:

triggerCheckpointOnBarrier in interface CheckpointableTask

Parameters:

checkpointMetaData - Meta data for about this checkpoint

checkpointOptions - Options for performing this checkpoint

checkpointMetrics - Metrics about this checkpoint

Throws:

IOException - Exceptions thrown as the result of triggering a checkpoint are forwarded.

abortCheckpointOnBarrier

public void abortCheckpointOnBarrier(long checkpointId,
                                     CheckpointException cause)
                              throws IOException

Description copied from interface: CheckpointableTask

Aborts a checkpoint as the result of receiving possibly some checkpoint barriers, but at least one CancelCheckpointMarker.

This requires implementing tasks to forward a CancelCheckpointMarker to their outputs.

Specified by:

abortCheckpointOnBarrier in interface CheckpointableTask

Parameters:

checkpointId - The ID of the checkpoint to be aborted.

cause - The reason why the checkpoint was aborted during alignment

Throws:

IOException

notifyCheckpointCompleteAsync

public Future<Void> notifyCheckpointCompleteAsync(long checkpointId)

Description copied from interface: CheckpointableTask

Invoked when a checkpoint has been completed, i.e., when the checkpoint coordinator has received the notification from all participating tasks.

Specified by:

notifyCheckpointCompleteAsync in interface CheckpointableTask

Parameters:

checkpointId - The ID of the checkpoint that is complete.

Returns:

future that completes when the notification has been processed by the task.

notifyCheckpointAbortAsync

public Future<Void> notifyCheckpointAbortAsync(long checkpointId,
                                               long latestCompletedCheckpointId)

Description copied from interface: CheckpointableTask

Invoked when a checkpoint has been aborted, i.e., when the checkpoint coordinator has received a decline message from one task and try to abort the targeted checkpoint by notification.

Specified by:

notifyCheckpointAbortAsync in interface CheckpointableTask

Parameters:

checkpointId - The ID of the checkpoint that is aborted.

latestCompletedCheckpointId - The ID of the latest completed checkpoint.

Returns:

future that completes when the notification has been processed by the task.

notifyCheckpointSubsumedAsync

public Future<Void> notifyCheckpointSubsumedAsync(long checkpointId)

Description copied from interface: CheckpointableTask

Invoked when a checkpoint has been subsumed, i.e., when the checkpoint coordinator has confirmed one checkpoint has been finished, and try to remove the first previous checkpoint.

Specified by:

notifyCheckpointSubsumedAsync in interface CheckpointableTask

Parameters:

checkpointId - The ID of the checkpoint that is subsumed.

Returns:

future that completes when the notification has been processed by the task.

dispatchOperatorEvent

public void dispatchOperatorEvent(OperatorID operator,
                                  org.apache.flink.util.SerializedValue<OperatorEvent> event)
                           throws org.apache.flink.util.FlinkException

Specified by:

dispatchOperatorEvent in interface CoordinatedTask

Throws:

org.apache.flink.util.FlinkException

restore

public void restore()
             throws Exception

Description copied from interface: TaskInvokable

This method can be called before TaskInvokable.invoke() to restore an invokable object for the last valid state, if it has it.

If TaskInvokable.invoke() is not called after this method for some reason (e.g. task cancellation); then all resources should be cleaned up by calling TaskInvokable.cleanUp(Throwable) ()} after the method returns.

Specified by:

restore in interface TaskInvokable

Throws:

Exception

isUsingNonBlockingInput

public boolean isUsingNonBlockingInput()

Specified by:

isUsingNonBlockingInput in interface TaskInvokable

Returns:

true if blocking input such as InputGate.getNext() is used (as opposed to InputGate.pollNext(). To be removed together with the DataSet API.