@Override
        public void run() {
            while (RUNNING.get()) {
                int retryTimes = 10;
                for (int time = 1; time <= retryTimes; time++) {
                    try {
                        //do long polling.
                        doLongPolling(server);
                    } catch (Exception e) {
                        // print warnning LOG.
                        if (time < retryTimes) {
                            LOG.warn("Long polling failed, tried {} times, {} times left, will be suspended for a while! {}",
                                    time, retryTimes - time, e.getMessage());
                            ThreadUtils.sleep(TimeUnit.SECONDS, 5);
                            continue;
                        }
                        // print error, then suspended for a while.
                        LOG.error("Long polling failed, try again after 5 minutes!", e);
                        ThreadUtils.sleep(TimeUnit.MINUTES, 5);
                    }
                }
            }
            LOG.warn("Stop http long polling.");
        }
update local cache.

@param json the response from config server.
@return true: the local cache was updated. false: not updated.
shenyu-sync-data-center/shenyu-sync-data-http/src/main/java/org/apache/shenyu/sync/data/http/HttpSyncDataService.java