Tell polling clients when we've recreated their connection and they need to resubscribe.

api.py

@@ -75,6 +75,7 @@ def Poll(google_user, client, client_address, instance_id, args):
 
   return {
     'result': 'ok',
+    'new': instance.newly_created,
     'events': events,
   }
 
@@ -161,7 +162,6 @@ def Subscribe(google_user, client, client_address, instance_id, args):
       'result': 'access_denied',
     }
 
-
   if not instance or not instance.active:
     # Probably a race with the channel opening
     return {

lib/models.py

@@ -104,7 +104,16 @@ class Instance(db.Model):
   @classmethod
   def FindOrCreate(cls, instance_id, **kwargs):
     logging.info('Instance: %s', instance_id)
-    return cls.get_or_insert(instance_id, **kwargs)
+    def _FindOrCreate():
+      entity = cls.get_by_key_name(instance_id)
+      if entity:
+        entity.newly_created = False
+        return entity
+      entity = cls(key_name=instance_id, **kwargs)
+      entity.put()
+      entity.newly_created = True
+      return entity
+    return db.run_in_transaction(_FindOrCreate)
 
   def Delete(self):
     logging.info('Deleting instance %s', self.key().name())