Dealing with Timezones and Unix Timestamp in Golang - go

Question

Given the following code:
https://go.dev/play/p/moLVHXIc4ba
It shows the next result:
now: 2009-11-10 23:00:00 +0000 UTC m=+0.000000001 | inLoc: 2009-11-10 18:00:00 -0500 -05unix | now: 1257894000 | inLoc: 1257894000
I don't get why when I call .Unix() to the date evaluated in Lima location, I get the same timestamp that original date in GMT.
I expect to get the timestamp corresponding to the original timestamp in GMT with 5 hours less as Lima has UTC -5.

Answer 1

I expect to get the timestamp corresponding to the original timestamp in GMT [UTC] with 5 hours less as Lima has UTC -5.
how can I get the timestamp with 5 hours less to pass to frontend?
You appear to be asking for this inLocTimestamp function. Five hours is 18,000 (5 * 60 * 60) seconds.
package main
import (
"fmt"
"time"
)
func inLocTimestamp(inLoc time.Time) int64 {
_, offset := inLoc.Zone()
ts := inLoc.Add(time.Duration(offset) * time.Second)
return ts.Unix()
}
func inLocTimestampMilli(inLoc time.Time) int64 {
_, offset := inLoc.Zone()
ts := inLoc.Add(time.Duration(offset) * time.Second)
return ts.UnixMilli()
}
func main() {
loc, _ := time.LoadLocation("America/Lima")
now := time.Now().Round(0)
inLoc := now.In(loc)
fmt.Printf("time | now: %v | inLoc: %v\n", now, inLoc)
fmt.Printf("unix | now: %v | inLoc: %v\n", now.Unix(), inLoc.Unix())
fmt.Printf("timestamp | now: %v | inLoc: %v\n", now.Unix(), inLocTimestamp(inLoc))
fmt.Printf("difference | inLoc: timestamp - unix = %v\n", inLocTimestamp(inLoc)-inLoc.Unix())
}
https://go.dev/play/p/IyzA4qZLLuS
time | now: 2009-11-10 23:00:00 +0000 UTC | inLoc: 2009-11-10 18:00:00 -0500 -05
unix | now: 1257894000 | inLoc: 1257894000
timestamp | now: 1257894000 | inLoc: 1257876000
difference | inLoc: timestamp - unix = -18000