This document describes the current stable version of Celery (5.2). For development docs, go here.

celery.utils.objects

Object related utilities, including introspection, etc.

class celery.utils.objects.Bunch(**kwargs)

Object that enables you to modify attributes.

class celery.utils.objects.FallbackContext(provided, fallback, *fb_args, **fb_kwargs)

Context workaround.

The built-in @contextmanager utility does not work well when wrapping other contexts, as the traceback is wrong when the wrapped context raises.

This solves this problem and can be used instead of @contextmanager in this example:

@contextmanager
def connection_or_default_connection(connection=None):
    if connection:
        # user already has a connection, shouldn't close
        # after use
        yield connection
    else:
        # must've new connection, and also close the connection
        # after the block returns
        with create_new_connection() as connection:
            yield connection

This wrapper can be used instead for the above like this:

def connection_or_default_connection(connection=None):
    return FallbackContext(connection, create_new_connection)

class celery.utils.objects.getitem_property(keypath, doc=None)

Attribute -> dict key descriptor.

The target object must support __getitem__, and optionally __setitem__.

Example

>>> from collections import defaultdict

>>> class Me(dict):
...     deep = defaultdict(dict)
...
...     foo = _getitem_property('foo')
...     deep_thing = _getitem_property('deep.thing')

>>> me = Me()
>>> me.foo
None

>>> me.foo = 10
>>> me.foo
10
>>> me['foo']
10

>>> me.deep_thing = 42
>>> me.deep_thing
42
>>> me.deep
defaultdict(<type 'dict'>, {'thing': 42})

celery.utils.objects.mro_lookup(cls, attr, stop=None, monkey_patched=None)

Return the first node by MRO order that defines an attribute.

Parameters:

• cls (Any) – Child class to traverse.

• attr (str) – Name of attribute to find.

• stop (Set[Any]) – A set of types that if reached will stop the search.

• monkey_patched (Sequence) – Use one of the stop classes if the attributes module origin isn’t in this list. Used to detect monkey patched attributes.

Returns:

The attribute value, or None if not found.

Return type:

Any