Add kubernetes health check endpoint to server

python/lsst/daf/butler/remote_butler/server/_server.py

@@ -36,6 +36,7 @@
 from fastapi import Depends, FastAPI
 from fastapi.middleware.gzip import GZipMiddleware
 from lsst.daf.butler import Butler
+from safir.metadata import Metadata, get_metadata
 
 from ._config import get_config_from_env
 from ._factory import Factory
@@ -56,6 +57,26 @@ def factory_dependency() -> Factory:
     return Factory(butler=_make_global_butler())
 
 
+@app.get(
+    "/",
+    description=(
+        "Return metadata about the running application. Can also be used as"
+        " a health check. This route is not exposed outside the cluster and"
+        " therefore cannot be used by external clients."
+    ),
+    include_in_schema=False,
+    response_model=Metadata,
+    response_model_exclude_none=True,
+    summary="Application metadata",
+)
+async def get_index() -> Metadata:
+    """GET ``/`` (the app's internal root).
+
+    By convention, this endpoint returns only the application's metadata.
+    """
+    return get_metadata(package_name="lsst.daf.butler", application_name="butler")
+
+
 @app.get("/butler/v1/universe", response_model=dict[str, Any])
 def get_dimension_universe(factory: Factory = Depends(factory_dependency)) -> dict[str, Any]:
     """Allow remote client to get dimensions definition."""

requirements.txt

@@ -21,3 +21,4 @@ pyarrow >= 0.16
 responses >= 0.12.0
 urllib3 >= 1.25.10
 fastapi
+safir >= 3.4.0

tests/test_server.py

@@ -82,6 +82,11 @@ def tearDownClass(cls):
         del app.dependency_overrides[factory_dependency]
         removeTestTempDir(cls.root)
 
+    def test_health_check(self):
+        response = self.client.get("/")
+        self.assertEqual(response.status_code, 200)
+        self.assertEqual(response.json()["name"], "butler")
+
     def test_simple(self):
         response = self.client.get("/butler/v1/universe")
         self.assertEqual(response.status_code, 200)