package fsutil import ( "archive/tar" "context" "io" "os" "path/filepath" "strings" "github.com/pkg/errors" "github.com/tonistiigi/fsutil/types" ) func WriteTar(ctx context.Context, fs FS, w io.Writer) error { tw := tar.NewWriter(w) err := fs.Walk(ctx, func(path string, fi os.FileInfo, err error) error { stat, ok := fi.Sys().(*types.Stat) if !ok { return errors.Wrapf(err, "invalid fileinfo without stat info: %s", path) } hdr, err := tar.FileInfoHeader(fi, stat.Linkname) if err != nil { return err } name := filepath.ToSlash(path) if fi.IsDir() && !strings.HasSuffix(name, "/") { name += "/" } hdr.Name = name hdr.Uid = int(stat.Uid) hdr.Gid = int(stat.Gid) hdr.Devmajor = stat.Devmajor hdr.Devminor = stat.Devminor hdr.Linkname = stat.Linkname if hdr.Linkname != "" { hdr.Size = 0 if fi.Mode() & os.ModeSymlink != 0 { hdr.Typeflag = tar.TypeSymlink } else { hdr.Typeflag = tar.TypeLink } } if len(stat.Xattrs) > 0 { hdr.PAXRecords = map[string]string{} } for k, v := range stat.Xattrs { hdr.PAXRecords["SCHILY.xattr."+k] = string(v) } if err := tw.WriteHeader(hdr); err != nil { return errors.Wrap(err, "failed to write file header") } if hdr.Typeflag == tar.TypeReg && hdr.Size > 0 && hdr.Linkname == "" { rc, err := fs.Open(path) if err != nil { return err } if _, err := io.Copy(tw, rc); err != nil { return err } if err := rc.Close(); err != nil { return err } } return nil }) if err != nil { return err } return tw.Close() }