Refactor minor details

django_backend/backend/models.py

@@ -39,19 +39,6 @@ def questionnaire_default():
 def credential_default():
     return {}
 
-# takes a list of states
-# return '<state>' if all states are equal to '<state>'
-# else it returns 'mixed'
-def analyze_states(states):
-    _state = ''
-    for state in states:
-        if _state == '':
-            _state = state
-        elif _state != state:
-            return 'mixed'
-
-    return _state
-
 
 # singleton for simple configs
 # https://steelkiwi.com/blog/practical-application-singleton-design-pattern/
@@ -529,9 +516,12 @@ class Service(models.Model):
 
                 # all group deployments have the same keys
                 # TODO check that assumption
-                deployment = user.deployments.filter(group=group)
-                if deployment.exists():
-                    deployment.first().service_added(self)
+                try:
+                    deployment = user.deployments.get(group=group)
+                    deployment.service_added(self)
+                except Deployment.DoesNotExist:
+                    LOGGER.error('Inconsistency in group deployment')
+                    raise
 
 
 class SSHPublicKey(models.Model):
@@ -817,7 +807,22 @@ class DeploymentState(models.Model):
 
     @property
     def state(self):
-        return analyze_states(self.states)
+        if self.states:
+            _state = ''
+            for state in self.states:
+                if _state == '':
+                    _state = state
+                elif _state != state:
+                    return 'mixed'
+
+            return _state
+
+        # if we have no states we have nothing to do
+        return self.state_target
+
+    @property
+    def target_reached(self):
+        return self.state_target == self.state
 
     @property
     def service(self):
@@ -831,10 +836,6 @@ class DeploymentState(models.Model):
     def group(self):
         return self.deployment.group
 
-    @property
-    def target_reached(self):
-        return self.state_target == self.state
-
     # get a state for a user/service.
     # if it does not exist it is created
     @classmethod