Django Channels Rest Framework V3 #model_observer message is None - django

Question

I tried to find anything in the documentation of model observer which could explain under which conditions the model observer is called with message = None, but there was nothing particularly hinting into the right direction. From what I unterstand from the example:
class MyConsumer(GenericAsyncAPIConsumer):
queryset = User.objects.all()
serializer_class = UserSerializer
#model_observer(Comments)
async def comment_activity(
self,
message: CommentSerializer,
observer=None,
subscribing_request_ids=[]
**kwargs
):
await self.send_json(message.data)
#comment_activity.serializer
def comment_activity(self, instance: Comment, action, **kwargs) -> CommentSerializer:
'''This will return the comment serializer'''
return CommentSerializer(instance)
#action()
async def subscribe_to_comment_activity(self, request_id, **kwargs):
await self.comment_activity.subscribe(request_id=request_id)
The message should be the output of the CommentSerializer so the only way a message to become null is, if the serializer would return nothing ?!
To check if this is the case I added logs prints which sadly indicate that the serializer is receiving data and thous there is no reason the message could be None.
Its also occurring only from time to time so any advice about misunderstanding of how the observer works internally will be highly appreciated.
In our implementation:
class StorageConsumer(ListModelMixin, AsyncAPIConsumer):
"""
Async API endpoint that allows Storage updates to be pushed.
"""
async def accept(self, **kwargs):
await super().accept()
await self.model_change_bess.subscribe()
#model_observer(Bess)
async def model_change_bess(self, message, **kwargs):
if message is None:
logger.warning(f"model_change_bess change without a message")
return
message["model"] = kwargs["observer"].model_cls.__name__
await self.send_json(message)
#model_change_bess.serializer
def model_serialize(self, instance, action, **kwargs):
data = BessSerializer(instance).data
# TODO remove once the message is None bug is fixed
logger.info(f"model_serialize bess instance: {instance} data: {data}")
serialized_data = {
"project_id": data["project"],
"simulation_id": data["simulation"],
"data": data,
}
return serialized_data
the corresponding logs in case message is None looks like this:
16/06/2022 13:09:25 [INFO] api_consumers: model_serialize bess instance: Bess object (37227) data: {'id': 37227, 'created': '2022-06-16T13:09:25Z', 'modified': '2022-06-16T13:09:25Z', 'time_stamp': '2022-06-16T13:09:25Z', 'cycles': '0.02541166724274896000000000000000', 'p_bess': '-74.0000', 'soc': '0.45109075850806520000000000000000', 'soh': '0.99514591796314000000000000000000', 'temperature_bess': None, 'time_to_eol': None, 'feedback': True, 'project': 1, 'simulation': 1}
16/06/2022 13:09:25 [WARNING] api_consumers: model_change_bess change without a message