def create_zipfile(self, filename):
    zip_file = zipfile.ZipFile(filename, "w")
    try:
        self.mkpath(self.target_dir)  # just in case
        for root, dirs, files in os.walk(self.target_dir):
            if root == self.target_dir and not files:
                raise DistutilsOptionError(
                    "no files found in upload directory '%s'"
                    % self.target_dir)
            for name in files:
                full = os.path.join(root, name)
                relative = root[len(self.target_dir):].lstrip(os.path.sep)
                dest = os.path.join(relative, name)
                zip_file.write(full, dest)
    finally:
        zip_file.close()