backend requirements onthe xustomer app

middlewares/requestid.go

@@ -0,0 +1,33 @@
+package middlewares
+
+import (
+	"crypto/rand"
+	"encoding/hex"
+
+	"github.com/gofiber/fiber/v2"
+)
+
+// RequestID echoes the caller's X-Request-Id on every response, errors
+// included, and mints one when the caller did not send it. The customer app
+// funnels all failures into a single retryable error state, so a support
+// conversation about "it failed" has nothing to correlate on unless the id the
+// client already holds comes back on the failing response too.
+//
+// Also stashed in c.Locals("requestid") so handlers can log it alongside the
+// real error they are hiding behind a customer-safe message.
+func RequestID() fiber.Handler {
+	return func(c *fiber.Ctx) error {
+		id := c.Get("X-Request-Id")
+		if id == "" {
+			b := make([]byte, 8)
+			if _, err := rand.Read(b); err == nil {
+				id = hex.EncodeToString(b)
+			}
+		}
+		if id != "" {
+			c.Locals("requestid", id)
+			c.Set("X-Request-Id", id)
+		}
+		return c.Next()
+	}
+}