Injecting Variables At Build Time

Full article: https://www.digitalocean.com/community/tutorials/using-ldflags-to-set-version-information-for-go-applications

TLDR:

Given some var in a file"

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package main

var (
	Version = "0.0.1"
	Commit  = "DEADBEEF"
)

func main() {
	fmt.Printf("Version: %s", Version)
	fmt.Printf("Commit: %s", Commit)
}

The following will overwrite them at build time (also works with go run)

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go build -ldflags="-X 'main.Version=1.0.0' -X 'main.Commit="BEEFDEAD"'"

If you are unsure of the full name of the variable you and run:

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go tool nm ./app | grep var_name   