git-version.go

Use git tags to add semver to your go package.

Goal: Either use an exact version like v1.0.0
      or translate the git version like v1.0.0-4-g0000000
      to a semver like v1.0.1-pre4+g0000000

      Fail gracefully when git repo isn't available.

Demo

go run git.rootprojects.org/root/go-gitver

Usage

See examples/basic

1. Create a tools package in your project
2. Guard it against regular builds with // build +tools
3. Include _ "git.rootprojects.org/root/go-gitver" in the imports
4. Declare var GitRev, GitVersion, GitTimestamp string in your package main
5. Include //go:generate go run -mod=vendor git.rootprojects.org/root/go-gitver as well

tools/tools.go:

// build +tools

// This is a dummy package for build tooling
package tools

import (
  _ "git.rootprojects.org/root/go-gitver"
)

main.go:

//go:generate go run -mod=vendor git.rootprojects.org/root/go-gitver

package main

import "fmt"

var (
  GitRev = "0000000"
  GitVersion = "v0.0.0-pre0+g0000000"
  GitTimestamp = "0000-00-00T00:00:00+0000"
)

func main() {
  fmt.Println(GitRev)
  fmt.Println(GitVersion)
  fmt.Println(GitTimestamp)
}

Behind the curtain

These are the commands that are used under the hood to produce the versions.

Shows the git tag + description. Assumes that you're using the semver format v1.0.0 for your base tags.

git describe --tags --dirty --always
# v1.0.0
# v1.0.0-1-g0000000
# v1.0.0-dirty

Show the commit date (when the commit made it into the current tree). Internally we use the current date when the working tree is dirty.

git show v1.0.0-1-g0000000 --format=%cd --date=format:%Y-%m-%dT%H:%M:%SZ%z --no-patch
# 2010-01-01T20:30:00Z-0600
# fatal: ambiguous argument 'v1.0.0-1-g0000000-dirty': unknown revision or path not in the working tree.

Shows the most recent commit.

git rev-parse HEAD
# 0000000000000000000000000000000000000000