feat: 完善服务监控与下游重投

gateway/internal/metrics/metrics_test.go

@@ -0,0 +1,29 @@
+package metrics
+
+import (
+	"context"
+	"net/http"
+	"net/http/httptest"
+	"strings"
+	"testing"
+	"time"
+)
+
+func TestMetricsHandlerExportsOnlyAggregateGatewayState(t *testing.T) {
+	ObserveSubmit(true, 20*time.Millisecond)
+	request := httptest.NewRequest(http.MethodGet, "/metrics", nil)
+	response := httptest.NewRecorder()
+	Handler(func(context.Context) Snapshot {
+		return Snapshot{UpstreamDesired: 2, UpstreamConnected: 1, DownstreamConnected: 3, SubmitWorkerUp: true, QueueAvailable: true, QueuePending: 4, QueueLag: 5, QueueOldestAgeSeconds: 12}
+	}).ServeHTTP(response, request)
+
+	body := response.Body.String()
+	if response.Code != http.StatusOK || !strings.Contains(body, "cmpp_gateway_submit_queue_pending 4") || !strings.Contains(body, "cmpp_gateway_upstream_connections{state=\"connected\"} 1") {
+		t.Fatalf("unexpected metrics response: code=%d body=%s", response.Code, body)
+	}
+	for _, forbidden := range []string{"phone_number", "message_id", "channel_id"} {
+		if strings.Contains(body, forbidden) {
+			t.Fatalf("metrics expose forbidden label %q", forbidden)
+		}
+	}
+}