BaseLoader

Base class for loaders.

Loaders handles,

* Reading celery client/worker configurations.

* What happens when a task starts?
    See :meth:`on_task_init`.

* What happens when the worker starts?
    See :meth:`on_worker_init`.

* What happens when the worker shuts down?
    See :meth:`on_worker_shutdown`.

* What modules are imported to find tasks?

Attributes

Attribute	Type	Description
builtin_modules	frozenset = frozenset()	A set of module names that are automatically imported by the loader to find tasks.
configured	boolean = false	A boolean flag indicating whether the loader has successfully read and applied its configuration.
override_backends	dict = {}	A mapping used to specify alternative result backend classes that override the default configuration.
worker_initialized	boolean = false	A boolean flag that tracks if the worker-specific initialization process has been completed.

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Constructor

Signature

def BaseLoader(
    app: Any,
    **kwargs: dict
)

Parameters

Name	Type	Description
app	Any	The Celery application instance associated with this loader.
**kwargs	dict	Additional keyword arguments.

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Methods

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now()

@classmethod
def now(
    utc: boolean = True
) - > datetime

Returns the current date and time, optionally in UTC format.

Parameters

Name	Type	Description
utc	boolean = True	Determines whether to return the time in UTC or local time

Returns

Type	Description
datetime	The current timestamp as a datetime object

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on_task_init()

@classmethod
def on_task_init(
    task_id: string,
    task: [Task](../../events/state/task.md?sid=celery_events_state_task)
)

Called before a task is executed.

Parameters

Name	Type	Description
task_id	string	The unique identifier of the task being initialized
task	[Task](../../events/state/task.md?sid=celery_events_state_task)	The task instance that is about to be executed

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on_process_cleanup()

@classmethod
def on_process_cleanup()

Called after a task is executed.

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on_worker_init()

@classmethod
def on_worker_init()

Called when the worker (:program:celery worker) starts.

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on_worker_shutdown()

@classmethod
def on_worker_shutdown()

Called when the worker (:program:celery worker) shuts down.

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on_worker_process_init()

@classmethod
def on_worker_process_init()

Called when a child process starts.

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import_task_module()

@classmethod
def import_task_module(
    module: string
) - > module

Imports a specific task module and tracks it within the loader's task module set.

Parameters

Name	Type	Description
module	string	The name of the module to import

Returns

Type	Description
module	The imported module object

---

import_module()

@classmethod
def import_module(
    module: string,
    package: string = null
) - > module

Imports a module by name using the standard importlib mechanism.

Parameters

Name	Type	Description
module	string	The name of the module to import
package	string = null	The package name to use for relative imports

Returns

Type	Description
module	The imported module object

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import_from_cwd()

@classmethod
def import_from_cwd(
    module: string,
    imp: callable = null,
    package: string = null
) - > module

Imports a module while ensuring the current working directory is included in the search path.

Parameters

Name	Type	Description
module	string	The name of the module to import
imp	callable = null	The underlying import function to use; defaults to self.import_module
package	string = null	The package name for relative imports

Returns

Type	Description
module	The imported module object

---

import_default_modules()

@classmethod
def import_default_modules() - > list

Imports all modules defined in the default_modules property and triggers the import_modules signal.

Returns

Type	Description
list	A list of the imported module objects

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init_worker()

@classmethod
def init_worker()

Initializes the worker state by importing default modules and triggering the worker initialization hook.

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shutdown_worker()

@classmethod
def shutdown_worker()

Triggers the worker shutdown hook to perform cleanup tasks.

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init_worker_process()

@classmethod
def init_worker_process()

Triggers the child process initialization hook.

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config_from_object()

@classmethod
def config_from_object(
    obj: object|string,
    silent: boolean = False
) - > boolean

Loads configuration values from a given object, dictionary, or module path.

Parameters

Name	Type	Description
obj	`object	string`
silent	boolean = False	If True, suppresses ImportErrors when the object is a string path

Returns

Type	Description
boolean	True if the configuration was successfully loaded

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find_module()

@classmethod
def find_module(
    module: string
) - > object

Locates a module within the filesystem or python path.

Parameters

Name	Type	Description
module	string	The name of the module to find

Returns

Type	Description
object	The module location information

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cmdline_config_parser()

@classmethod
def cmdline_config_parser(
    args: list,
    namespace: string = 'celery',
    re_type: regex = re.compile(r'\((\w+)\)'),
    extra_types: dict = null,
    override_types: dict = null
) - > dict

Parses command-line configuration arguments into a dictionary of settings.

Parameters

Name	Type	Description
args	list	A list of 'key=value' strings from the command line
namespace	string = 'celery'	The default prefix for configuration keys
re_type	regex = re.compile(r'((\w+))')	Regex used to detect type casting hints in values
extra_types	dict = null	Additional type mapping functions for custom casting
override_types	dict = null	Mappings to override default type behaviors

Returns

Type	Description
dict	A dictionary of parsed configuration keys and their cast values

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read_configuration()

@classmethod
def read_configuration(
    env: string = 'CELERY_CONFIG_MODULE'
) - > DictAttribute|null

Reads the configuration module specified in the environment variables.

Parameters

Name	Type	Description
env	string = 'CELERY_CONFIG_MODULE'	The environment variable name that holds the config module path

Returns

Type	Description
`DictAttribute	null`

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autodiscover_tasks()

@classmethod
def autodiscover_tasks(
    packages: list,
    related_name: string = 'tasks'
)

Searches for task modules within specified packages and adds them to the internal registry.

Parameters

Name	Type	Description
packages	list	A list of package names to search for tasks
related_name	string = 'tasks'	The name of the module to look for within each package

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default_modules()

@classmethod
def default_modules() - > tuple

Fetches the list of modules to be imported by default, including built-ins and app-configured imports.

Returns

Type	Description
tuple	A tuple of module names to import

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conf()

@classmethod
def conf() - > dict

Loader configuration.

Returns

Type	Description
dict	The current configuration mapping

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