change: log out details about PROMETHEUS_MULTIPROC_DIR

Additionally, respond with a 503 if the var is not set when
/metrics is requested.

Signed-off-by: Kevin Morris <kevr@0cost.org>

test/test_asgi.py

@@ -104,6 +104,17 @@ async def test_asgi_app_unsupported_backends():
             await aurweb.asgi.app_startup()
 
 
+@pytest.mark.asyncio
+async def test_asgi_app_disabled_metrics(caplog: pytest.LogCaptureFixture):
+    env = {"PROMETHEUS_MULTIPROC_DIR": str()}
+    with mock.patch.dict(os.environ, env):
+        await aurweb.asgi.app_startup()
+
+    expected = ("$PROMETHEUS_MULTIPROC_DIR is not set, the /metrics "
+                "endpoint is disabled.")
+    assert expected in caplog.text
+
+
 @pytest.fixture
 def use_traceback():
     config_getboolean = aurweb.config.getboolean

test/test_html.py

@@ -160,12 +160,23 @@ def test_archive_sig_404(client: TestClient):
 
 
 def test_metrics(client: TestClient):
-    with client as request:
-        resp = request.get("/metrics")
+    with tempfile.TemporaryDirectory() as tmpdir:
+        env = {"PROMETHEUS_MULTIPROC_DIR": tmpdir}
+        with mock.patch.dict(os.environ, env):
+            with client as request:
+                resp = request.get("/metrics")
     assert resp.status_code == int(HTTPStatus.OK)
     assert resp.headers.get("Content-Type").startswith("text/plain")
 
 
+def test_disabled_metrics(client: TestClient):
+    env = {"PROMETHEUS_MULTIPROC_DIR": str()}
+    with mock.patch.dict(os.environ, env):
+        with client as request:
+            resp = request.get("/metrics")
+    assert resp.status_code == int(HTTPStatus.SERVICE_UNAVAILABLE)
+
+
 def test_rtl(client: TestClient):
     responses = {}
     expected = [