fix(multiplayer): gate API readiness on database

server/api/service_test.go

@@ -1487,6 +1487,59 @@ func TestMetricsEndpointExportsBoundedAPILatencyAndSkipsItsOwnScrape(t *testing.
 	}
 }
 
+func TestControlPlaneLivenessAndDatastoreReadinessAreIndependent(t *testing.T) {
+	ready := false
+	checks := 0
+	limiter, err := NewRateLimiter(1, time.Minute, 8)
+	if err != nil {
+		t.Fatal(err)
+	}
+	service := &Service{
+		RateLimiter: limiter,
+		Now:         func() time.Time { return time.Unix(1000, 0) },
+		ReadinessCheck: func(context.Context) error {
+			checks++
+			if !ready {
+				return errors.New("database unavailable")
+			}
+			return nil
+		},
+	}
+	handler := service.Handler()
+	status := func(method, path string) int {
+		recorder := httptest.NewRecorder()
+		handler.ServeHTTP(recorder, httptest.NewRequest(method, path, nil))
+		return recorder.Code
+	}
+	if got := status(http.MethodGet, "/healthz"); got != http.StatusOK {
+		t.Fatalf("liveness during datastore outage = %d", got)
+	}
+	if got := status(http.MethodGet, "/readyz"); got != http.StatusServiceUnavailable {
+		t.Fatalf("readiness during datastore outage = %d", got)
+	}
+	ready = true
+	if got := status(http.MethodGet, "/readyz"); got != http.StatusOK {
+		t.Fatalf("recovered readiness = %d", got)
+	}
+	if got := status(http.MethodGet, "/healthz"); got != http.StatusOK {
+		t.Fatalf("repeated probe was incorrectly rate limited: %d", got)
+	}
+	if checks != 2 {
+		t.Fatalf("readiness checks = %d", checks)
+	}
+	if got := status(http.MethodPost, "/readyz"); got != http.StatusMethodNotAllowed {
+		t.Fatalf("readiness mutation status = %d", got)
+	}
+}
+
+func TestControlPlaneReadinessFailsClosedWithoutCheck(t *testing.T) {
+	recorder := httptest.NewRecorder()
+	(&Service{}).Handler().ServeHTTP(recorder, httptest.NewRequest(http.MethodGet, "/readyz", nil))
+	if recorder.Code != http.StatusServiceUnavailable {
+		t.Fatalf("unconfigured readiness status = %d", recorder.Code)
+	}
+}
+
 func TestProbeAPIUsesServerEvidenceAndRejectsClientRTTField(t *testing.T) {
 	now := time.Unix(1000, 0).UTC()
 	sessions := domain.NewSessionStore()