sg.go

type Logger struct {
    file *os.File
}

func (l *Logger) Log(message string) {
    _, _ = l.file.WriteString(message + "\n")
}

var logger *Logger

func GetLogger() *Logger {
    if logger == nil {
        file, _ := os.OpenFile("log.txt", os.O_CREATE|os.O_APPEND|os.O_WRONLY, 0644)
        logger = &Logger{file: file}
    }
    return logger
}