Frontend service: add empty health route (#112212)

* add empty health route to frontend-service

* add OK response

* add test

* handle error case

pkg/services/frontend/frontend_service.go

@@ -138,6 +138,16 @@ func (s *frontendService) registerRoutes(m *web.Mux) {
 	// them so we can get logs for them
 	s.routeGet(m, "/public/*", http.NotFound)
 
+	// Empty health check endpoint to allow k8s and other orchestrators to check if the server is alive
+	// Useful to have a separate route for this for logging and metrics purposes
+	s.routeGet(m, "/-/health", func(w http.ResponseWriter, r *http.Request) {
+		w.WriteHeader(http.StatusOK)
+
+		if _, err := w.Write([]byte("OK")); err != nil {
+			s.log.Error("failed to write health check response", "error", err)
+		}
+	})
+
 	// All other requests return index.html
 	s.routeGet(m, "/*", s.index.HandleRequest)
 }

pkg/services/frontend/frontend_service_test.go

@@ -120,6 +120,16 @@ func TestFrontendService_Routes(t *testing.T) {
 
 		assert.Contains(t, recorder.Body.String(), "\nshrimp_count 1\n")
 	})
+
+	t.Run("should return health status correctly", func(t *testing.T) {
+		req := httptest.NewRequest("GET", "/-/health", nil)
+		recorder := httptest.NewRecorder()
+
+		mux.ServeHTTP(recorder, req)
+
+		assert.Equal(t, 200, recorder.Code)
+		assert.Equal(t, "OK", strings.TrimSpace(recorder.Body.String()))
+	})
 }
 
 func TestFrontendService_Middleware(t *testing.T) {