feat(experimentation): one warehouse connection per environment

api/experimentation/migrations/0003_unique_connection_per_environment.py

@@ -0,0 +1,23 @@
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ("experimentation", "0002_add_config_and_created_status"),
+    ]
+
+    operations = [
+        migrations.RemoveConstraint(
+            model_name="warehouseconnection",
+            name="unique_active_warehouse_per_type_and_env",
+        ),
+        migrations.AddConstraint(
+            model_name="warehouseconnection",
+            constraint=models.UniqueConstraint(
+                condition=models.Q(("deleted_at__isnull", True)),
+                fields=("environment",),
+                name="unique_active_warehouse_per_env",
+            ),
+        ),
+    ]

api/experimentation/models.py

@@ -42,8 +42,8 @@ class WarehouseConnection(LifecycleModelMixin, SoftDeleteExportableModel):  # ty
     class Meta:
         constraints = [
             models.UniqueConstraint(
-                fields=["warehouse_type", "environment"],
+                fields=["environment"],
                 condition=models.Q(deleted_at__isnull=True),
-                name="unique_active_warehouse_per_type_and_env",
+                name="unique_active_warehouse_per_env",
             ),
         ]

api/experimentation/serializers.py

@@ -55,13 +55,14 @@ def create(
             WarehouseConnection.objects.all_with_deleted()
             .filter(
                 environment=environment,
-                warehouse_type=warehouse_type,
                 deleted_at__isnull=False,
             )
+            .order_by("-deleted_at")
             .first()
         )
         if existing:
             existing.deleted_at = None
+            existing.warehouse_type = warehouse_type
             existing.status = WarehouseConnectionStatus.CREATED
             existing.name = validated_data["name"]
             existing.config = validated_data.get("config")

api/experimentation/views.py

@@ -52,13 +52,13 @@ def create(self, request: Request, *args: object, **kwargs: object) -> Response:
         serializer = self.get_serializer(data=request.data)
         serializer.is_valid(raise_exception=True)
 
-        warehouse_type = serializer.validated_data["warehouse_type"]
         if WarehouseConnection.objects.filter(
             environment=environment,
-            warehouse_type=warehouse_type,
         ).exists():
             return Response(
-                {"detail": "Warehouse connection already exists."},
+                {
+                    "detail": "This environment already has an active warehouse connection."
+                },
                 status=409,
             )
 

api/tests/unit/experimentation/test_views.py

@@ -58,7 +58,39 @@ def test_post__already_exists__returns_409(
 
     # Then
     assert response.status_code == status.HTTP_409_CONFLICT
-    assert response.json()["detail"] == "Warehouse connection already exists."
+    assert (
+        response.json()["detail"]
+        == "This environment already has an active warehouse connection."
+    )
+
+
+def test_post__different_type_already_exists__returns_409(
+    admin_client: APIClient,
+    environment: Environment,
+    enable_features: EnableFeaturesFixture,
+    warehouse_connection: WarehouseConnection,
+    warehouse_connection_url: str,
+) -> None:
+    # Given
+    enable_features("experimentation_warehouse_connection")
+
+    # When
+    response = admin_client.post(
+        warehouse_connection_url,
+        data={
+            "warehouse_type": "snowflake",
+            "name": "My Snowflake",
+            "config": {"account_identifier": "xy12345.us-east-1"},
+        },
+        format="json",
+    )
+
+    # Then
+    assert response.status_code == status.HTTP_409_CONFLICT
+    assert (
+        response.json()["detail"]
+        == "This environment already has an active warehouse connection."
+    )
 
 
 def test_post__soft_deleted_exists__resurrects_and_returns_201(