build.go

package main

import (
	"crypto/sha1"
	"flag"
	"fmt"
	"io"
	"log"
	"os"
	"os/exec"
	"path/filepath"
	"time"
)

func init() {
	altMain = notWindowsMain
}

var (
	buildWindows = flag.Bool("newwin", false, "force a make.bash of windows")

	buildArch = flag.String("arch", "amd64", "architecture to build")

	// Linux/OS X specific (use of HOME) because that's all that
	// Brad and Andrew use (and other gophers), and we're the only
	// ones who will be uploading this
	serviceAcctJSON = flag.String("service_account_json", filepath.Join(os.Getenv("HOME"), "keys/golang-org.service.json"),
		"Path to a Service Account JSON file from the golang-org project's Credentials screen")
)

func notWindowsMain() {
	build := flag.Bool("build", false, "build winstrap.exe")
	upload := flag.Bool("upload", false, "upload winstrap.exe to Google Cloud Storage (implies -build)")
	flag.Parse()
	if *upload {
		*build = true
	}
	if !*build {
		log.Printf("Not running on Windows and no flags specified.")
		flag.PrintDefaults()
		return
	}
	digest := buildWinstrap()
	if *upload {
		f, err := os.Open("winstrap.exe")
		check(err)
		defer f.Close()
		date := time.Now().Format("2006-01-02")
		fileName := fmt.Sprintf("winstrap-%s-%s.exe", date, digest[:7])
		check(Upload(fileName, f))
		log.Printf("uploaded %s", fileName)
		log.Printf("Paste this into Windows:\n   bitsadmin /transfer mydownloadjob  /download /priority normal https://storage.googleapis.com/winstrap/%s c:\\users\\wingopher\\Desktop\\winstrap.exe\n", fileName)
	}
}

// buildWinstrap builds a new winstrap.exe and returns its sha1
func buildWinstrap() string {
	log.Printf("building new winstrap.exe")

	goRoot := os.Getenv("GOROOT")
	if goRoot == "" {
		log.Fatal("no GOROOT set")
	}
	pkgWin := filepath.Join(goRoot, "pkg", "windows_"+*buildArch)
	if _, err := os.Stat(pkgWin); err != nil {
		if os.IsNotExist(err) {
			log.Printf("no %s directory, need to build windows cross-compiler", pkgWin)
			*buildWindows = true
		} else {
			log.Fatal(err)
		}
	}
	winEnv := append([]string{"CGO_ENABLED=0", "GOOS=windows", "GOARCH=" + *buildArch}, os.Environ()...)
	if *buildWindows {
		cmd := exec.Command(filepath.Join(goRoot, "src", "make.bash"))
		cmd.Stdout = os.Stdout
		cmd.Stderr = os.Stderr
		cmd.Env = winEnv
		cmd.Dir = filepath.Join(goRoot, "src")
		check(cmd.Run())
	}
	cmd := exec.Command("go", "build", "-o", "winstrap.exe")
	cmd.Env = winEnv
	out, err := cmd.CombinedOutput()
	if err != nil {
		log.Fatalf("Error building winstrap.exe %v: %s", err, out)
	}
	f, err := os.Open("winstrap.exe")
	check(err)
	defer f.Close()
	s1 := sha1.New()
	_, err = io.Copy(s1, f)
	check(err)
	digest := fmt.Sprintf("%x", s1.Sum(nil))
	log.Printf("built new winstrap.exe; %s", digest)
	return digest
}