TaskPool

This class implements a thread-based task pool using a thread pool executor to manage concurrent execution. It provides mechanisms to submit tasks with optional callbacks and ensures proper resource cleanup by shutting down the executor when the pool is stopped. The class also tracks pool-specific metadata such as maximum concurrency and the current number of active threads.

Attributes

Attribute	Type	Description
limit	int	The maximum number of concurrent worker threads allowed in the pool.
body_can_be_buffer	boolean = True	Indicates whether the task payload can be processed as a buffer object.
signal_safe	boolean = False	Flag indicating if the pool implementation can safely handle POSIX signals.

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Constructor

Signature

def TaskPool(
    *args: Any,
    **kwargs: Any
) - > None

Parameters

Name	Type	Description
*args	Any	Variable length argument list passed to the base class constructor.
**kwargs	Any	Arbitrary keyword arguments passed to the base class constructor.

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Methods

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on_stop()

@classmethod
def on_stop() - > None

Shuts down the underlying thread pool executor and cancels any pending futures before calling the base stop logic.

Returns

Type	Description
None	Nothing

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on_apply()

@classmethod
def on_apply(
    target: TargetFunction,
    args: tuple[Any, ...]| None,
    kwargs: dict[str, Any]| None,
    callback: Callable[..., Any]| None,
    accept_callback: Callable[..., Any]| None
) - > [ApplyResult](applyresult.md?sid=celery_concurrency_thread_applyresult)

Submits a target function for execution within the thread pool and returns an object to track the result.

Parameters

Name	Type	Description
target	TargetFunction	The callable function or task to be executed by a worker thread
args	`tuple[Any, ...]	None`
kwargs	`dict[str, Any]	None`
callback	`Callable[..., Any]	None`
accept_callback	`Callable[..., Any]	None`

Returns

Type	Description
[ApplyResult](applyresult.md?sid=celery_concurrency_thread_applyresult)	A handle used to track the execution status and retrieve the result of the submitted task

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