custom user-agent transport wrapper (#21483)

internal/http/transports.go

@@ -183,3 +183,23 @@ func (s ConnSettings) NewRemoteTargetHTTPTransport(insecure bool) func() *http.T
 		return tr
 	}
 }
+
+// uaTransport - User-Agent  transport
+type uaTransport struct {
+	ua string
+	rt http.RoundTripper
+}
+
+func (u *uaTransport) RoundTrip(req *http.Request) (*http.Response, error) {
+	req2 := req.Clone(req.Context())
+	req2.Header.Set("User-Agent", u.ua)
+	return u.rt.RoundTrip(req2)
+}
+
+// WithUserAgent wraps an existing transport with custom User-Agent
+func WithUserAgent(rt http.RoundTripper, getUA func() string) http.RoundTripper {
+	return &uaTransport{
+		ua: getUA(),
+		rt: rt,
+	}
+}