Build Time Variables

While not entirely new learning, I spent time today working on variable injection using ldflags with go build - the Gopher Guide folks have an article on Digital Ocean to learn about using ldflags for setting version information

Until today I always thought variable injection worked for variables defined in a Go program’s main package. In needing to inject a version string held by an exported Version variable in a cmd package, I learned the way to reference the variable within the ldflags is to use the full import path of the cmd package.

go build -- ldflags '-X github.com/example/cmd.Version=X.Y.Z'

For context, the ldflags mentioned in this post are part of a goreleaser build pipeline for setting the binary version to the value of a git tag.