go-watchdog/tools/version/version.go

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2019-06-12 07:45:28 +00:00
// +build tools
package main
import (
"bytes"
"fmt"
"go/format"
"os"
"os/exec"
"regexp"
"strconv"
"strings"
"text/template"
"time"
)
var exactVer *regexp.Regexp
var gitVer *regexp.Regexp
var verFile = "generated-version.go"
func init() {
// exactly vX.Y.Z (go-compatible semver)
exactVer = regexp.MustCompile(`^v\d+\.\d+\.\d+$`)
// vX.Y.Z-n-g0000000 git post-release, semver prerelease
gitVer = regexp.MustCompile(`^(v\d+\.\d+)\.(\d+)-(\d+)-g`)
}
// 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
// Don't fail when git repo isn't available.
func main() {
desc := gitDesc()
rev := gitRev()
ver := semVer(desc)
ts := time.Now().Format(time.RFC3339)
v := struct {
Timestamp string
Version string
GitRev string
}{
Timestamp: ts,
Version: ver,
GitRev: rev,
}
// Create or overwrite the go file from template
var buf bytes.Buffer
if err := versionTpl.Execute(&buf, v); nil != err {
panic(err)
}
// Format
src, err := format.Source(buf.Bytes())
if nil != err {
panic(err)
}
// Write to disk (in the Current Working Directory)
f, err := os.Create(verFile)
if nil != err {
panic(err)
}
if _, err := f.Write(src); nil != err {
panic(err)
}
if err := f.Close(); nil != err {
panic(err)
}
}
func gitDesc() string {
args := strings.Split("git describe --tags --dirty --always", " ")
cmd := exec.Command(args[0], args[1:]...)
out, err := cmd.CombinedOutput()
if nil != err {
// Don't panic, just carry on
out = []byte("v0.0.0-0-g0000000")
}
return strings.TrimSpace(string(out))
}
func gitRev() string {
args := strings.Split("git rev-parse HEAD", " ")
cmd := exec.Command(args[0], args[1:]...)
out, err := cmd.CombinedOutput()
if nil != err {
// Don't panic, just carry on
out = []byte("00000000000000000")
}
return strings.TrimSpace(string(out))
}
func semVer(desc string) string {
var ver string
if exactVer.MatchString(desc) {
// v1.0.0
ver = desc
} else if gitVer.MatchString(desc) {
// ((v1.0).(0)-(1))
vers := gitVer.FindStringSubmatch(desc)
patch, err := strconv.Atoi(vers[2])
if nil != err {
panic(err)
}
// v1.0.1-pre1
ver = fmt.Sprintf("%s.%d-pre%s", vers[1], patch+1, vers[3])
}
return ver
}
var versionTpl = template.Must(template.New("").Parse(`// Code generated by go generate; DO NOT EDIT.
package main
func init() {
Timestamp = "{{ .Timestamp }}"
Version = "{{ .Version }}"
GitRev = "{{ .GitRev }}"
}
`))