org.apache.flink.streaming.runtime.tasks

类 StreamTask<OUT,OP extends StreamOperator<OUT>>

java.lang.Object

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

org.apache.flink.streaming.runtime.tasks.StreamTask<OUT,OP>

类型参数:

OUT -

OP -

所有已实现的接口:

AsyncExceptionHandler

直接已知子类:

AbstractTwoInputStreamTask, OneInputStreamTask, SourceReaderStreamTask, SourceStreamTask

@Internal
public abstract class StreamTask<OUT,OP extends StreamOperator<OUT>>
extends org.apache.flink.runtime.jobgraph.tasks.AbstractInvokable
implements AsyncExceptionHandler

Base class for all streaming tasks. A task is the unit of local processing that is deployed and executed by the TaskManagers. Each task runs one or more StreamOperators which form the Task's operator chain. Operators that are chained together execute synchronously in the same thread and hence on the same stream partition. A common case for these chains are successive map/flatmap/filter tasks.

The task chain contains one "head" operator and multiple chained operators. The StreamTask is specialized for the type of the head operator: one-input and two-input tasks, as well as for sources, iteration heads and iteration tails.

The Task class deals with the setup of the streams read by the head operator, and the streams produced by the operators at the ends of the operator chain. Note that the chain may fork and thus have multiple ends.

The life cycle of the task is set up as follows:

  -- setInitialState -> provides state of all operators in the chain

  -- invoke()
        |
        +----> Create basic utils (config, etc) and load the chain of operators
        +----> operators.setup()
        +----> task specific init()
        +----> initialize-operator-states()
        +----> open-operators()
        +----> run()
        +----> close-operators()
        +----> dispose-operators()
        +----> common cleanup
        +----> task specific cleanup()
 

The StreamTask has a lock object called lock. All calls to methods on a StreamOperator must be synchronized on this lock object to ensure that no methods are called concurrently.

嵌套类概要

嵌套类

限定符和类型	类和说明
protected static class	StreamTask.AsyncCheckpointRunnable This runnable executes the asynchronous parts of all involved backend snapshots for the subtask.

字段概要

字段

限定符和类型	字段和说明
protected StreamConfig	configuration The configuration of this streaming task.
protected OP	headOperator the head operator that consumes the input streams of this task.
protected StreamInputProcessor	inputProcessor The input processor.
protected static org.slf4j.Logger	LOG The logger used by the StreamTask and its subclasses.
protected MailboxProcessor	mailboxProcessor
protected OperatorChain<OUT,OP>	operatorChain The chain of operators executed by this task.
protected org.apache.flink.runtime.state.StateBackend	stateBackend Our state backend.
protected TimerService	timerService The internal TimerService used to define the current processing time (default = System.currentTimeMillis()) and register timers for tasks to be executed in the future.
static ThreadGroup	TRIGGER_THREAD_GROUP The thread group that holds all trigger timer threads.

构造器概要

构造器

限定符	构造器和说明
protected	StreamTask(org.apache.flink.runtime.execution.Environment env) Constructor for initialization, possibly with initial state (recovery / savepoint / etc).
protected	StreamTask(org.apache.flink.runtime.execution.Environment env, TimerService timerService) Constructor for initialization, possibly with initial state (recovery / savepoint / etc).
protected	StreamTask(org.apache.flink.runtime.execution.Environment environment, TimerService timerService, Thread.UncaughtExceptionHandler uncaughtExceptionHandler)
protected	StreamTask(org.apache.flink.runtime.execution.Environment environment, TimerService timerService, Thread.UncaughtExceptionHandler uncaughtExceptionHandler, StreamTaskActionExecutor.SynchronizedStreamTaskActionExecutor actionExecutor) Constructor for initialization, possibly with initial state (recovery / savepoint / etc).
protected	StreamTask(org.apache.flink.runtime.execution.Environment environment, TimerService timerService, Thread.UncaughtExceptionHandler uncaughtExceptionHandler, StreamTaskActionExecutor.SynchronizedStreamTaskActionExecutor actionExecutor, TaskMailbox mailbox)

方法概要

限定符和类型	方法和说明
void	abortCheckpointOnBarrier(long checkpointId, Throwable cause)
protected void	advanceToEndOfEventTime() Emits the MAX_WATERMARK so that all registered timers are fired.
void	cancel()
protected void	cancelTask()
protected void	cleanup()
static <OUT> org.apache.flink.runtime.io.network.api.writer.RecordWriterDelegate<org.apache.flink.runtime.plugable.SerializationDelegate<StreamRecord<OUT>>>	createRecordWriterDelegate(StreamConfig configuration, org.apache.flink.runtime.execution.Environment environment)
StreamTaskStateInitializer	createStreamTaskStateInitializer()
protected void	declineCheckpoint(long checkpointId)
protected void	finalize() The finalize method shuts down the timer.
protected void	finishTask() Instructs the task to go through its normal termination routine, i.e. exit the run-loop and call StreamOperator.close() and StreamOperator.dispose() on its operators.
Map<String,org.apache.flink.api.common.accumulators.Accumulator<?,?>>	getAccumulatorMap()
ExecutorService	getAsyncOperationsThreadPool()
org.apache.flink.core.fs.CloseableRegistry	getCancelables()
Object	getCheckpointLock() 已过时。 This method will be removed in future releases. Use mailbox executor to run StreamTask actions that require synchronization (e.g. checkpointing, collecting output). For other (non-StreamTask) actions other synchronization means can be used. MailboxExecutor yield or tryYield methods can be used for actions that should give control to other actions temporarily. MailboxExecutor can be accessed by using YieldingOperatorFactory. Example usage can be found in AsyncWaitOperator.
org.apache.flink.runtime.state.CheckpointStorageWorkerView	getCheckpointStorage()
StreamConfig	getConfiguration()
MailboxExecutorFactory	getMailboxExecutorFactory()
String	getName() Gets the name of the task, in the form "taskname (2/5)".
ProcessingTimeService	getProcessingTimeService(int operatorIndex)
StreamStatusMaintainer	getStreamStatusMaintainer()
void	handleAsyncException(String message, Throwable exception) Handles an exception thrown by another thread (e.g. a TriggerTask), other than the one executing the main task by failing the task entirely.
protected void	handleCheckpointException(Exception exception)
protected abstract void	init()
void	invoke()
boolean	isCanceled()
boolean	isRunning()
Future<Void>	notifyCheckpointCompleteAsync(long checkpointId)
protected void	processInput(MailboxDefaultAction.Controller controller) This method implements the default action of the task (e.g. processing one event from the input).
protected org.apache.flink.metrics.Counter	setupNumRecordsInCounter(StreamOperator streamOperator)
String	toString()
Future<Boolean>	triggerCheckpointAsync(org.apache.flink.runtime.checkpoint.CheckpointMetaData checkpointMetaData, org.apache.flink.runtime.checkpoint.CheckpointOptions checkpointOptions, boolean advanceToEndOfEventTime)
void	triggerCheckpointOnBarrier(org.apache.flink.runtime.checkpoint.CheckpointMetaData checkpointMetaData, org.apache.flink.runtime.checkpoint.CheckpointOptions checkpointOptions, org.apache.flink.runtime.checkpoint.CheckpointMetrics checkpointMetrics)

从类继承的方法 org.apache.flink.runtime.jobgraph.tasks.AbstractInvokable

getCurrentNumberOfSubtasks, getEnvironment, getExecutionConfig, getIndexInSubtaskGroup, getJobConfiguration, getTaskConfiguration, getUserCodeClassLoader, setShouldInterruptOnCancel, shouldInterruptOnCancel

从类继承的方法 java.lang.Object

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

字段详细资料

TRIGGER_THREAD_GROUP

public static final ThreadGroup TRIGGER_THREAD_GROUP

The thread group that holds all trigger timer threads.

LOG

protected static final org.slf4j.Logger LOG

The logger used by the StreamTask and its subclasses.

inputProcessor

@Nullable
protected StreamInputProcessor inputProcessor

The input processor. Initialized in init() method.

headOperator

protected OP extends StreamOperator<OUT> headOperator

the head operator that consumes the input streams of this task.

operatorChain

protected OperatorChain<OUT,OP extends StreamOperator<OUT>> operatorChain

The chain of operators executed by this task.

configuration

protected final StreamConfig configuration

The configuration of this streaming task.

stateBackend

protected org.apache.flink.runtime.state.StateBackend stateBackend

Our state backend. We use this to create checkpoint streams and a keyed state backend.

timerService

protected TimerService timerService

The internal TimerService used to define the current processing time (default = System.currentTimeMillis()) and register timers for tasks to be executed in the future.

mailboxProcessor

protected final MailboxProcessor mailboxProcessor

构造器详细资料

StreamTask

protected StreamTask(org.apache.flink.runtime.execution.Environment env)

Constructor for initialization, possibly with initial state (recovery / savepoint / etc).

参数:

env - The task environment for this task.

StreamTask

protected StreamTask(org.apache.flink.runtime.execution.Environment env,
                     @Nullable
                     TimerService timerService)

Constructor for initialization, possibly with initial state (recovery / savepoint / etc).

参数:

env - The task environment for this task.

timerService - Optionally, a specific timer service to use.

StreamTask

protected StreamTask(org.apache.flink.runtime.execution.Environment environment,
                     @Nullable
                     TimerService timerService,
                     Thread.UncaughtExceptionHandler uncaughtExceptionHandler)

StreamTask

protected StreamTask(org.apache.flink.runtime.execution.Environment environment,
                     @Nullable
                     TimerService timerService,
                     Thread.UncaughtExceptionHandler uncaughtExceptionHandler,
                     StreamTaskActionExecutor.SynchronizedStreamTaskActionExecutor actionExecutor)

Constructor for initialization, possibly with initial state (recovery / savepoint / etc).

This constructor accepts a special TimerService. By default (and if null is passes for the timer service) a DefaultTimerService will be used.

参数:

environment - The task environment for this task.

timerService - Optionally, a specific timer service to use.

uncaughtExceptionHandler - to handle uncaught exceptions in the async operations thread pool

actionExecutor - a mean to wrap all actions performed by this task thread. Currently, only SynchronizedActionExecutor can be used to preserve locking semantics.

StreamTask

protected StreamTask(org.apache.flink.runtime.execution.Environment environment,
                     @Nullable
                     TimerService timerService,
                     Thread.UncaughtExceptionHandler uncaughtExceptionHandler,
                     StreamTaskActionExecutor.SynchronizedStreamTaskActionExecutor actionExecutor,
                     TaskMailbox mailbox)

方法详细资料

init

protected abstract void init()
                      throws Exception

抛出:

Exception

cancelTask

protected void cancelTask()
                   throws Exception

抛出:

Exception

cleanup

protected void cleanup()
                throws Exception

抛出:

Exception

processInput

protected void processInput(MailboxDefaultAction.Controller controller)
                     throws Exception

This method implements the default action of the task (e.g. processing one event from the input). Implementations should (in general) be non-blocking.

参数:

controller - controller object for collaborative interaction between the action and the stream task.

抛出:

Exception - on any problems in the action.

advanceToEndOfEventTime

protected void advanceToEndOfEventTime()
                                throws Exception

Emits the MAX_WATERMARK so that all registered timers are fired.

This is used by the source task when the job is TERMINATED. In the case, we want all the timers registered throughout the pipeline to fire and the related state (e.g. windows) to be flushed.

For tasks other than the source task, this method does nothing.

抛出:

Exception

finishTask

protected void finishTask()
                   throws Exception

Instructs the task to go through its normal termination routine, i.e. exit the run-loop and call StreamOperator.close() and StreamOperator.dispose() on its operators.

This is used by the source task to get out of the run-loop when the job is stopped with a savepoint.

For tasks other than the source task, this method does nothing.

抛出:

Exception

createStreamTaskStateInitializer

public StreamTaskStateInitializer createStreamTaskStateInitializer()

setupNumRecordsInCounter

protected org.apache.flink.metrics.Counter setupNumRecordsInCounter(StreamOperator streamOperator)

invoke

public final void invoke()
                  throws Exception

指定者:

invoke 在类中 org.apache.flink.runtime.jobgraph.tasks.AbstractInvokable

抛出:

Exception

cancel

public final void cancel()
                  throws Exception

覆盖:

cancel 在类中 org.apache.flink.runtime.jobgraph.tasks.AbstractInvokable

抛出:

Exception

getMailboxExecutorFactory

public MailboxExecutorFactory getMailboxExecutorFactory()

isRunning

public final boolean isRunning()

isCanceled

public final boolean isCanceled()

finalize

protected void finalize()
                 throws Throwable

The finalize method shuts down the timer. This is a fail-safe shutdown, in case the original shutdown method was never called.

This should not be relied upon! It will cause shutdown to happen much later than if manual shutdown is attempted, and cause threads to linger for longer than needed.

覆盖:

finalize 在类中 Object

抛出:

Throwable

getName

public String getName()

Gets the name of the task, in the form "taskname (2/5)".

返回:

The name of the task.

getCheckpointLock

@Deprecated
public Object getCheckpointLock()

已过时。 This method will be removed in future releases. Use mailbox executor to run StreamTask actions that require synchronization (e.g. checkpointing, collecting output).

For other (non-StreamTask) actions other synchronization means can be used.

MailboxExecutor yield or tryYield methods can be used for actions that should give control to other actions temporarily.

MailboxExecutor can be accessed by using YieldingOperatorFactory. Example usage can be found in AsyncWaitOperator.

Gets the lock object on which all operations that involve data and state mutation have to lock.

返回:

The checkpoint lock object.

getCheckpointStorage

public org.apache.flink.runtime.state.CheckpointStorageWorkerView getCheckpointStorage()

getConfiguration

public StreamConfig getConfiguration()

getAccumulatorMap

public Map<String,org.apache.flink.api.common.accumulators.Accumulator<?,?>> getAccumulatorMap()

getStreamStatusMaintainer

public StreamStatusMaintainer getStreamStatusMaintainer()

triggerCheckpointAsync

public Future<Boolean> triggerCheckpointAsync(org.apache.flink.runtime.checkpoint.CheckpointMetaData checkpointMetaData,
                                              org.apache.flink.runtime.checkpoint.CheckpointOptions checkpointOptions,
                                              boolean advanceToEndOfEventTime)

覆盖:

triggerCheckpointAsync 在类中 org.apache.flink.runtime.jobgraph.tasks.AbstractInvokable

triggerCheckpointOnBarrier

public void triggerCheckpointOnBarrier(org.apache.flink.runtime.checkpoint.CheckpointMetaData checkpointMetaData,
                                       org.apache.flink.runtime.checkpoint.CheckpointOptions checkpointOptions,
                                       org.apache.flink.runtime.checkpoint.CheckpointMetrics checkpointMetrics)
                                throws Exception

覆盖:

triggerCheckpointOnBarrier 在类中 org.apache.flink.runtime.jobgraph.tasks.AbstractInvokable

抛出:

Exception

abortCheckpointOnBarrier

public void abortCheckpointOnBarrier(long checkpointId,
                                     Throwable cause)
                              throws Exception

覆盖:

abortCheckpointOnBarrier 在类中 org.apache.flink.runtime.jobgraph.tasks.AbstractInvokable

抛出:

Exception

declineCheckpoint

protected void declineCheckpoint(long checkpointId)

handleCheckpointException

protected void handleCheckpointException(Exception exception)

getAsyncOperationsThreadPool

public ExecutorService getAsyncOperationsThreadPool()

notifyCheckpointCompleteAsync

public Future<Void> notifyCheckpointCompleteAsync(long checkpointId)

覆盖:

notifyCheckpointCompleteAsync 在类中 org.apache.flink.runtime.jobgraph.tasks.AbstractInvokable

getProcessingTimeService

public ProcessingTimeService getProcessingTimeService(int operatorIndex)

handleAsyncException

public void handleAsyncException(String message,
                                 Throwable exception)

Handles an exception thrown by another thread (e.g. a TriggerTask), other than the one executing the main task by failing the task entirely.

In more detail, it 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.

指定者:

handleAsyncException 在接口中 AsyncExceptionHandler

toString

public String toString()

覆盖:

toString 在类中 Object

getCancelables

public org.apache.flink.core.fs.CloseableRegistry getCancelables()

createRecordWriterDelegate

@VisibleForTesting
public static <OUT> org.apache.flink.runtime.io.network.api.writer.RecordWriterDelegate<org.apache.flink.runtime.plugable.SerializationDelegate<StreamRecord<OUT>>> createRecordWriterDelegate(StreamConfig configuration,
                                                                                                                                                                                                                  org.apache.flink.runtime.execution.Environment environment)