func writeACI(layer io.ReadSeeker, manifest schema.ImageManifest, curPwl []string, output string, compress bool) (*schema.ImageManifest, error) {
aciFile, err := os.Create(output)
if err != nil {
return nil, fmt.Errorf("error creating ACI file: %v", err)
}
defer aciFile.Close()
var w io.WriteCloser = aciFile
if compress {
w = gzip.NewWriter(aciFile)
defer w.Close()
}
trw := tar.NewWriter(w)
defer trw.Close()
if err := WriteRootfsDir(trw); err != nil {
return nil, fmt.Errorf("error writing rootfs entry: %v", err)
}
var whiteouts []string
convWalker := func(t *tarball.TarFile) error {
name := t.Name()
if name == "./" {
return nil
}
t.Header.Name = path.Join("rootfs", name)
absolutePath := strings.TrimPrefix(t.Header.Name, "rootfs")
if strings.Contains(t.Header.Name, "/.wh.") {
whiteouts = append(whiteouts, strings.Replace(absolutePath, ".wh.", "", 1))
return nil
}
if t.Header.Typeflag == tar.TypeLink {
t.Header.Linkname = path.Join("rootfs", t.Linkname())
}
if err := trw.WriteHeader(t.Header); err != nil {
return err
}
if _, err := io.Copy(trw, t.TarStream); err != nil {
return err
}
if !util.In(curPwl, absolutePath) {
curPwl = append(curPwl, absolutePath)
}
return nil
}
reader, err := aci.NewCompressedTarReader(layer)
if err == nil {
// write files in rootfs/
if err := tarball.Walk(*reader, convWalker); err != nil {
return nil, err
}
} else {
// ignore errors: empty layers in tars generated by docker save are not
// valid tar files so we ignore errors trying to open them. Converted
// ACIs will have the manifest and an empty rootfs directory in any
// case.
}
newPwl := subtractWhiteouts(curPwl, whiteouts)
manifest.PathWhitelist = newPwl
if err := WriteManifest(trw, manifest); err != nil {
return nil, fmt.Errorf("error writing manifest: %v", err)
}
return &manifest, nil
}
