func DecompressZip(src string, target string) error {
    f, err := os.Open(src)
    if err != nil {
        return errors.Wrap(err, "can't open tar source file:"+src)
    }
    defer f.Close()
    zipReader, err := gzip.NewReader(f)
    if err != nil {
        return errors.Wrap(err, "can't gzip source file"+src)
    }
    defer zipReader.Close()
    unzipFile, err := CreateFileAnyway(target) // return *os.file
    if err != nil {
        return errors.Wrap(err, "can't create target file"+target)
    }
    defer unzipFile.Close()
    if _, err := io.Copy(unzipFile, zipReader); err != nil {
        return errors.Wrap(err, "can't unzip to file :"+target)
    }
    return nil
}