Get the full name of your local time zone (OS setting)

Works on windows, linux and macos

Why?

built-in functionality sometimes won't suffice:

zone, _ := time.Now().Zone() // my time zone
fmt.Println(zone) // e.g. "CEST"

loc, err := time.LoadLocation(zone)
if err != nil {
    // the program panics here:
    panic("fail: could not load location from zone")
}

// unreachable:
fmt.Println("success: location loaded from zone")

localizing a date with obtained loc will cause an error because it's not in the IANA format.

panic: time: missing Location in call to Date

While tzlocal gives the correct IANA name

tzname, _ := tzlocal.RuntimeTZ() // assuming error is handled
fmt.Printf("Actual IANA name: %v\n", tzname) // Prints "Actual IANA name: Europe/Paris"

---

Package Usage

go get github.com/thlib/go-timezone-local/tzlocal

See it in action:

Open your project folder
Create a file main.go

package main

import (
    "fmt"
    "time"

    "github.com/thlib/go-timezone-local/tzlocal"
)

func main() {
    tzname, err := tzlocal.RuntimeTZ()
    fmt.Println(tzname, err)

    // example:
    // tzname = "Europe/Berlin"

    // now you can use tzname to properly set up a location:
    loc, _ := time.LoadLocation(tzname)

    d0 := time.Date(2021, 10, 30, 20, 0, 0, 0, loc) // DST active:
    fmt.Println(d0)
    // 2021-10-30 20:00:00 +0200 CEST

    d1 := d0.AddDate(0, 0, 1) // add one day, now DST is inactive:
    fmt.Println(d1)
    // 2021-10-31 20:00:00 +0100 CET
}

Run the following commands:

go mod init example.com/yourpackage
go mod vendor
go run main.go

It should print the go runtime timezone.

For contributors to update the list of time zones on windows

Clone github.com/thlib/go-timezone-local
Change directory to go-timezone-local

cd go-timezone-local
go generate ./...

Credits

All credit goes to the various contributors, colm.anseo and MrFuppes for providing the following answers:

• https://stackoverflow.com/a/68938947/175071
• https://stackoverflow.com/a/68966317/175071