谁将日期和时间写入日志文件？

Question

I wrote this little function to log into file

func logMessage(message string) {
    file, err := os.OpenFile("my.log", O_CREATE|O_RDWR|O_APPEND, 0)
    if err != nil {
        panic(err)
    }
    defer file.Close()
    log.SetOutput(file)
    log.Println(message)
}

But what I do not understand is why

logMessage("foo")
logMessage("bar")

write this content into file:

2017/03/21 03:34:42 foo
2017/03/21 03:34:42 bar

Can I write without YYYY/MM/DD HH:II:SS?

Answer 1

Create a logger instance with its flags set to 0:

log.New(dest, "", 0)

References:

• https://golang.org/pkg/log/#pkg-constants

Demo: https://play.golang.org/p/ssVaeS9YAu