async function generateAuthCodeForUser(req, res) {
        const session = await getSession(req, res);
        const secret = getSettingsCache('admin_session_secret') + session.user_id;
        const token = totp.generate(secret);
        return token;
    }
generateAuthCodeForUser

@param {Req} req
@param {Res} res
@returns {Promise<string>}