public function getTransformStr($taskname, $process_attrs)
    {
        $tranform_str = $taskname;
        if (count($process_attrs) > 0) {
            $tranform_str .= '=';
        }

        // append attributes if exists
        foreach ($process_attrs as $key => $value) {
            $encoded_value = gettype($value) === 'string' ?
                urlencode($value) : urlencode(json_encode($value));

            $tranform_str .= sprintf('%s:%s,',
                urlencode($key),
                $encoded_value);
        }

        // remove last comma
        if (count($process_attrs) > 0) {
            $tranform_str = substr($tranform_str, 0, strlen($tranform_str) - 1);
        }

        return $tranform_str;
    }