code: func CreateTarStream(path string) (io.ReadCloser, error) {
  	tarOpts := &archive.TarOptions{
  		ExcludePatterns: []string{},
  		IncludeFiles:    []string{"."},
  		Compression:     archive.Uncompressed,
  		NoLchown:        true,
  	}
  	tar, err := archive.TarWithOptions(path, tarOpts)
  	if err != nil {
  		return nil, err
  	}
  	return buildContext{path, tar}, nil
  }
docs: // CreateTarStream create a tar stream