code: func panicHandler(handler http.Handler) http.Handler {
  	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
  		defer func() {
  			if err := recover(); err != nil {
  				log.Panic(fmt.Sprintf("%v", err))
  			}
  		}()
  		handler.ServeHTTP(w, r)
  	})
  }
docs: // panicHandler add an HTTP handler to web app. The handler recover the happening
  // panic. logrus.Panic transmits panic message to pre-config log hooks, which is
  // defined in config.yml.