Copypasta for easy versioning for your Go binaries

Golang-binary-versioning.md

Golang Binary Versioning Trick

To use, place the code in version_trick.go in your project. Don't forget to change the namespace to match yours to the actual name of your package.

In addition to version_trick.go, there's a makefile-snippet, that includes the secret sauce for making this trick work. Be sure to change the package name there as well.

Enjoy!

P.S. Special thanks to @meatballhat by way of @syscomet for showing me this trick!

Makefile

# be sure to change `modcloth-labs/mithril` to your namespace
REV_VAR := github.com/modcloth-labs/mithril.RevString
VERSION_VAR := github.com/modcloth-labs/mithril.VersionString
REPO_VERSION := $(shell git describe --always --dirty --tags)
REPO_REV := $(shell git rev-parse --sq HEAD)
GOBUILD_VERSION_ARGS := -ldflags "-X $(REV_VAR) $(REPO_REV) -X $(VERSION_VAR) $(REPO_VERSION)"

# then, change your `go install` statement from something like this:

go get -x $(TARGETS)
go install -x $(TARGETS)

# to something like this:

go get -x $(GOBUILD_VERSION_ARGS) $(TARGETS)
go install -x $(GOBUILD_VERSION_ARGS) $(TARGETS)

version_trick.go

package mithril

import (
        "fmt"
	"os"
	"path"
)

var (
	VersionString string
	RevString     string
	versionFlag = false
	revFlag = false
)

func init() {
	flag.BoolVar(&versionFlag, "version", false, "Print version and exit")
	flag.BoolVar(&revFlag, "rev", false, "Print git revision and exit")
}

func main() {
	flag.Parse() //you're probably already doing this somewhere

	if versionFlag {
		progName := path.Base(os.Args[0])
		if VersionString == "" {
			VersionString = "<unknown>"
		}
		fmt.Printf("%s %s\n", progName, VersionString)
		os.Exit(0)
	}

	if revFlag {
		if RevString == "" {
			RevString = "<unknown>"
		}
		fmt.Println(RevString)
		os.Exit(0)
	}
}