func writeError()

in metrics.go [64:80]


func writeError(w io.Writer, message string, err error) {
	formattedMessage := fmt.Sprintf("%s: %v", message, err)

	log.Println(formattedMessage)

	errorMsg := errorResponse{
		Error: formattedMessage,
	}

	errorString, encodingError := json.Marshal(errorMsg)
	if encodingError != nil {
		encodingErrorMessage := fmt.Sprintf("Unable to encode response message %v", encodingError)
		log.Printf(encodingErrorMessage)
	}

	w.Write(errorString)
}