feat: add endpoint to revert v2 versioning

api/environments/models.py

@@ -19,7 +19,6 @@
     AFTER_DELETE,
     AFTER_SAVE,
     AFTER_UPDATE,
-    BEFORE_UPDATE,
     LifecycleModel,
     hook,
 )
@@ -44,7 +43,6 @@
 from environments.exceptions import EnvironmentHeaderNotPresentError
 from environments.managers import EnvironmentManager
 from features.models import Feature, FeatureSegment, FeatureState
-from features.versioning.exceptions import FeatureVersioningError
 from metadata.models import Metadata
 from projects.models import IdentityOverridesV2MigrationStatus, Project
 from segments.models import Segment
@@ -150,10 +148,6 @@ def clear_environment_cache(self):
         # TODO: this could rebuild the cache itself (using an async task)
         environment_cache.delete(self.initial_value("api_key"))
 
-    @hook(BEFORE_UPDATE, when="use_v2_feature_versioning", was=True, is_now=False)
-    def validate_use_v2_feature_versioning(self):
-        raise FeatureVersioningError("Cannot revert from v2 feature versioning.")
-
     @hook(AFTER_DELETE)
     def delete_from_dynamo(self):
         if self.project.enable_dynamo_db and environment_wrapper.is_enabled:

api/environments/views.py

@@ -17,7 +17,10 @@
     NestedEnvironmentPermissions,
 )
 from environments.sdk.schemas import SDKEnvironmentDocumentModel
-from features.versioning.tasks import enable_v2_versioning
+from features.versioning.tasks import (
+    disable_v2_versioning,
+    enable_v2_versioning,
+)
 from permissions.permissions_calculator import get_environment_permission_data
 from permissions.serializers import (
     PermissionModelSerializer,
@@ -216,6 +219,18 @@ def enable_v2_versioning(self, request: Request, api_key: str) -> Response:
         enable_v2_versioning.delay(kwargs={"environment_id": environment.id})
         return Response(status=status.HTTP_202_ACCEPTED)
 
+    @swagger_auto_schema(request_body=no_body, responses={202: ""})
+    @action(detail=True, methods=["POST"], url_path="disable-v2-versioning")
+    def disable_v2_versioning(self, request: Request, api_key: str) -> Response:
+        environment = self.get_object()
+        if environment.use_v2_feature_versioning is False:
+            return Response(
+                status=status.HTTP_400_BAD_REQUEST,
+                data={"detail": "Environment is not using v2 versioning."},
+            )
+        disable_v2_versioning.delay(kwargs={"environment_id": environment.id})
+        return Response(status=status.HTTP_202_ACCEPTED)
+
 
 class NestedEnvironmentViewSet(viewsets.GenericViewSet):
     model_class = None

api/features/versioning/tasks.py

@@ -24,7 +24,7 @@
 
 
 @register_task_handler()
-def enable_v2_versioning(environment_id: int):
+def enable_v2_versioning(environment_id: int) -> None:
     from environments.models import Environment
 
     environment = Environment.objects.get(id=environment_id)
@@ -35,6 +35,33 @@ def enable_v2_versioning(environment_id: int):
     environment.save()
 
 
+@register_task_handler()
+def disable_v2_versioning(environment_id: int) -> None:
+    from environments.models import Environment
+    from features.models import FeatureState
+    from features.versioning.models import EnvironmentFeatureVersion
+
+    environment = Environment.objects.get(id=environment_id)
+
+    latest_feature_states = get_environment_flags_queryset(environment)
+
+    # delete any feature states associated with older versions
+    FeatureState.objects.filter(identity_id__isnull=True).exclude(
+        id__in=[fs.id for fs in latest_feature_states]
+    ).delete()
+
+    # update the latest feature states to be the latest version according
+    # to the old versioning system
+    latest_feature_states.update(
+        version=1, live_from=timezone.now(), environment_feature_version=None
+    )
+
+    EnvironmentFeatureVersion.objects.filter(environment=environment).delete()
+
+    environment.use_v2_feature_versioning = False
+    environment.save()
+
+
 def _create_initial_feature_versions(environment: "Environment"):
     from features.models import Feature, FeatureSegment
 

api/tests/integration/features/versioning/test_integration_v2_versioning.py

@@ -196,7 +196,7 @@ def verify_consistent_responses(num_expected_flags: int) -> None:
     # still behave the same
     verify_consistent_responses(num_expected_flags=2)
 
-    # finally, let's publish the new version and verify that we get a different response
+    # now, let's publish the new version and verify that we get a different response
     publish_ef_version_url = reverse(
         "api-v1:versioning:environment-feature-versions-publish",
         args=[environment, feature, ef_version_uuid],
@@ -237,6 +237,45 @@ def verify_consistent_responses(num_expected_flags: int) -> None:
         == "v2-segment-override-value"
     )
 
+    # finally, let's test that we can revert the v2 versioning, and we still get the
+    # same response
+    disable_versioning_url = reverse(
+        "api-v1:environments:environment-disable-v2-versioning",
+        args=[environment_api_key],
+    )
+    environment_update_response = admin_client.post(disable_versioning_url)
+    assert environment_update_response.status_code == status.HTTP_202_ACCEPTED
+
+    time.sleep(0.5)
+
+    environment_flags_response_after_revert = get_environment_flags_response_json(
+        num_expected_flags=2
+    )
+    identity_flags_response_after_revert = get_identity_flags_response_json(
+        num_expected_flags=2
+    )
+
+    # Verify that the environment flags have the same state / value
+    environment_flag_tuples_pre_revert = {
+        (f["enabled"], f["feature_state_value"], f["feature"]["id"])
+        for f in environment_flags_response_json_after_publish
+    }
+    environment_flag_tuples_post_revert = {
+        (f["enabled"], f["feature_state_value"], f["feature"]["id"])
+        for f in environment_flags_response_after_revert
+    }
+    assert environment_flag_tuples_pre_revert == environment_flag_tuples_post_revert
+
+    identity_flag_tuples_pre_revert = {
+        (f["enabled"], f["feature_state_value"], f["feature"]["id"])
+        for f in identity_flags_response_json_after_publish["flags"]
+    }
+    identity_flag_tuples_post_revert = {
+        (f["enabled"], f["feature_state_value"], f["feature"]["id"])
+        for f in identity_flags_response_after_revert["flags"]
+    }
+    assert identity_flag_tuples_pre_revert == identity_flag_tuples_post_revert
+
 
 def test_v2_versioning_mv_feature(
     admin_client: "APIClient",