private String getUrl(DingtalkSettings.WebHookUrl webHookUrl) {
        if (StringUtil.isEmpty(webHookUrl.getSecret())) {
            return webHookUrl.getUrl();
        }
        return getSignUrl(webHookUrl);
    }
Get webhook url, sign the url when secret is not empty.
oap-server/server-alarm-plugin/src/main/java/org/apache/skywalking/oap/server/core/alarm/provider/dingtalk/DingtalkHookCallback.java