This document describes the current stable version of Celery (4.4). For development docs, go here.

Source code for celery.utils.abstract

# -*- coding: utf-8 -*-
"""Abstract classes."""
from __future__ import absolute_import, unicode_literals

from abc import ABCMeta, abstractmethod, abstractproperty

from celery.five import with_metaclass

    from import Callable
except ImportError:
    # TODO: Remove this when we drop Python 2.7 support
    from collections import Callable

__all__ = ('CallableTask', 'CallableSignature')

def _hasattr(C, attr):
    return any(attr in B.__dict__ for B in C.__mro__)

class _AbstractClass(object):
    __required_attributes__ = frozenset()

    def _subclasshook_using(cls, parent, C):
        return (
            cls is parent and
            all(_hasattr(C, attr) for attr in cls.__required_attributes__)
        ) or NotImplemented

    def register(cls, other):
        # we override `register` to return other for use as a decorator.
        type(cls).register(cls, other)
        return other

[docs]class CallableTask(_AbstractClass, Callable): # pragma: no cover """Task interface.""" __required_attributes__ = frozenset({ 'delay', 'apply_async', 'apply', })
[docs] @abstractmethod def delay(self, *args, **kwargs): pass
[docs] @abstractmethod def apply_async(self, *args, **kwargs): pass
[docs] @abstractmethod def apply(self, *args, **kwargs): pass
@classmethod def __subclasshook__(cls, C): return cls._subclasshook_using(CallableTask, C)
[docs]class CallableSignature(CallableTask): # pragma: no cover """Celery Signature interface.""" __required_attributes__ = frozenset({ 'clone', 'freeze', 'set', 'link', 'link_error', '__or__', }) @abstractproperty def name(self): pass @abstractproperty def type(self): pass @abstractproperty def app(self): pass @abstractproperty def id(self): pass @abstractproperty def task(self): pass @abstractproperty def args(self): pass @abstractproperty def kwargs(self): pass @abstractproperty def options(self): pass @abstractproperty def subtask_type(self): pass @abstractproperty def chord_size(self): pass @abstractproperty def immutable(self): pass
[docs] @abstractmethod def clone(self, args=None, kwargs=None): pass
[docs] @abstractmethod def freeze(self, id=None, group_id=None, chord=None, root_id=None): pass
[docs] @abstractmethod def set(self, immutable=None, **options): pass
@abstractmethod def __or__(self, other): pass @abstractmethod def __invert__(self): pass @classmethod def __subclasshook__(cls, C): return cls._subclasshook_using(CallableSignature, C)