xbps-src templating in go

xtemplate.go

package main

import "fmt"
import "os"
import "flag"
import "strconv"
import "strings"
import "text/template"
import "crypto/sha256"
import "encoding/hex"

func usage() {
	fmt.Printf("Usage: %s %s\n",
		os.Args[0],
		"opts")
	os.Exit(1)
}

func setflag(s interface{}, e string, r bool) {
	switch s := s.(type) {
	case string:
		setstring(s, e, r)
	case int:
		setint(s, e, r)
	default:
		fmt.Printf("%s\n", s)
	}
}

func setstring(s string, e string, r bool) {
	var env string
	env = "XTEMPLATE_" + strings.ToUpper(e)
	
	if s == "" {
		if os.Getenv(env) != "" {
			s = os.Getenv(strings.ToUpper(env))
		} else {
			if r == true {
				fmt.Printf("%s is required\n", e)
				os.Exit(1)
			}
		}
	}
}

func setint(s int, e string, r bool) {
	var env string
	env = "XTEMPLATE_" + strings.ToUpper(e)
	
	if s == 0 {
		if os.Getenv(env) != "" {
			s, _ = strconv.Atoi(os.Getenv(env))
		} else {
			if r == true {
				fmt.Printf("%s is required\n", e)
				os.Exit(1)
			}
		}			
	}
}

func template_file() string{
	return `# Template file for '{{.pkgname}}'

pkgname="{{.pkgname}}"
version="{{.version}}"
revision="{{.revision}}"
short_desc="{{.shortdesc}}"
maintainer="{{.maintainer}}"
license="{{.license}}"
homepage="{{.homepage}}"
distfiles="{{.distfiles}}"
checksum="{{.checksum}}"
{{if .buildstyle}}build_style={{.buildstyle}}
{{end}}
`

}

func ret(opts map[string]interface{}) {
	t := template.Must(template.New("temp").Parse(template_file()))
	t.Execute(os.Stdout, opts)
}

func args() {
	usageFlag := flag.Bool("usage", false, "return help")
	homepageFlag := flag.String("homepage", "", "homepage project")
	licenseFlag := flag.String("license", "", "project licence")
	maintainerFlag := flag.String("maintainer", "", "template maintainer")
	pkgnameFlag := flag.String("pkgname", "", "package name")
	revisionFlag := flag.Int("revision", 1, "template revision")
	shortdescFlag := flag.String("shortdesc", "", "short description of the project")
	versionFlag := flag.String("version", "", "project version")
	buildstyleFlag := flag.String("buildstyle", "", "build style helper")
	distfilesFlag := flag.String("distfiles", "", "package target")
	checksumFlag := flag.String("checksum", "", "package checksum")
	
	//outputFlag := flag.String("output", "", "output")
	flag.Parse()
	
	if *usageFlag == true {
		usage()
	}

	setflag(*homepageFlag, "homepage", true)
	setflag(*licenseFlag, "license", true)
	setflag(*maintainerFlag, "maintainer", true)
	setflag(*pkgnameFlag, "pkgname", true)
	setflag(*revisionFlag, "revision", true)
	setflag(*shortdescFlag, "shortdesc", true)
	setflag(*versionFlag, "version", true)
	setflag(*buildstyleFlag, "buildstyle", false)

	if *distfilesFlag != "" && *checksumFlag == "" {
		fmt.Println("getfile")
		sha := sha256.Sum256([]byte(*distfilesFlag))
		shas := sha[:]
		enc := hex.EncodeToString(shas)
		fmt.Println(enc)
		*checksumFlag = enc
	}

	var opts = map[string]interface{} {
		"homepage": *homepageFlag,
		"license": *licenseFlag,
		"maintainer": *maintainerFlag,
		"pkgname": *pkgnameFlag,
		"revision": *revisionFlag,
		"shortdesc": *shortdescFlag,
		"version": *versionFlag,
		"buildstyle": *buildstyleFlag,
		"distfiles": *distfilesFlag,
		"checksum": *checksumFlag,
	}

	ret(opts)
}


func main() {
	args()
}