CompoundTask Class

A Task of Tasks.

Contains shared logic that drives all of its sub-classes. Should never be instantiated on its own.

Instantiate CompoundTask attributes.

Constructor

CompoundTask(tasks: List[TaskBase], compound_action_constructor=None)

Parameters

Name	Description
tasks Required	<xref:List>[<xref:Task>] The children/sub-tasks of this Task
compound_action_constructor	<xref:Union>[<xref:WhenAllAction>, <xref:azure.durable_functions.models.Task.WhenAnyAction>, None] Either None or, a WhenAllAction or WhenAnyAction constructor. It is None when using the V1 replay protocol, where no Compound Action objects size and compound actions are represented as arrays of actions. It is not None when using the V2 replay protocol. Default value: None

Methods

change_state	Transition a running Task to a terminal state: success or failure.
handle_completion	Manage sub-task completion events.
propagate	Notify parent Task of this Task's state change.
set_is_played	Set the is_played flag for the Task. Needed for updating the orchestrator's is_replaying flag.
set_value	Set the value of this Task: either an exception of a result.
try_set_value	Transition a CompoundTask to a terminal state and set its value. Should be implemented by sub-classes.

change_state

Transition a running Task to a terminal state: success or failure.

change_state(state: TaskState)

Parameters

Name	Description
state Required	TaskState The terminal state to assign to this Task

Exceptions

Type	Description
Exception	When the input state is RUNNING

handle_completion

Manage sub-task completion events.

handle_completion(child: TaskBase)

Parameters

Name	Description
child Required	TaskBase The sub-task that completed

Exceptions

Type	Description
Exception	When the calling sub-task was not registered with this Task's pending sub-tasks.

propagate

Notify parent Task of this Task's state change.

propagate()

set_is_played

Set the is_played flag for the Task.

Needed for updating the orchestrator's is_replaying flag.

set_is_played(is_played: bool)

Parameters

Name	Description
is_played Required	bool Whether the latest event for this Task has been played before.

set_value

Set the value of this Task: either an exception of a result.

set_value(is_error: bool, value: Any)

Parameters

Name	Description
is_error Required	bool Whether the value represents an exception of a result.
value Required	Any The value of this Task

Exceptions

Type	Description
Exception	When the Task failed but its value was not an Exception

try_set_value

Transition a CompoundTask to a terminal state and set its value.

Should be implemented by sub-classes.

try_set_value(child: TaskBase)

Parameters

Name	Description
child Required	TaskBase A sub-task that just completed

Exceptions

Type	Description
NotImplementedError	This method needs to be implemented by each subclass.

Attributes

is_completed

Get indicator of whether the task completed.

Note that completion is not equivalent to success.