How to properly use build tags?

Question

I need to be able to build different versions of a go application; a \'debug\' version and a normal version.

This is easy to do; I simply have a const DEBUG, that contro

Answer 1

You could use compile time constants for that: If you compile your program with

go build -ldflags '-X main.DEBUG=YES' test.go

the variable DEBUG from package main will be set to the string "YES". Otherwise it keeps its declared contents.

package main

import (
    "fmt"
)

var DEBUG = "NO"

func main() {
    fmt.Printf("DEBUG is %q\n", DEBUG)
}

---

Edit: since Go 1.6(?) the switch is -X main.DEBUG=YES, before that it was -X main.DEBUG YES (without the =). Thanks to a comment from @poorva.