public function logMessageToFile($message, $file_name)
    {
        $file = $this->log_path . $file_name;
        
        if ((!file_exists($file) && is_writable($this->log_path)) || is_writable($file)) {
            return error_log($message . "\r\n", 3, $file);
        } else {
            throw new \Exception(sprintf("The log file '%s' is not writable!", $file));
        }
    }