feat: add health and readiness endpoints

README.md

@@ -26,6 +26,14 @@ When trusted proxies are configured, forwarded headers are honored only for trus
 Response:
 - JSON object: `status`, `message`, optional `client`
 
+### `GET /healthz`
+
+Unauthenticated liveness endpoint for orchestration probes.
+
+### `GET /readyz`
+
+Unauthenticated readiness endpoint for orchestration probes.
+
 ## Config
 
 Use one YAML file.

internal/httpapi/handler.go

@@ -34,9 +34,23 @@ func New(cfg *appconfig.Config, resolver *ipresolver.Resolver, updater *provider
 }
 
 func (h *Handler) Register(mux *http.ServeMux) {
+	mux.HandleFunc("GET /healthz", h.Healthz)
+	mux.HandleFunc("GET /readyz", h.Readyz)
 	mux.HandleFunc("POST /update", h.Update)
 }
 
+func (h *Handler) Healthz(w http.ResponseWriter, _ *http.Request) {
+	writeJSON(w, http.StatusOK, response{Status: "ok", Message: "alive"})
+}
+
+func (h *Handler) Readyz(w http.ResponseWriter, _ *http.Request) {
+	if h.cfg == nil || h.resolver == nil || h.updater == nil {
+		writeJSON(w, http.StatusServiceUnavailable, response{Status: "error", Message: "not ready"})
+		return
+	}
+	writeJSON(w, http.StatusOK, response{Status: "ok", Message: "ready"})
+}
+
 func (h *Handler) Update(w http.ResponseWriter, r *http.Request) {
 	token, err := bearerToken(r.Header.Get("Authorization"))
 	if err != nil {

internal/httpapi/handler_test.go

@@ -64,3 +64,56 @@ func TestWriteJSON(t *testing.T) {
 		t.Fatalf("unmarshal: %v", err)
 	}
 }
+
+func TestHealthzRoute(t *testing.T) {
+	cfg := testConfig()
+	resolver, _ := ipresolver.New(nil)
+	h := New(cfg, resolver, provider.NewUpdater())
+	mux := http.NewServeMux()
+	h.Register(mux)
+
+	r := httptest.NewRequest(http.MethodGet, "/healthz", nil)
+	w := httptest.NewRecorder()
+	mux.ServeHTTP(w, r)
+
+	if w.Code != http.StatusOK {
+		t.Fatalf("unexpected code: %d", w.Code)
+	}
+	var body response
+	if err := json.Unmarshal(w.Body.Bytes(), &body); err != nil {
+		t.Fatalf("unmarshal: %v", err)
+	}
+	if body.Status != "ok" || body.Message != "alive" {
+		t.Fatalf("unexpected body: %+v", body)
+	}
+}
+
+func TestReadyzRoute(t *testing.T) {
+	cfg := testConfig()
+	resolver, _ := ipresolver.New(nil)
+	h := New(cfg, resolver, provider.NewUpdater())
+	mux := http.NewServeMux()
+	h.Register(mux)
+
+	r := httptest.NewRequest(http.MethodGet, "/readyz", nil)
+	w := httptest.NewRecorder()
+	mux.ServeHTTP(w, r)
+
+	if w.Code != http.StatusOK {
+		t.Fatalf("unexpected code: %d", w.Code)
+	}
+}
+
+func TestReadyzNotReady(t *testing.T) {
+	h := New(nil, nil, nil)
+	mux := http.NewServeMux()
+	h.Register(mux)
+
+	r := httptest.NewRequest(http.MethodGet, "/readyz", nil)
+	w := httptest.NewRecorder()
+	mux.ServeHTTP(w, r)
+
+	if w.Code != http.StatusServiceUnavailable {
+		t.Fatalf("unexpected code: %d", w.Code)
+	}
+}