+ var message string
+ var errDoc httpserver.ErrorResponse
+ if err := json.Unmarshal(body, &errDoc); err == nil {
+ message = strings.Join(errDoc.Errors, "; ")
+ } else {
+ message = fmt.Sprintf("%q", body)
+ }
+ err = fmt.Errorf("server did not provide a tunnel: %s (HTTP %d)", message, resp.StatusCode)