Go / golang time.Now().UnixNano() convert to milliseconds?

Question

How can I get Unix time in Go in milliseconds?

I have the following function:

func makeTimestamp() int64 {
    return time.Now().UnixNano() % 1e6 / 1         


        

Answer 1

I think it's better to round the time to milliseconds before the division.

func makeTimestamp() int64 {
    return time.Now().Round(time.Millisecond).UnixNano() / (int64(time.Millisecond)/int64(time.Nanosecond))
}

Here is an example program:

package main

import (
        "fmt"
        "time"
)

func main() {
        fmt.Println(unixMilli(time.Unix(0, 123400000)))
        fmt.Println(unixMilli(time.Unix(0, 123500000)))
        m := makeTimestampMilli()
        fmt.Println(m)
        fmt.Println(time.Unix(m/1e3, (m%1e3)*int64(time.Millisecond)/int64(time.Nanosecond)))
}

func unixMilli(t time.Time) int64 {
        return t.Round(time.Millisecond).UnixNano() / (int64(time.Millisecond) / int64(time.Nanosecond))
}

func makeTimestampMilli() int64 {
        return unixMilli(time.Now())
}

The above program printed the result below on my machine:

123
124
1472313624305
2016-08-28 01:00:24.305 +0900 JST