Merge pull request #2865 from wey-gu/feat/usage-request-context

fix(gateway): preserve usage request context

backend/internal/server/middleware/client_request_id.go

@@ -11,6 +11,8 @@ import (
 	"go.uber.org/zap"
 )
 
+const clientRequestIDHeader = "X-Client-Request-ID"
+
 // ClientRequestID ensures every request has a unique client_request_id in request.Context().
 //
 // This is used by the Ops monitoring module for end-to-end request correlation.
@@ -21,12 +23,14 @@ func ClientRequestID() gin.HandlerFunc {
 			return
 		}
 
-		if v := c.Request.Context().Value(ctxkey.ClientRequestID); v != nil {
+		if v, _ := c.Request.Context().Value(ctxkey.ClientRequestID).(string); strings.TrimSpace(v) != "" {
+			c.Header(clientRequestIDHeader, strings.TrimSpace(v))
 			c.Next()
 			return
 		}
 
 		id := uuid.New().String()
+		c.Header(clientRequestIDHeader, id)
 		ctx := context.WithValue(c.Request.Context(), ctxkey.ClientRequestID, id)
 		requestLogger := logger.FromContext(ctx).With(zap.String("client_request_id", strings.TrimSpace(id)))
 		ctx = logger.IntoContext(ctx, requestLogger)

backend/internal/server/middleware/client_request_id_test.go

@@ -0,0 +1,50 @@
+package middleware
+
+import (
+	"context"
+	"net/http"
+	"net/http/httptest"
+	"testing"
+
+	"github.com/Wei-Shaw/sub2api/internal/pkg/ctxkey"
+	"github.com/gin-gonic/gin"
+	"github.com/stretchr/testify/require"
+)
+
+func TestClientRequestIDGeneratesAndExposesID(t *testing.T) {
+	gin.SetMode(gin.TestMode)
+	router := gin.New()
+	router.Use(ClientRequestID())
+	router.GET("/", func(c *gin.Context) {
+		value, _ := c.Request.Context().Value(ctxkey.ClientRequestID).(string)
+		c.String(http.StatusOK, value)
+	})
+
+	req := httptest.NewRequest(http.MethodGet, "/", nil)
+	w := httptest.NewRecorder()
+
+	router.ServeHTTP(w, req)
+
+	require.Equal(t, http.StatusOK, w.Code)
+	require.NotEmpty(t, w.Body.String())
+	require.Equal(t, w.Body.String(), w.Header().Get(clientRequestIDHeader))
+}
+
+func TestClientRequestIDPreservesExistingContextID(t *testing.T) {
+	gin.SetMode(gin.TestMode)
+	router := gin.New()
+	router.Use(ClientRequestID())
+	router.GET("/", func(c *gin.Context) {
+		value, _ := c.Request.Context().Value(ctxkey.ClientRequestID).(string)
+		c.String(http.StatusOK, value)
+	})
+
+	w := httptest.NewRecorder()
+	req := httptest.NewRequest(http.MethodGet, "/", nil)
+	req = req.WithContext(context.WithValue(req.Context(), ctxkey.ClientRequestID, "existing-client-request-id"))
+	router.ServeHTTP(w, req)
+
+	require.Equal(t, http.StatusOK, w.Code)
+	require.Equal(t, "existing-client-request-id", w.Body.String())
+	require.Equal(t, "existing-client-request-id", w.Header().Get(clientRequestIDHeader))
+}