@Service
public class ServerListService implements ApplicationListener<WebServerInitializedEvent> {
    @Autowired
    private Environment env;
    @Autowired
    private ServletContext servletContext;
    private int port;
    @PostConstruct
    public void init() {
        serverPort = System.getProperty("nacos.server.port", "8848");
        String envDomainName = System.getenv("address_server_domain");
        if (StringUtils.isBlank(envDomainName)) {
            domainName = System.getProperty("address.server.domain", "jmenv.tbsite.net");
        } else {
            domainName = envDomainName;
        }
        String envAddressPort = System.getenv("address_server_port");
        if (StringUtils.isBlank(envAddressPort)) {
            addressPort = System.getProperty("address.server.port", "8080");
        } else {
            addressPort = envAddressPort;
        }
        addressUrl = System.getProperty("address.server.url",
            servletContext.getContextPath() + "/" + RunningConfigUtils.getClusterName());
        addressServerUrl = "http://" + domainName + ":" + addressPort + addressUrl;
        envIdUrl = "http://" + domainName + ":" + addressPort + "/env";
        defaultLog.info("ServerListService address-server port:" + serverPort);
        defaultLog.info("ADDRESS_SERVER_URL:" + addressServerUrl);
        isHealthCheck = PropertyUtil.isHealthCheck();
        maxFailCount = PropertyUtil.getMaxHealthCheckFailCount();
        try {
            String val = null;
            val = env.getProperty("useAddressServer");
            if (val != null && FALSE_STR.equals(val)) {
                isUseAddressServer = false;
            }
            fatalLog.warn("useAddressServer:{}", isUseAddressServer);
        } catch (Exception e) {
            fatalLog.error("read application.properties wrong", e);
        }
        GetServerListTask task = new GetServerListTask();
        task.run();
        if (null == serverList || serverList.isEmpty()) {
            fatalLog.error("########## cannot get serverlist, so exit.");
            throw new RuntimeException("cannot get serverlist, so exit.");
        } else {
            TimerTaskService.scheduleWithFixedDelay(task, 0L, 5L, TimeUnit.SECONDS);
        }
        httpclient.start();
        CheckServerHealthTask checkServerHealthTask = new CheckServerHealthTask();
        TimerTaskService.scheduleWithFixedDelay(checkServerHealthTask, 0L, 5L, TimeUnit.SECONDS);
    }
}

private static String getClusterConfFilePath() {
        return NACOS_HOME + File.separator + "conf" + File.separator + "cluster.conf";
    }

class GetServerListTask implements Runnable {
        @Override
        public void run() {
            try {
                updateIfChanged(getApacheServerList());
            } catch (Exception e) {
                defaultLog.error("[serverlist] failed to get serverlist, " + e.toString(), e);
            }
        }
    }

private void checkServerHealth() {
        long startCheckTime = System.currentTimeMillis();
        for (String serverIp : serverList) {
            // Compatible with old codes,use status.taobao
            String url = "http://" + serverIp + servletContext.getContextPath() + Constants.HEALTH_CONTROLLER_PATH;
            // "/nacos/health";
            HttpGet request = new HttpGet(url);
            httpclient.execute(request, new AyscCheckServerHealthCallBack(serverIp));
        }
        long endCheckTime = System.currentTimeMillis();
        long cost = endCheckTime - startCheckTime;
        defaultLog.debug("checkServerHealth cost: {}", cost);
    }

String url = "http://" + serverIp + servletContext.getContextPath() + Constants.HEALTH_CONTROLLER_PATH;

class AyscCheckServerHealthCallBack implements FutureCallback<HttpResponse> {
        private String serverIp;
        public AyscCheckServerHealthCallBack(String serverIp) {
            this.serverIp = serverIp;
        }
        @Override
        public void completed(HttpResponse response) {
            if (response.getStatusLine().getStatusCode() == HttpServletResponse.SC_OK) {
                serverIp2unhealthCount.put(serverIp, 0);
                if (serverListUnhealth.contains(serverIp)) {
                    serverListUnhealth.remove(serverIp);
                }
                HttpClientUtils.closeQuietly(response);
            }
        }
        @Override
        public void failed(Exception ex) {
            Integer failCount = serverIp2unhealthCount.get(serverIp);
            failCount = failCount == null ? Integer.valueOf(0) : failCount;
            failCount++;
            serverIp2unhealthCount.put(serverIp, failCount);
            if (failCount > maxFailCount) {
                if (!serverListUnhealth.contains(serverIp)) {
                    serverListUnhealth.add(serverIp);
                }
                defaultLog.error("unhealthIp:{}, unhealthCount:{}", serverIp, failCount);
                MetricsMonitor.getUnhealthException().increment();
            }
        }
    }