Pool

Bootstep managing the worker pool. Describes how to initialize the worker pool, and starts and stops the pool during worker start-up/shutdown.

Attributes

Attribute	Type	Description
requires	tuple = (Hub,)	A tuple containing the bootstep classes that must be initialized before this pool bootstep can start, specifically requiring the Hub.

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Constructor

Signature

def Pool(
    w: Any,
    autoscale: Union[str, list, None] = None,
    **kwargs: dict
)

Parameters

Name	Type	Description
w	Any	The worker instance being initialized.
autoscale	Union[str, list, None] = None	Optional autoscaling settings, either as a comma-separated string or a list of [max, min].
**kwargs	dict	Additional keyword arguments passed to the parent class constructor.

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Methods

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close()

@classmethod
def close(
    w: [Worker](../../events/state/worker.md?sid=celery_events_state_worker)
) - > null

Closes the worker pool gracefully, allowing existing tasks to complete before shutting down.

Parameters

Name	Type	Description
w	[Worker](../../events/state/worker.md?sid=celery_events_state_worker)	The worker instance containing the pool to be closed.

Returns

Type	Description
null	null

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terminate()

@classmethod
def terminate(
    w: [Worker](../../events/state/worker.md?sid=celery_events_state_worker)
) - > null

Terminates the worker pool immediately, forcing all active tasks to stop without waiting for completion.

Parameters

Name	Type	Description
w	[Worker](../../events/state/worker.md?sid=celery_events_state_worker)	The worker instance containing the pool to be terminated.

Returns

Type	Description
null	null

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create()

@classmethod
def create(
    w: [Worker](../../events/state/worker.md?sid=celery_events_state_worker)
) - > celery.concurrency.base.BasePool

Initializes and configures the worker pool instance based on the worker's concurrency settings and environment.

Parameters

Name	Type	Description
w	[Worker](../../events/state/worker.md?sid=celery_events_state_worker)	The worker instance for which the pool is being created and attached.

Returns

Type	Description
celery.concurrency.base.BasePool	The instantiated pool object configured for the current worker environment.

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info()

@classmethod
def info(
    w: [Worker](../../events/state/worker.md?sid=celery_events_state_worker)
) - > dict

Retrieves runtime information and statistics from the active worker pool.

Parameters

Name	Type	Description
w	[Worker](../../events/state/worker.md?sid=celery_events_state_worker)	The worker instance whose pool information is being queried.

Returns

Type	Description
dict	A dictionary containing the 'pool' key with status details or 'N/A' if no pool exists.

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register_with_event_loop()

@classmethod
def register_with_event_loop(
    w: [Worker](../../events/state/worker.md?sid=celery_events_state_worker),
    hub: kombu.asynchronous.Hub
) - > null

Integrates the worker pool with the asynchronous I/O hub to handle non-blocking operations.

Parameters

Name	Type	Description
w	[Worker](../../events/state/worker.md?sid=celery_events_state_worker)	The worker instance containing the pool to register.
hub	kombu.asynchronous.Hub	The event loop hub used for coordinating asynchronous I/O events.

Returns

Type	Description
null	null

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