if err != nil {
		return nil, err
	}
	return setupConfigdumpEnvoyConfigWriter(debug, out)
}

func readFile(filename string) ([]byte, error) {
	file := os.Stdin
	if filename != "-" {
		var err error
		file, err = os.Open(filename)
		if err != nil {
			return nil, err
		}
	}
	defer func() {
		if err := file.Close(); err != nil {