Fix build.go

build.go

@@ -1,9 +1,17 @@
+// Description
+//
+// This program aims to make building Go programs for end users easier by just
+// calling it with `go run`, without having to setup a GOPATH.
+//
+// This program needs Go >= 1.11. It'll use Go modules for compilation. It
+// builds the package configured as Main in the Config struct.
+
 // BSD 2-Clause License
 //
 // Copyright (c) 2016-2018, Alexander Neumann <alexander@bumpern.de>
 // All rights reserved.
 //
-// This file has been copied from the repository at:
+// This file has been derived from the repository at:
 // https://github.com/fd0/build-go
 //
 // Redistribution and use in source and binary forms, with or without
@@ -37,7 +45,6 @@ import (
 	"io/ioutil"
 	"os"
 	"os/exec"
-	"path"
 	"path/filepath"
 	"runtime"
 	"strconv"
@@ -46,163 +53,31 @@ import (
 
 // config contains the configuration for the program to build.
 var config = Config{
-	Name:      "rest-server",                                   // name of the program executable and directory
+	Name:       "rest-server",                                   // name of the program executable and directory
-	Namespace: "github.com/restic/rest-server",                 // subdir of GOPATH, e.g. "github.com/foo/bar"
+	Namespace:  "github.com/restic/rest-server",                 // subdir of GOPATH, e.g. "github.com/foo/bar"
-	Main:      "github.com/restic/rest-server/cmd/rest-server", // package name for the main package
+	Main:       "github.com/restic/rest-server/cmd/rest-server", // package name for the main package
-	Tests: []string{ // tests to run
+	Tests:      []string{"./..."},                               // tests to run
-		"github.com/restic/rest-server",
+	MinVersion: GoVersion{Major: 1, Minor: 11, Patch: 0},        // minimum Go version supported
-		"github.com/restic/rest-server/cmd/rest-server",
-	},
-	MinVersion: GoVersion{Major: 1, Minor: 7, Patch: 0}, // minimum Go version supported
 }
 
 // Config configures the build.
 type Config struct {
-	Name       string
+	Name             string
-	Namespace  string
+	Namespace        string
-	Main       string
+	Main             string
-	Tests      []string
+	DefaultBuildTags []string
-	MinVersion GoVersion
+	Tests            []string
+	MinVersion       GoVersion
 }
 
 var (
-	verbose    bool
+	verbose   bool
-	keepGopath bool
+	runTests  bool
-	runTests   bool
+	enableCGO bool
-	enableCGO  bool
+	enablePIE bool
+	goVersion = ParseGoVersion(runtime.Version())
 )
 
-// specialDir returns true if the file begins with a special character ('.' or '_').
-func specialDir(name string) bool {
-	if name == "." {
-		return false
-	}
-
-	base := filepath.Base(name)
-	if base == "vendor" || base[0] == '_' || base[0] == '.' {
-		return true
-	}
-
-	return false
-}
-
-// excludePath returns true if the file should not be copied to the new GOPATH.
-func excludePath(name string) bool {
-	ext := path.Ext(name)
-	if ext == ".go" || ext == ".s" || ext == ".h" {
-		return false
-	}
-
-	parentDir := filepath.Base(filepath.Dir(name))
-	if parentDir == "testdata" {
-		return false
-	}
-
-	return true
-}
-
-// updateGopath builds a valid GOPATH at dst, with all Go files in src/ copied
-// to dst/prefix/, so calling
-//
-//   updateGopath("/tmp/gopath", "/home/u/restic", "github.com/restic/restic")
-//
-// with "/home/u/restic" containing the file "foo.go" yields the following tree
-// at "/tmp/gopath":
-//
-//   /tmp/gopath
-//   └── src
-//       └── github.com
-//           └── restic
-//               └── restic
-//                   └── foo.go
-func updateGopath(dst, src, prefix string) error {
-	verbosePrintf("copy contents of %v to %v\n", src, filepath.Join(dst, prefix))
-	return filepath.Walk(src, func(name string, fi os.FileInfo, err error) error {
-		if name == src {
-			return err
-		}
-
-		if specialDir(name) {
-			if fi.IsDir() {
-				return filepath.SkipDir
-			}
-
-			return nil
-		}
-
-		if err != nil {
-			return err
-		}
-
-		if fi.IsDir() {
-			return nil
-		}
-
-		if excludePath(name) {
-			return nil
-		}
-
-		intermediatePath, err := filepath.Rel(src, name)
-		if err != nil {
-			return err
-		}
-
-		fileSrc := filepath.Join(src, intermediatePath)
-		fileDst := filepath.Join(dst, "src", prefix, intermediatePath)
-
-		return copyFile(fileDst, fileSrc)
-	})
-}
-
-func directoryExists(dirname string) bool {
-	stat, err := os.Stat(dirname)
-	if err != nil && os.IsNotExist(err) {
-		return false
-	}
-
-	return stat.IsDir()
-}
-
-// copyFile creates dst from src, preserving file attributes and timestamps.
-func copyFile(dst, src string) error {
-	fi, err := os.Stat(src)
-	if err != nil {
-		return err
-	}
-
-	fsrc, err := os.Open(src)
-	if err != nil {
-		return err
-	}
-
-	if err = os.MkdirAll(filepath.Dir(dst), 0755); err != nil {
-		return err
-	}
-
-	fdst, err := os.Create(dst)
-	if err != nil {
-		return err
-	}
-
-	if _, err = io.Copy(fdst, fsrc); err != nil {
-		return err
-	}
-
-	if err = fsrc.Close(); err != nil {
-		return err
-	}
-
-	if err = fdst.Close(); err != nil {
-		return err
-	}
-
-	if err = os.Chmod(dst, fi.Mode()); err != nil {
-		return err
-	}
-
-	return os.Chtimes(dst, fi.ModTime(), fi.ModTime())
-}
-
 // die prints the message with fmt.Fprintf() to stderr and exits with an error
 // code.
 func die(message string, args ...interface{}) {
@@ -216,12 +91,13 @@ func showUsage(output io.Writer) {
 	fmt.Fprintf(output, "OPTIONS:\n")
 	fmt.Fprintf(output, "  -v     --verbose       output more messages\n")
 	fmt.Fprintf(output, "  -t     --tags          specify additional build tags\n")
-	fmt.Fprintf(output, "  -k     --keep-gopath   do not remove the GOPATH after build\n")
 	fmt.Fprintf(output, "  -T     --test          run tests\n")
 	fmt.Fprintf(output, "  -o     --output        set output file name\n")
 	fmt.Fprintf(output, "         --enable-cgo    use CGO to link against libc\n")
+	fmt.Fprintf(output, "         --enable-pie    use PIE buildmode\n")
 	fmt.Fprintf(output, "         --goos value    set GOOS for cross-compilation\n")
 	fmt.Fprintf(output, "         --goarch value  set GOARCH for cross-compilation\n")
+	fmt.Fprintf(output, "         --goarm value   set GOARM for cross-compilation\n")
 }
 
 func verbosePrintf(message string, args ...interface{}) {
@@ -232,49 +108,77 @@ func verbosePrintf(message string, args ...interface{}) {
 	fmt.Printf("build: "+message, args...)
 }
 
-// cleanEnv returns a clean environment with GOPATH and GOBIN removed (if
+// printEnv prints Go-relevant environment variables in a nice way using verbosePrintf.
-// present).
+func printEnv(env []string) {
-func cleanEnv() (env []string) {
+	verbosePrintf("environment (GO*):\n")
-	for _, v := range os.Environ() {
+	for _, v := range env {
-		if strings.HasPrefix(v, "GOPATH=") || strings.HasPrefix(v, "GOBIN=") {
+		// ignore environment variables which do not start with GO*.
+		if !strings.HasPrefix(v, "GO") {
 			continue
 		}
-
+		verbosePrintf("  %s\n", v)
-		env = append(env, v)
 	}
-
-	return env
 }
 
 // build runs "go build args..." with GOPATH set to gopath.
-func build(cwd, goos, goarch, gopath string, args ...string) error {
+func build(cwd string, env map[string]string, args ...string) error {
 	a := []string{"build"}
-	a = append(a, "-asmflags", fmt.Sprintf("-trimpath=%s", gopath))
+
-	a = append(a, "-gcflags", fmt.Sprintf("-trimpath=%s", gopath))
+	// try to remove all absolute paths from resulting binary
+	if goVersion.AtLeast(GoVersion{1, 13, 0}) {
+		// use the new flag introduced by Go 1.13
+		a = append(a, "-trimpath")
+	} else {
+		// otherwise try to trim as many paths as possible
+		a = append(a, "-asmflags", fmt.Sprintf("all=-trimpath=%s", cwd))
+		a = append(a, "-gcflags", fmt.Sprintf("all=-trimpath=%s", cwd))
+	}
+
+	if enablePIE {
+		a = append(a, "-buildmode=pie")
+	}
+
 	a = append(a, args...)
 	cmd := exec.Command("go", a...)
-	cmd.Env = append(cleanEnv(), "GOPATH="+gopath, "GOARCH="+goarch, "GOOS="+goos)
+	cmd.Env = os.Environ()
+	for k, v := range env {
+		cmd.Env = append(cmd.Env, k+"="+v)
+	}
 	if !enableCGO {
 		cmd.Env = append(cmd.Env, "CGO_ENABLED=0")
 	}
 
+	printEnv(cmd.Env)
+
 	cmd.Dir = cwd
 	cmd.Stdout = os.Stdout
 	cmd.Stderr = os.Stderr
-	verbosePrintf("go %s\n", args)
+
+	verbosePrintf("chdir %q\n", cwd)
+	verbosePrintf("go %q\n", a)
 
 	return cmd.Run()
 }
 
 // test runs "go test args..." with GOPATH set to gopath.
-func test(cwd, gopath string, args ...string) error {
+func test(cwd string, env map[string]string, args ...string) error {
-	args = append([]string{"test"}, args...)
+	args = append([]string{"test", "-count", "1"}, args...)
 	cmd := exec.Command("go", args...)
-	cmd.Env = append(cleanEnv(), "GOPATH="+gopath)
+	cmd.Env = os.Environ()
+	for k, v := range env {
+		cmd.Env = append(cmd.Env, k+"="+v)
+	}
+	if !enableCGO {
+		cmd.Env = append(cmd.Env, "CGO_ENABLED=0")
+	}
 	cmd.Dir = cwd
 	cmd.Stdout = os.Stdout
 	cmd.Stderr = os.Stderr
-	verbosePrintf("go %s\n", args)
+
+	printEnv(cmd.Env)
+
+	verbosePrintf("chdir %q\n", cwd)
+	verbosePrintf("go %q\n", args)
 
 	return cmd.Run()
 }
@@ -357,30 +261,39 @@ func ParseGoVersion(s string) (v GoVersion) {
 
 	s = s[2:]
 	data := strings.Split(s, ".")
-	if len(data) != 3 {
+	if len(data) < 2 || len(data) > 3 {
-		return
+		// invalid version
+		return GoVersion{}
 	}
 
-	major, err := strconv.Atoi(data[0])
+	var err error
+
+	v.Major, err = strconv.Atoi(data[0])
 	if err != nil {
-		return
+		return GoVersion{}
 	}
 
-	minor, err := strconv.Atoi(data[1])
+	// try to parse the minor version while removing an eventual suffix (like
-	if err != nil {
+	// "rc2" or so)
-		return
+	for s := data[1]; s != ""; s = s[:len(s)-1] {
+		v.Minor, err = strconv.Atoi(s)
+		if err == nil {
+			break
+		}
 	}
 
-	patch, err := strconv.Atoi(data[2])
+	if v.Minor == 0 {
-	if err != nil {
+		// no minor version found
-		return
+		return GoVersion{}
 	}
 
-	v = GoVersion{
+	if len(data) >= 3 {
-		Major: major,
+		v.Patch, err = strconv.Atoi(data[2])
-		Minor: minor,
+		if err != nil {
-		Patch: patch,
+			return GoVersion{}
+		}
 	}
+
 	return
 }
 
@@ -413,19 +326,26 @@ func (v GoVersion) String() string {
 }
 
 func main() {
-	ver := ParseGoVersion(runtime.Version())
+	if !goVersion.AtLeast(GoVersion{1, 11, 0}) {
-	if !ver.AtLeast(config.MinVersion) {
+		die("Go version (%v) is too old, Go <= 1.11 does not support Go Modules\n", goVersion)
-		fmt.Fprintf(os.Stderr, "%s detected, this program requires at least %s\n", ver, config.MinVersion)
+	}
+
+	if !goVersion.AtLeast(config.MinVersion) {
+		fmt.Fprintf(os.Stderr, "%s detected, this program requires at least %s\n", goVersion, config.MinVersion)
 		os.Exit(1)
 	}
 
-	buildTags := []string{}
+	buildTags := config.DefaultBuildTags
 
 	skipNext := false
 	params := os.Args[1:]
 
-	targetGOOS := runtime.GOOS
+	env := map[string]string{
-	targetGOARCH := runtime.GOARCH
+		"GO111MODULE": "on", // make sure we build in Module mode
+		"GOOS":        runtime.GOOS,
+		"GOARCH":      runtime.GOARCH,
+		"GOARM":       "",
+	}
 
 	var outputFilename string
 
@@ -438,14 +358,12 @@ func main() {
 		switch arg {
 		case "-v", "--verbose":
 			verbose = true
-		case "-k", "--keep-gopath":
-			keepGopath = true
 		case "-t", "-tags", "--tags":
 			if i+1 >= len(params) {
 				die("-t given but no tag specified")
 			}
 			skipNext = true
-			buildTags = strings.Split(params[i+1], " ")
+			buildTags = append(buildTags, strings.Split(params[i+1], " ")...)
 		case "-o", "--output":
 			skipNext = true
 			outputFilename = params[i+1]
@@ -453,12 +371,17 @@ func main() {
 			runTests = true
 		case "--enable-cgo":
 			enableCGO = true
+		case "--enable-pie":
+			enablePIE = true
 		case "--goos":
 			skipNext = true
-			targetGOOS = params[i+1]
+			env["GOOS"] = params[i+1]
 		case "--goarch":
 			skipNext = true
-			targetGOARCH = params[i+1]
+			env["GOARCH"] = params[i+1]
+		case "--goarm":
+			skipNext = true
+			env["GOARM"] = params[i+1]
 		case "-h":
 			showUsage(os.Stdout)
 			return
@@ -469,10 +392,7 @@ func main() {
 		}
 	}
 
-	if len(buildTags) == 0 {
+	verbosePrintf("detected Go version %v\n", goVersion)
-		verbosePrintf("adding build-tag release\n")
-		buildTags = []string{"release"}
-	}
 
 	for i := range buildTags {
 		buildTags[i] = strings.TrimSpace(buildTags[i])
@@ -485,48 +405,16 @@ func main() {
 		die("Getwd(): %v\n", err)
 	}
 
-	gopath, err := ioutil.TempDir("", fmt.Sprintf("%v-build-", config.Name))
-	if err != nil {
-		die("TempDir(): %v\n", err)
-	}
-
-	verbosePrintf("create GOPATH at %v\n", gopath)
-	if err = updateGopath(gopath, root, config.Namespace); err != nil {
-		die("copying files from %v/src to %v/src failed: %v\n", root, gopath, err)
-	}
-
-	vendor := filepath.Join(root, "vendor")
-	if directoryExists(vendor) {
-		if err = updateGopath(gopath, vendor, filepath.Join(config.Namespace, "vendor")); err != nil {
-			die("copying files from %v to %v failed: %v\n", root, gopath, err)
-		}
-	}
-
-	defer func() {
-		if !keepGopath {
-			verbosePrintf("remove %v\n", gopath)
-			if err = os.RemoveAll(gopath); err != nil {
-				die("remove GOPATH at %s failed: %v\n", err)
-			}
-		} else {
-			verbosePrintf("leaving temporary GOPATH at %v\n", gopath)
-		}
-	}()
-
 	if outputFilename == "" {
 		outputFilename = config.Name
-		if targetGOOS == "windows" {
+		if env["GOOS"] == "windows" {
 			outputFilename += ".exe"
 		}
 	}
 
-	cwd, err := os.Getwd()
-	if err != nil {
-		die("Getwd() returned %v\n", err)
-	}
 	output := outputFilename
 	if !filepath.IsAbs(output) {
-		output = filepath.Join(cwd, output)
+		output = filepath.Join(root, output)
 	}
 
 	version := getVersion()
@@ -537,13 +425,29 @@ func main() {
 	ldflags := "-s -w " + constants.LDFlags()
 	verbosePrintf("ldflags: %s\n", ldflags)
 
-	args := []string{
+	var (
-		"-tags", strings.Join(buildTags, " "),
+		buildArgs []string
-		"-ldflags", ldflags,
+		testArgs  []string
-		"-o", output, config.Main,
+	)
+
+	mainPackage := config.Main
+	if strings.HasPrefix(mainPackage, config.Namespace) {
+		mainPackage = strings.Replace(mainPackage, config.Namespace, "./", 1)
 	}
 
-	err = build(filepath.Join(gopath, "src"), targetGOOS, targetGOARCH, gopath, args...)
+	buildTarget := filepath.FromSlash(mainPackage)
+	buildCWD, err := os.Getwd()
+	if err != nil {
+		die("unable to determine current working directory: %v\n", err)
+	}
+
+	buildArgs = append(buildArgs,
+		"-tags", strings.Join(buildTags, " "),
+		"-ldflags", ldflags,
+		"-o", output, buildTarget,
+	)
+
+	err = build(buildCWD, env, buildArgs...)
 	if err != nil {
 		die("build failed: %v\n", err)
 	}
@@ -551,7 +455,9 @@ func main() {
 	if runTests {
 		verbosePrintf("running tests\n")
 
-		err = test(cwd, gopath, config.Tests...)
+		testArgs = append(testArgs, config.Tests...)
+
+		err = test(buildCWD, env, testArgs...)
 		if err != nil {
 			die("running tests failed: %v\n", err)
 		}