blob: dd1922322b4e6630728594ea5bcea096ef271c9e [file] [log] [blame]
// Copyright 2018 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
//go:build go1.13
// +build go1.13
// The genv command generates version-specific go command source files.
package main
import (
"bytes"
"encoding/json"
"errors"
"fmt"
"html/template"
"io/ioutil"
"os"
"os/exec"
"path/filepath"
"regexp"
"strings"
"time"
)
func usage() {
fmt.Fprintln(os.Stderr, "usage: genv <version>...")
os.Exit(2)
}
func main() {
if len(os.Args) == 1 {
usage()
}
dlRoot, err := golangOrgDlRoot()
if err != nil {
failf("golangOrgDlRoot: %v", err)
}
for _, version := range os.Args[1:] {
if !strings.HasPrefix(version, "go") {
failf("version names should have the 'go' prefix")
}
var buf bytes.Buffer
if err := mainTmpl.Execute(&buf, struct {
Year int
Version string // "go1.5.3rc2"
VersionNoPatch string // "go1.5"
CapitalSpaceVersion string // "Go 1.5"
DocHost string // "golang.org" or "tip.golang.org" for rc/beta
}{
Year: time.Now().Year(),
Version: version,
VersionNoPatch: versionNoPatch(version),
DocHost: docHost(version),
CapitalSpaceVersion: strings.Replace(version, "go", "Go ", 1),
}); err != nil {
failf("mainTmpl.execute: %v", err)
}
path := filepath.Join(dlRoot, version, "main.go")
if err := os.MkdirAll(filepath.Dir(path), 0755); err != nil {
failf("%v", err)
}
if err := ioutil.WriteFile(path, buf.Bytes(), 0666); err != nil {
failf("ioutil.WriteFile: %v", err)
}
fmt.Println("Wrote", path)
if err := exec.Command("gofmt", "-w", path).Run(); err != nil {
failf("could not gofmt file %q: %v", path, err)
}
}
}
func docHost(ver string) string {
if strings.Contains(ver, "rc") || strings.Contains(ver, "beta") {
return "tip.golang.org"
}
return "golang.org"
}
func versionNoPatch(ver string) string {
rx := regexp.MustCompile(`^(go\d+\.\d+)($|[\.]?\d*)($|rc|beta|\.)`)
m := rx.FindStringSubmatch(ver)
if m == nil {
failf("unrecognized version %q", ver)
}
if m[2] != "" {
return "devel/release.html#" + m[1] + ".minor"
}
return m[1]
}
func failf(format string, args ...interface{}) {
if len(format) == 0 || format[len(format)-1] != '\n' {
format += "\n"
}
fmt.Fprintf(os.Stderr, format, args...)
os.Exit(1)
}
var mainTmpl = template.Must(template.New("main").Parse(`// Copyright {{.Year}} The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// The {{.Version}} command runs the go command from {{.CapitalSpaceVersion}}.
//
// To install, run:
//
// $ go get golang.org/dl/{{.Version}}
// $ {{.Version}} download
//
// And then use the {{.Version}} command as if it were your normal go
// command.
//
// See the release notes at https://{{.DocHost}}/doc/{{.VersionNoPatch}}
//
// File bugs at https://golang.org/issues/new
package main
import "golang.org/dl/internal/version"
func main() {
version.Run("{{.Version}}")
}
`))
// golangOrgDlRoot determines the directory corresponding to the root
// of module golang.org/dl by invoking 'go list -m' in module mode.
// It must be called with a working directory that is contained
// by the golang.org/dl module, otherwise it returns an error.
func golangOrgDlRoot() (string, error) {
cmd := exec.Command("go", "list", "-m", "-json")
cmd.Env = append(os.Environ(), "GO111MODULE=on")
out, err := cmd.Output()
if ee := (*exec.ExitError)(nil); errors.As(err, &ee) {
return "", fmt.Errorf("go command exited unsuccessfully: %v\n%s", ee.ProcessState.String(), ee.Stderr)
} else if err != nil {
return "", err
}
var mod struct {
Path string // Module path.
Dir string // Directory holding files for this module.
}
err = json.Unmarshal(out, &mod)
if err != nil {
return "", err
}
if mod.Path != "golang.org/dl" {
return "", fmt.Errorf("working directory must be in module golang.org/dl, but 'go list -m' reports it's currently in module %s", mod.Path)
}
return mod.Dir, nil
}