feat: add fields necessary for stale flags

api/features/serializers.py

@@ -1,4 +1,5 @@
 import typing
+from datetime import datetime
 
 import django.core.exceptions
 from drf_writable_nested import WritableNestedModelSerializer
@@ -121,6 +122,18 @@ class ListCreateFeatureSerializer(DeleteBeforeUpdateWritableNestedModelSerialize
         "Note: will return null for Edge enabled projects."
     )
 
+    last_modified_in_any_environment = serializers.SerializerMethodField(
+        help_text="Datetime representing the last time that the feature was modified "
+        "in any environment in the given project. Note: requires feature "
+        "versioning v2 enabled on the environment."
+    )
+    last_modified_in_current_environment = serializers.SerializerMethodField(
+        help_text="Datetime representing the last time that the feature was modified "
+        "in any environment in the current environment. Note: requires that "
+        "the environment query parameter is passed and feature versioning v2 "
+        "enabled on the environment."
+    )
+
     class Meta:
         model = Feature
         fields = (
@@ -141,6 +154,8 @@ class Meta:
             "num_segment_overrides",
             "num_identity_overrides",
             "is_server_key_only",
+            "last_modified_in_any_environment",
+            "last_modified_in_current_environment",
         )
         read_only_fields = ("feature_segments", "created_date", "uuid", "project")
 
@@ -244,6 +259,16 @@ def get_num_identity_overrides(self, instance) -> typing.Optional[int]:
         except (KeyError, AttributeError):
             return None
 
+    def get_last_modified_in_any_environment(
+        self, instance: Feature
+    ) -> datetime | None:
+        return getattr(instance, "last_modified_in_any_environment", None)
+
+    def get_last_modified_in_current_environment(
+        self, instance: Feature
+    ) -> datetime | None:
+        return getattr(instance, "last_modified_in_current_environment", None)
+
 
 class UpdateFeatureSerializer(ListCreateFeatureSerializer):
     """prevent users from changing certain values after creation"""

api/features/views.py

@@ -8,7 +8,7 @@
 from core.request_origin import RequestOrigin
 from django.conf import settings
 from django.core.cache import caches
-from django.db.models import Q, QuerySet
+from django.db.models import Max, Q, QuerySet
 from django.utils.decorators import method_decorator
 from django.views.decorators.cache import cache_page
 from drf_yasg import openapi
@@ -117,8 +117,18 @@ def get_queryset(self):
         accessible_projects = self.request.user.get_permitted_projects(VIEW_PROJECT)
 
         project = get_object_or_404(accessible_projects, pk=self.kwargs["project_pk"])
-        queryset = project.features.all().prefetch_related(
-            "multivariate_options", "owners", "tags", "group_owners"
+
+        queryset = (
+            project.features.all()
+            .annotate(
+                last_modified_in_any_environment=Max(
+                    "feature_states__environment_feature_version__created_at",
+                    filter=Q(
+                        feature_states__environment_feature_version__published_at__isnull=False
+                    ),
+                ),
+            )
+            .prefetch_related("multivariate_options", "owners", "tags", "group_owners")
         )
 
         query_serializer = FeatureQuerySerializer(data=self.request.query_params)
@@ -127,6 +137,17 @@ def get_queryset(self):
 
         queryset = self._filter_queryset(queryset)
 
+        if environment_id := query_data.get("environment"):
+            queryset = queryset.annotate(
+                last_modified_in_current_environment=Max(
+                    "feature_states__environment_feature_version__created_at",
+                    filter=Q(
+                        feature_states__environment=environment_id,
+                        feature_states__environment_feature_version__published_at__isnull=False,
+                    ),
+                )
+            )
+
         sort = "%s%s" % (
             "-" if query_data["sort_direction"] == "DESC" else "",
             query_data["sort_field"],

api/projects/migrations/0022_add_stale_flags_threshold_to_project.py

@@ -0,0 +1,19 @@
+# Generated by Django 3.2.23 on 2023-12-06 14:35
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+    dependencies = [
+        ("projects", "0021_add_identity_overrides_migration_status"),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name="project",
+            name="stale_flags_limit_days",
+            field=models.IntegerField(
+                default=30,
+                help_text="Number of days without modification in any environment before a flag is considered stale.",
+            ),
+        ),
+    ]

api/projects/models.py

@@ -87,6 +87,10 @@ class Project(LifecycleModelMixin, SoftDeleteExportableModel):
         choices=IdentityOverridesV2MigrationStatus.choices,
         default=IdentityOverridesV2MigrationStatus.NOT_STARTED,
     )
+    stale_flags_limit_days = models.IntegerField(
+        default=30,
+        help_text="Number of days without modification in any environment before a flag is considered stale.",
+    )
 
     objects = ProjectManager()
 

api/projects/tags/migrations/0005_add_tag_fields_for_stale_flags_logic.py

@@ -0,0 +1,75 @@
+# Generated by Django 3.2.23 on 2023-12-06 15:11
+import re
+
+from django.apps.registry import Apps
+from django.db import migrations, models
+from django.db.backends.base.schema import BaseDatabaseSchemaEditor
+
+
+PROTECTED_LABELS = {"protected", "donotdelete", "permanent"}
+LABEL_REGEX = re.compile(r"[ _]")
+
+
+def get_sanitised_label(label: str) -> str:
+    return LABEL_REGEX.sub("", label.lower())
+
+
+def mark_existing_tags_as_permanent(
+    apps: Apps, schema_editor: BaseDatabaseSchemaEditor
+) -> None:
+    """
+    Update all tags in the database which the FE treats as 'permanent' through regex matching
+    to have the new is_permanent label. The FE will subsequently be updated to use the
+    is_permanent attribute instead of regex matching.
+    """
+    tag_class = apps.get_model("tags", "tag")
+
+    to_update = []
+
+    for tag in filter(
+        lambda t: get_sanitised_label(t.label) in PROTECTED_LABELS,
+        tag_class.objects.all(),
+    ):
+        tag.is_permanent = True
+        to_update.append(tag)
+
+    tag_class.objects.bulk_update(to_update, fields=["is_permanent"])
+
+
+class Migration(migrations.Migration):
+    dependencies = [
+        ("tags", "0004_add_uuid_field"),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name="tag",
+            name="is_permanent",
+            field=models.BooleanField(
+                default=False,
+                help_text="When applied to a feature, it means this feature should be excluded from stale flags logic.",
+            ),
+        ),
+        migrations.AddField(
+            model_name="tag",
+            name="is_system_tag",
+            field=models.BooleanField(
+                default=False,
+                help_text="Indicates that a tag was created by the system, not the user.",
+            ),
+        ),
+        migrations.RunPython(
+            mark_existing_tags_as_permanent, reverse_code=migrations.RunPython.noop
+        ),
+        migrations.AddField(
+            model_name="tag",
+            name="type",
+            field=models.CharField(
+                default=None,
+                null=True,
+                choices=(("STALE", "Stale"),),
+                help_text="Field used to provide a consistent identifier for the FE and API to use for business logic.",
+                max_length=100,
+            )
+        ),
+    ]

api/projects/tags/models.py

@@ -4,6 +4,10 @@
 from projects.models import Project
 
 
+class TagType(models.Choices):
+    STALE = "STALE"
+
+
 class Tag(AbstractBaseExportableModel):
     label = models.CharField(max_length=100)
     color = models.CharField(
@@ -12,6 +16,22 @@ class Tag(AbstractBaseExportableModel):
     description = models.CharField(max_length=512, blank=True, null=True)
     project = models.ForeignKey(Project, on_delete=models.CASCADE, related_name="tags")
 
+    is_system_tag = models.BooleanField(
+        default=False,
+        help_text="Indicates that a tag was created by the system, not the user.",
+    )
+    is_permanent = models.BooleanField(
+        default=False,
+        help_text="When applied to a feature, it means this feature should be excluded from stale flags logic.",
+    )
+    type = models.CharField(
+        default=None,
+        null=True,
+        choices=TagType.choices,
+        help_text="Field used to provide a consistent identifier for the FE and API to use for business logic.",
+        max_length=100,
+    )
+
     class Meta:
         ordering = ("id",)  # explicit ordering to prevent pagination warnings
 

api/projects/tags/serializers.py

@@ -6,5 +6,15 @@
 class TagSerializer(serializers.ModelSerializer):
     class Meta:
         model = Tag
-        fields = ("id", "label", "color", "description", "project", "uuid")
-        read_only_fields = ("project",)
+        fields = (
+            "id",
+            "label",
+            "color",
+            "description",
+            "project",
+            "uuid",
+            "is_permanent",
+            "is_system_tag",
+            "type",
+        )
+        read_only_fields = ("project", "uuid", "is_system_tag", "type")

api/tests/integration/features/featurestate/test_environment_featurestate_viewset.py

@@ -34,4 +34,4 @@ def test_update_feature_state_value_updates_feature_state_value(
 
     # Then
     assert response.status_code == status.HTTP_200_OK
-    response.json()["feature_state_value"] == new_value
+    assert response.json()["feature_state_value"] == new_value

api/tests/unit/features/test_unit_features_views.py

@@ -10,6 +10,7 @@
 from django.forms import model_to_dict
 from django.urls import reverse
 from django.utils import timezone
+from freezegun import freeze_time
 from pytest_django import DjangoAssertNumQueries
 from pytest_lazyfixture import lazy_fixture
 from rest_framework import status
@@ -55,6 +56,10 @@
 # patch this function as it's triggering extra threads and causing errors
 mock.patch("features.signals.trigger_feature_state_change_webhooks").start()
 
+now = timezone.now()
+two_hours_ago = now - timedelta(hours=2)
+one_hour_ago = now - timedelta(hours=1)
+
 
 @pytest.mark.django_db
 class ProjectFeatureTestCase(TestCase):
@@ -2554,3 +2559,66 @@ def test_simple_feature_state_returns_only_latest_versions(
 
     response_json = response.json()
     assert response_json["count"] == 2
+
+
+@pytest.mark.freeze_time(two_hours_ago)
+def test_feature_list_last_modified_values(
+    staff_client: APIClient,
+    staff_user: FFAdminUser,
+    environment_v2_versioning: Environment,
+    project: Project,
+    feature: Feature,
+    with_project_permissions: WithProjectPermissionsCallable,
+    django_assert_num_queries: DjangoAssertNumQueries,
+) -> None:
+    # Given
+    # another v2 versioning environment
+    environment_v2_versioning_2 = Environment.objects.create(
+        name="environment 2", project=project, use_v2_feature_versioning=True
+    )
+
+    url = "{base_url}?environment={environment_id}".format(
+        base_url=reverse("api-v1:projects:project-features-list", args=[project.id]),
+        environment_id=environment_v2_versioning.id,
+    )
+
+    with_project_permissions([VIEW_PROJECT])
+
+    with freeze_time(one_hour_ago):
+        # create a new published version in another environment, simulated to be one hour ago
+        environment_v2_versioning_2_version_2 = (
+            EnvironmentFeatureVersion.objects.create(
+                environment=environment_v2_versioning_2, feature=feature
+            )
+        )
+        environment_v2_versioning_2_version_2.publish(staff_user)
+
+    with freeze_time(now):
+        # and create a new unpublished version in the current environment, simulated to be now
+        # this shouldn't affect the values returned
+        EnvironmentFeatureVersion.objects.create(
+            environment=environment_v2_versioning, feature=feature
+        )
+
+    # let's add a few more features to ensure we aren't adding N+1 issues
+    for i in range(2):
+        Feature.objects.create(name=f"feature_{i}", project=project)
+
+    # When
+    with django_assert_num_queries(14):  # TODO: reduce this number of queries!
+        response = staff_client.get(url)
+
+    # Then
+    assert response.status_code == status.HTTP_200_OK
+
+    response_json = response.json()
+    assert response_json["count"] == 3
+
+    feature_data = next(
+        filter(lambda r: r["id"] == feature.id, response_json["results"])
+    )
+    assert feature_data["last_modified_in_any_environment"] == one_hour_ago.isoformat()
+    assert (
+        feature_data["last_modified_in_current_environment"]
+        == two_hours_ago.isoformat()
+    )