Hi all,
I'm having some issues with integrating automatic group messaging based on
a post save signal from Django models.
I'm currently running a Graphene environment (graphene-python.org) to
support a webapp running React/Relay. In this setup we're performing
*Mutations* which will manipulate data, and return a payload based on the
data that was mutated. During a data mutation process I'm saving a model,
which triggers a post_save, which in turn seems to hijack the process and
terminate it, before the mutation can return its payload.
I have a simple JsonWebsocketConsumer to handle my connections.
class MyConsumers(JsonWebsocketConsumer):
channel_session_user = True
strict_ordering = True
method_mapping = {
"websocket.connect": "connect",
"websocket.receive": "receive",
"websocket.disconnect": "disconnect",
}
def connection_groups(self, **kwargs):
return ["all-clients", ]
def connect(self, message, **kwargs):
# Accepts connections and returns {'Accepted': Trie}
subscription_manager.SubscriptionManager.connect_endpoint(message)
def receive(self, content, **kwargs):
# Registers groups and stores data in redis cache.
subscription_manager.SubscriptionManager.receive_endpoint(content)
def disconnect(self, message, **kwargs):
...
A mutation comes in through urls as a normal http-request (through the
/graphql match):
urlpatterns = [
...
url(r'^graphql',
csrf_exempt(GraphQLView.as_view(graphiql=settings.DEBUG))),
url(r'^admin/', admin.site.urls),
url(r'^support/', include(support_urls)),
url(r'^django-rq/', include('django_rq.urls')),
]
The routing is as simple as can be:
subscription_routing = [
route_class(consumers.QuantumConsumers)
]
channel_routing = [
include(subscription_routing, path=r"^/ws/subscriptions"),
]
The post save is attached through a util on each model:
class Ping(models.Model):
support_session = models.OneToOneField(SupportSession,
related_name="ping")
client_ping = models.DateTimeField(...)
support_ping = models.DateTimeField(...)
# Sets up a post_save
ModelSignalReceiver.connect_receivers(Ping)
Finally, a mutation is a simple method that executes a save:
class PingMutation(graphene.ClientIDMutation):
class Input:
support_session_id = graphene.ID()
ping = graphene.Field(PingNode)
@classmethod
def mutate_and_get_payload(cls, args, context, info):
session_id = from_global_id(args.get('support_session_id'))[1]
pings =
support_models.Ping.objects.get(support_session__id=session_id)
pings.support_last_ping = datetime.datetime.now()
# I can see this debug message, before the save.
logger.debug('SupportPingMutation:pre-save')
# Will trigger the signal...
pings.save()
# The code never reaches this point.
logger.debug('SupportPingMutation:post-save')
return cls(ping=pings)
Any ideas on why the process gets hijacked? Should the post_save which
triggers a consumer response not be dispatched?
Thank you in advance.
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