Additional refactoring + fixing post merge

api/features/versioning/exceptions.py

@@ -0,0 +1,5 @@
+from rest_framework.exceptions import APIException
+
+
+class FeatureVersioningError(APIException):
+    pass

api/features/versioning/models.py

@@ -12,6 +12,7 @@
 
 from environments.models import Environment
 from features.models import Feature, FeatureState
+from features.versioning.exceptions import FeatureVersioningError
 
 
 class EnvironmentFeatureVersion(LifecycleModel):
@@ -58,6 +59,11 @@ def generate_sha(self):
             f"{self.environment.id}{self.feature.id}{time.time()}".encode("utf-8")
         ).hexdigest()
 
+    @hook(BEFORE_CREATE, when="published", is_now=True)
+    def update_live_from(self):
+        if not self.live_from:
+            self.live_from = timezone.now()
+
     @property
     def is_live(self):
         return self.published and self.live_from < timezone.now()
@@ -72,21 +78,15 @@ def create_initial_version(
         """
 
         if not environment.use_v2_feature_versioning:
-            # TODO: custom exception
-            raise Exception()
+            raise FeatureVersioningError(
+                "Cannot create initial version for environment using v1 versioning."
+            )
         elif cls.objects.filter(environment=environment, feature=feature).exists():
-            # TODO: custom exception
-            raise Exception()
-
-        version = cls.objects.create(environment=environment, feature=feature)
-        FeatureState.objects.filter(
-            environment=environment, feature=feature, identity=None
-        ).update(environment_feature_version=version)
-
-        version.publish()
-        version.save()
+            raise FeatureVersioningError(
+                "Version already exists for this feature / environment combination."
+            )
 
-        return version
+        return cls.objects.create(environment=environment, feature=feature, published=True)
 
     def get_previous_version(self) -> typing.Optional["EnvironmentFeatureVersion"]:
         return (

api/features/versioning/serializers.py

@@ -1,10 +1,36 @@
+from datetime import datetime
+
+from rest_framework.exceptions import ValidationError
 from rest_framework.serializers import ModelSerializer
 
+from features.serializers import CreateSegmentOverrideFeatureStateSerializer
 from features.versioning.models import EnvironmentFeatureVersion
 
 
+class EnvironmentFeatureVersionFeatureStateSerializer(
+    CreateSegmentOverrideFeatureStateSerializer
+):
+    class Meta(CreateSegmentOverrideFeatureStateSerializer.Meta):
+        read_only_fields = (
+            CreateSegmentOverrideFeatureStateSerializer.Meta.read_only_fields
+            + ("feature",)
+        )
+
+
 class EnvironmentFeatureVersionSerializer(ModelSerializer):
     class Meta:
         model = EnvironmentFeatureVersion
         fields = ("created_at", "updated_at", "published", "live_from", "sha")
-        read_only_fields = ("published", "updated_at", "created_at", "sha")
+        read_only_fields = ("updated_at", "created_at", "sha")
+
+    def validate_published(self, published: bool) -> None:
+        if instance := getattr(self, "instance", None):
+            if instance.is_live and published is False:
+                raise ValidationError("Cannot un-publish already live version")
+
+    def validate_live_from(self, live_from: datetime) -> None:
+        if instance := getattr(self, "instance", None):
+            if instance.is_live and live_from != instance.live_from:
+                raise ValidationError(
+                    "Cannot change 'live from' date of already live version."
+                )

api/features/versioning/views.py

@@ -15,8 +15,10 @@
 from environments.models import Environment
 from features.models import Feature, FeatureState
 from features.serializers import CreateSegmentOverrideFeatureStateSerializer
+from features.versioning.exceptions import FeatureVersioningError
 from features.versioning.models import EnvironmentFeatureVersion
-from features.versioning.serializers import EnvironmentFeatureVersionSerializer
+from features.versioning.serializers import EnvironmentFeatureVersionSerializer, \
+    EnvironmentFeatureVersionFeatureStateSerializer
 
 
 class EnvironmentFeatureVersionViewSet(
@@ -49,6 +51,12 @@ def perform_create(self, serializer: Serializer) -> None:
     def perform_update(self, serializer: Serializer) -> None:
         serializer.save(environment=self.environment, feature=self.feature)
 
+    def perform_destroy(self, instance: EnvironmentFeatureVersion) -> None:
+        if instance.is_live:
+            raise FeatureVersioningError("Cannot delete a live version.")
+
+        super().perform_destroy(instance)
+
     @action(detail=True, methods=["POST"])
     def publish(self, request: Request, **kwargs) -> Response:
         ef_version = self.get_object()
@@ -64,7 +72,7 @@ class EnvironmentFeatureVersionFeatureStatesViewSet(
     UpdateModelMixin,
     DestroyModelMixin,  # TODO: prevent deletion, update for published versions?
 ):
-    serializer_class = CreateSegmentOverrideFeatureStateSerializer
+    serializer_class = EnvironmentFeatureVersionFeatureStateSerializer
     permission_classes = [IsAuthenticated]  # TODO
     pagination_class = None
 
@@ -79,13 +87,16 @@ def get_queryset(self):
 
     def initial(self, request: Request, *args, **kwargs):
         super().initial(request, *args, **kwargs)
+        self.environment_feature_version = get_object_or_404(
+            EnvironmentFeatureVersion, sha=self.kwargs["environment_feature_version_pk"]
+        )
+        if self.action != "list" and self.environment_feature_version.published is True:
+            raise FeatureVersioningError("Cannot modify published version.")
+
         self.environment = get_object_or_404(
             Environment, pk=self.kwargs["environment_pk"]
         )
         self.feature = get_object_or_404(Feature, pk=self.kwargs["feature_pk"])
-        self.environment_feature_version = get_object_or_404(
-            EnvironmentFeatureVersion, sha=self.kwargs["environment_feature_version_pk"]
-        )
 
     def get_serializer_context(self):
         context = super().get_serializer_context()

api/tests/unit/features/versioning/test_unit_versioning_versioning.py

@@ -80,7 +80,7 @@ def test_get_environment_flags_returns_latest_live_versions_of_feature_states(
     FeatureState.objects.create(
         feature=feature,
         enabled=False,
-        version=3,
+        version=None,
         environment=environment,
     )