How to get complete response for Groovy RestClient failed response

Add custom failed response handler:

        restClient = new RESTClient("http://${Server}")
        restClient.handler.failure = { resp, data ->
            resp.setData(data)
            String headers = ""
            resp.headers.each {
                headers = headers+"${it.name} : ${it.value}\n"
            }
            throw new HttpResponseException(resp.getStatus(),"HTTP call failed. Status code: ${resp.getStatus()}\n${headers}\n"+
                                            "Response: "+(resp as HttpResponseDecorator).getData())
        }