build: set provenance vcs details

Signed-off-by: CrazyMax <crazy-max@users.noreply.github.com>

util/gitutil/gitutil.go

@@ -0,0 +1,123 @@
+package gitutil
+
+import (
+	"bytes"
+	"context"
+	"os/exec"
+	"strings"
+
+	"github.com/pkg/errors"
+)
+
+// Git represents an active git object
+type Git struct {
+	ctx context.Context
+	wd  string
+}
+
+// Option provides a variadic option for configuring the git client.
+type Option func(b *Git)
+
+// WithContext sets context.
+func WithContext(ctx context.Context) Option {
+	return func(b *Git) {
+		b.ctx = ctx
+	}
+}
+
+// WithWorkingDir sets working directory.
+func WithWorkingDir(wd string) Option {
+	return func(b *Git) {
+		b.wd = wd
+	}
+}
+
+// New initializes a new git client
+func New(opts ...Option) *Git {
+	c := &Git{
+		ctx: context.Background(),
+	}
+	for _, opt := range opts {
+		opt(c)
+	}
+	return c
+}
+
+func (c *Git) IsInsideWorkTree() bool {
+	out, err := c.clean(c.run("rev-parse", "--is-inside-work-tree"))
+	return out == "true" && err == nil
+}
+
+func (c *Git) IsDirty() bool {
+	out, err := c.run("status", "--porcelain", "--ignored")
+	return strings.TrimSpace(out) != "" || err != nil
+}
+
+func (c *Git) RootDir() (string, error) {
+	return c.clean(c.run("rev-parse", "--show-toplevel"))
+}
+
+func (c *Git) RemoteURL() (string, error) {
+	return c.clean(c.run("ls-remote", "--get-url"))
+}
+
+func (c *Git) FullCommit() (string, error) {
+	return c.clean(c.run("show", "--format=%H", "HEAD", "--quiet"))
+}
+
+func (c *Git) ShortCommit() (string, error) {
+	return c.clean(c.run("show", "--format=%h", "HEAD", "--quiet"))
+}
+
+func (c *Git) Tag() (string, error) {
+	var tag string
+	var err error
+	for _, fn := range []func() (string, error){
+		func() (string, error) {
+			return c.clean(c.run("tag", "--points-at", "HEAD", "--sort", "-version:creatordate"))
+		},
+		func() (string, error) {
+			return c.clean(c.run("describe", "--tags", "--abbrev=0"))
+		},
+	} {
+		tag, err = fn()
+		if tag != "" || err != nil {
+			return tag, err
+		}
+	}
+	return tag, err
+}
+
+func (c *Git) run(args ...string) (string, error) {
+	if _, err := exec.LookPath("git"); err != nil {
+		return "", errors.New("git not present in PATH")
+	}
+
+	var extraArgs = []string{
+		"-c", "log.showSignature=false",
+	}
+
+	args = append(extraArgs, args...)
+	cmd := exec.Command("git", args...)
+	if c.wd != "" {
+		cmd.Dir = c.wd
+	}
+
+	stdout := bytes.Buffer{}
+	stderr := bytes.Buffer{}
+	cmd.Stdout = &stdout
+	cmd.Stderr = &stderr
+
+	if err := cmd.Run(); err != nil {
+		return "", errors.New(stderr.String())
+	}
+	return stdout.String(), nil
+}
+
+func (c *Git) clean(out string, err error) (string, error) {
+	out = strings.ReplaceAll(strings.Split(out, "\n")[0], "'", "")
+	if err != nil {
+		err = errors.New(strings.TrimSuffix(err.Error(), "\n"))
+	}
+	return out, err
+}

util/gitutil/gitutil_test.go

@@ -0,0 +1,69 @@
+package gitutil
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestGit(t *testing.T) {
+	c := New()
+	out, err := c.run("status")
+	require.NoError(t, err)
+	require.NotEmpty(t, out)
+
+	out, err = c.clean(c.run("not-exist"))
+	require.Error(t, err)
+	require.Empty(t, out)
+	require.Equal(t, "git: 'not-exist' is not a git command. See 'git --help'.", err.Error())
+}
+
+func TestGitFullCommit(t *testing.T) {
+	Mktmp(t)
+	GitInit(t)
+	GitCommit(t, "bar")
+
+	c := New()
+	out, err := c.FullCommit()
+	require.NoError(t, err)
+	require.Equal(t, 40, len(out))
+}
+
+func TestGitShortCommit(t *testing.T) {
+	Mktmp(t)
+	GitInit(t)
+	GitCommit(t, "bar")
+
+	c := New()
+	out, err := c.ShortCommit()
+	require.NoError(t, err)
+	require.Equal(t, 7, len(out))
+}
+
+func TestGitTagsPointsAt(t *testing.T) {
+	Mktmp(t)
+	GitInit(t)
+	GitCommit(t, "bar")
+	GitTag(t, "v0.8.0")
+	GitCommit(t, "foo")
+	GitTag(t, "v0.9.0")
+
+	c := New()
+	out, err := c.clean(c.run("tag", "--points-at", "HEAD", "--sort", "-version:creatordate"))
+	require.NoError(t, err)
+	require.Equal(t, "v0.9.0", out)
+}
+
+func TestGitDescribeTags(t *testing.T) {
+	Mktmp(t)
+	GitInit(t)
+	GitCommit(t, "bar")
+	GitTag(t, "v0.8.0")
+	GitCommit(t, "foo")
+	GitTag(t, "v0.9.0")
+
+	c := New()
+	out, err := c.clean(c.run("describe", "--tags", "--abbrev=0"))
+	require.NoError(t, err)
+	require.Equal(t, "v0.9.0", out)
+}

util/gitutil/testutil.go

@@ -0,0 +1,76 @@
+package gitutil
+
+import (
+	"os"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func GitInit(tb testing.TB) {
+	tb.Helper()
+	out, err := fakeGit("init")
+	require.NoError(tb, err)
+	require.Contains(tb, out, "Initialized empty Git repository")
+	require.NoError(tb, err)
+	GitCheckoutBranch(tb, "main")
+	_, _ = fakeGit("branch", "-D", "master")
+}
+
+func GitCommit(tb testing.TB, msg string) {
+	tb.Helper()
+	out, err := fakeGit("commit", "--allow-empty", "-m", msg)
+	require.NoError(tb, err)
+	require.Contains(tb, out, "main", msg)
+}
+
+func GitTag(tb testing.TB, tag string) {
+	tb.Helper()
+	out, err := fakeGit("tag", tag)
+	require.NoError(tb, err)
+	require.Empty(tb, out)
+}
+
+func GitCheckoutBranch(tb testing.TB, name string) {
+	tb.Helper()
+	out, err := fakeGit("checkout", "-b", name)
+	require.NoError(tb, err)
+	require.Empty(tb, out)
+}
+
+func GitAdd(tb testing.TB, file string) {
+	tb.Helper()
+	_, err := fakeGit("add", file)
+	require.NoError(tb, err)
+}
+
+func GitSetRemote(tb testing.TB, url string) {
+	tb.Helper()
+	_, err := fakeGit("remote", "add", "origin", url)
+	require.NoError(tb, err)
+}
+
+func Mktmp(tb testing.TB) string {
+	tb.Helper()
+	folder := tb.TempDir()
+	current, err := os.Getwd()
+	require.NoError(tb, err)
+	require.NoError(tb, os.Chdir(folder))
+	tb.Cleanup(func() {
+		require.NoError(tb, os.Chdir(current))
+	})
+	return folder
+}
+
+func fakeGit(args ...string) (string, error) {
+	allArgs := []string{
+		"-c", "user.name=buildx",
+		"-c", "user.email=buildx@docker.com",
+		"-c", "commit.gpgSign=false",
+		"-c", "tag.gpgSign=false",
+		"-c", "log.showSignature=false",
+	}
+	allArgs = append(allArgs, args...)
+	c := New()
+	return c.clean(c.run(allArgs...))
+}