outposts: handle disconnects without outpost better

Signed-off-by: Jens Langhammer <jens.langhammer@beryju.org>

authentik/outposts/channels.py

@@ -50,7 +50,7 @@ class WebsocketMessage:
 class OutpostConsumer(AuthJsonConsumer):
     """Handler for Outposts that connect over websockets for health checks and live updates"""
 
-    outpost: Outpost
+    outpost: Optional[Outpost] = None
 
     last_uid: Optional[str] = None
 
@@ -95,6 +95,9 @@ class OutpostConsumer(AuthJsonConsumer):
         uid = msg.args.get("uuid", self.channel_name)
         self.last_uid = uid
 
+        if not self.outpost:
+            raise DenyConnection()
+
         state = OutpostState.for_instance_uid(self.outpost, uid)
         if self.channel_name not in state.channel_ids:
             state.channel_ids.append(self.channel_name)