Makefile for building version strings from Git data and including that version numbers into go programs

main.go

package main

import (
	// ...
)

var version = "dev"

func main() {
	// ...
}

Makefile

TAG_COMMIT := $(shell git rev-list --abbrev-commit --tags --max-count=1)
TAG := $(shell git describe --abbrev=0 --tags ${TAG_COMMIT} 2>/dev/null || true)
COMMIT := $(shell git rev-parse --short HEAD)
DATE := $(shell git log -1 --format=%cd --date=format:"%Y%m%d")
VERSION := $(TAG:v%=%)
ifneq ($(COMMIT), $(TAG_COMMIT))
	VERSION := $(VERSION)-next-$(COMMIT)-$(DATE)
endif
ifeq $(VERSION,)
	VERSION := $(COMMIT)-$(DATA)
endif
ifneq ($(shell git status --porcelain),)
	VERSION := $(VERSION)-dirty
endif

FLAGS := -ldflags "-X main.version=$(VERSION)"

build:
	go build $(FLAGS) -o projectname-$(VERSION) main.go

run:
	go run $(FLAGS) main.go

install:
	go install $(FLAGS)

And line 10 should be changed to

	VERSION := $(COMMIT)-$(DATE)

("DATE", not "DATA")

Also, when run on a repo that truly has no tags, $(COMMIT)-$(DATE) is not what VERSION gets set to. It gets set to -next-$(COMMIT)-$(DATE).

To do as designed in the blog post, lines 9&10 should be changed to

ifeq ($(TAG_COMMIT),)
	VERSION := $(COMMIT)-$(DATE)