def __new__(cls, name, bases, attrs): new = super(TaskType, cls).__new__ task_module = attrs.get('__module__') or '__main__' # - Abstract class: abstract attribute should not be inherited. abstract = attrs.pop('abstract', None) if abstract or not attrs.get('autoregister', True): return new(cls, name, bases, attrs) # The 'app' attribute is now a property, with the real app located # in the '_app' attribute. Previously this was a regular attribute, # so we should support classes defining it. app = attrs.pop('_app', None) or attrs.pop('app', None) # Attempt to inherit app from one the bases if not isinstance(app, Proxy) and app is None: for base in bases: if getattr(base, '_app', None): app = base._app break else: app = current_app._get_current_object() attrs['_app'] = app # - Automatically generate missing/empty name. task_name = attrs.get('name') if not task_name: attrs['name'] = task_name = gen_task_name(app, name, task_module) if not attrs.get('_decorated'): # non decorated tasks must also be shared in case # an app is created multiple times due to modules # imported under multiple names. # Hairy stuff, here to be compatible with 2.x. # People should not use non-abstract task classes anymore, # use the task decorator. from celery.app.builtins import shared_task unique_name = '.'.join([task_module, name]) if unique_name not in cls._creation_count: # the creation count is used as a safety # so that the same task is not added recursively # to the set of constructors. cls._creation_count[unique_name] = 1 shared_task(_CompatShared( unique_name, lambda app: TaskType.__new__(cls, name, bases, dict(attrs, _app=app)), )) # - Create and register class. # Because of the way import happens (recursively) # we may or may not be the first time the task tries to register # with the framework. There should only be one class for each task # name, so we always return the registered version. tasks = app._tasks if task_name not in tasks: tasks.register(new(cls, name, bases, attrs)) instance = tasks[task_name] instance.bind(app) return instance.__class__