Refactor DeploymentState creation

feudal/backend/models/deployments.py

@@ -226,19 +226,9 @@ class VODeployment(Deployment):
         created_new_states = False
 
         for service in self.services:
-            state, created = DeploymentState.objects.get_or_create(
-                user=self.user,
-                userinfo=self.user.userinfo,
-                site=service.site,
-                service=service,
-                service_name=service.name,
-            )
+            _, created = DeploymentState.get_or_create(self.user, service, self)
             if created:
-                LOGGER.debug(state.msg('Created'))
-
-            state.bind_to_deployment(self)  # make sure the state is bound to us
-
-            created_new_states = created
+                created_new_states = True
 
         return created_new_states
 
@@ -257,19 +247,9 @@ class VODeployment(Deployment):
 
     def service_added(self, service):
         LOGGER.debug(self.msg('Adding service {}'.format(service)))
-        state, created = DeploymentState.objects.get_or_create(
-            user=self.user,
-            userinfo=self.user.userinfo,
-            site=service.site,
-            service=service,
-            service_name=service.name,
-        )
-        if created:
-            LOGGER.debug(state.msg('Created'))
-
-        state.bind_to_deployment(self)  # make sure the state is bound to us
+        state, _ = DeploymentState.get_or_create(self.user, service, self)
 
-        if self.state_target == DEPLOYED:
+        if state is not None and self.state_target == DEPLOYED:
             state.publish_to_client()
             state.publish_to_user()
 
@@ -310,18 +290,7 @@ class ServiceDeployment(Deployment):
         raise ValueError('User is not permitted to have a deployment of this service!')
 
     def _assure_states_exist(self):
-        state, created = DeploymentState.objects.get_or_create(
-            user=self.user,
-            userinfo=self.user.userinfo,
-            site=self.service.site,
-            service=self.service,
-            service_name=self.service.name,
-        )
-        if created:
-            LOGGER.debug(state.msg('Created'))
-
-        state.bind_to_deployment(self)  # make sure the state is bound to us
-
+        _, created = DeploymentState.get_or_create(self.user, self.service, self)
         return created
 
     @classmethod
@@ -462,6 +431,34 @@ class DeploymentState(models.Model):
 
         return False
 
+    @classmethod
+    def get_or_create(cls, user, service, deployment):
+        try:
+            state, created = cls.objects.get_or_create(
+                user=user,
+                site=service.site,
+                service=service,
+                defaults={
+                    'userinfo': user.userinfo,
+                    'service_name': service.name,
+                }
+            )
+            if created:
+                LOGGER.debug(state.msg('Created'))
+                state.bind_to_deployment(deployment)
+
+            return state, created
+
+        except cls.MultipleObjectsReturned:
+            LOGGER.error(
+                'Multiple DeploymentStates for %s and %s and %s',
+                user,
+                service,
+                deployment,
+            )
+            return None, False
+
+
     # adds the deployment to our related deployments
     def bind_to_deployment(self, deployment):
         if not self.deployments.filter(id=deployment.id).exists():