feat: add prometheus migration

selfprivacy_api/migrations/add_promiteus.py

@@ -0,0 +1,36 @@
+from selfprivacy_api.migrations.migration import Migration
+
+from selfprivacy_api.services.flake_service_manager import FlakeServiceManager
+from selfprivacy_api.utils import ReadUserData, WriteUserData
+
+
+class AddPrometheus(Migration):
+    """Adds the Prometheus if it is not present."""
+
+    def get_migration_name(self) -> str:
+        return "add_prometheus"
+
+    def get_migration_description(self) -> str:
+        return "Adds the Prometheus if it is not present."
+
+    def is_migration_needed(self) -> bool:
+        with FlakeServiceManager() as manager:
+            if "prometheus" not in manager.services:
+                return True
+        with ReadUserData() as data:
+            if "prometheus" not in data["modules"]:
+                return True
+        return False
+
+    def migrate(self) -> None:
+        with FlakeServiceManager() as manager:
+            if "prometheus" not in manager.services:
+                manager.services["prometheus"] = (
+                    "git+https://git.selfprivacy.org/SelfPrivacy/selfprivacy-nixos-config.git?ref=flakes&dir=sp-modules/prometheus"
+                )
+        with WriteUserData() as data:
+            if "prometheus" not in data["modules"]:
+                data["modules"]["prometheus"] = {
+                    "enable": False,
+                    "subdomain": "prometheus",
+                }