Versioning with mage

magefile.go

// +build mage

package main


import (
	"encoding/json"
	"fmt"
	"io/ioutil"
	"os"
	"time"

	"github.com/Masterminds/semver"
	"github.com/magefile/mage/mg"
)

// Version mage versioning helper
type Version mg.Namespace

func check(e error) {
	if e != nil {
		panic(e)
	}
}

// Read Do not execute this command
func (v Version) Read() *semver.Version {
	if _, err := os.Stat(".buildver"); os.IsNotExist(err) {
		x, _ := semver.NewVersion("v0.0.0")
		err = v.write(*x)
		check(err)

		return x
	}

	var res map[string]interface{}

	b, err := ioutil.ReadFile(".buildver")
	check(err)

	err = json.Unmarshal(b, &res)
	check(err)

	version, err := semver.NewVersion(res["version"].(string))
	check(err)

	return version
}

func (v Version) write(vc semver.Version) error {
	b, err := json.Marshal(map[string]interface{}{
		"time":    time.Now(),
		"version": vc.String(),
	})

	err = ioutil.WriteFile(".buildver", b, 0644)
	return err
}

// Patch Increase match release
func (v Version) Patch() error {
	vc := v.Read()
	return v.write(vc.IncPatch())
}

// Minor Increase minor release
func (v Version) Minor() error {
	vc := v.Read()
	return v.write(vc.IncMinor())
}

// Major Increase major release
func (v Version) Major() error {
	vc := v.Read()
	return v.write(vc.IncMajor())
}

// Current Print the current version
func (v Version) Current() error {
	vc := v.Read()
	fmt.Println(vc.String())

	return nil
}