How to convert ISO 8601 time in golang?

If you're looking for a simple, but not perfect solution consider using time.RFC3339 constant. But also know that there are differences between ISO8601 which are too complex for this answer.

See https://ijmacd.github.io/rfc3339-iso8601/ for differences and also has a handy test file generator to show differences. There is also a good discussion on SO here What's the difference between ISO 8601 and RFC 3339 Date Formats?

package main

import (
    "time"
    "fmt"
)

func main(){
    fmt.Println(time.Now().Format(time.RFC3339))
}

golang Time.Format

I had the following spec:

YYYY-MM-DDThh:mm:ss.sssZ

with the final Z being explicitly present in the examples.

Here's how I dealt with it:

• first I found the time.RFCxxx that was the closest to my target
• I copied its value
• I fiddled with it until I found the expected result

which is

2006-01-02T15:04:05.999Z

ISO8601 allows for variable levels of granularity. You can have just a year, year+month, year+month+day, add a time portion, and optionally have a timezone portion. Go's built-in time parsing, however, requires you to know ahead-of-time which parts will be included.

The github.com/btubbs/datetime library provides a more flexible parser that can handle all the commonly used ISO8601 formats. See https://github.com/btubbs/datetime

Disclosure: I wrote that library.

package main

import (
    "fmt"
    "time"
)

func main() {
    fmt.Println(time.Now().UTC().Format("2006-01-02T15:04:05-0700"))
}