try {
            final SearchEngineClient esClient = ComponentUtil.getSearchEngineClient();
            final NodesStatsResponse response = esClient.admin().cluster().prepareNodesStats().all().execute().actionGet(10000L);
            final XContentBuilder builder = XContentFactory.jsonBuilder();
            builder.startObject();
            response.toXContent(builder, ToXContent.EMPTY_PARAMS);
            builder.endObject();

     */
    public <T> T get(final Function<FesenClient, ActionFuture<T>> func) {
        int retryCount = 0;
        while (true) {
            try {
                return func.apply(this).actionGet(connTimeout, TimeUnit.MILLISECONDS);
            } catch (final IndexNotFoundException | VersionConflictEngineException e) {
                logger.debug("{} occurs.", e.getClass().getName(), e);
                throw e;

            runner.close();
            runner.clean();
        }
    }

    @Before
    public void before() throws Exception {
        runner.admin().indices().prepareDelete("_all").execute().actionGet();
        runner.refresh();
        suggester = Suggester.builder().build(runner.client(), "DefaultContentsParserTest");
        suggester.createIndexIfNothing();
    }

    @Test

        searchEngineClient.admin()
                .cluster()
                .prepareHealth()
                .setWaitForYellowStatus()
                .execute()
                .actionGet(fessConfig.getIndexHealthTimeout());

        final SuggestSettingsBuilder settingsBuilder = SuggestSettings.builder();
        settingsBuilder.addInitialSettings("search_engine.type", fessConfig.getFesenType());

                        numberOfSuggestDocs += res.getNumberOfSuggestDocs();
                        numberOfInputDocs += res.getNumberOfInputDocs();
                        client.admin().indices().prepareRefresh(index).execute().actionGet(settings.getIndicesTimeout());
                        docs.clear();

                        waitController.run();
                    }
                }

                deferred.resolve(

        try {
            final SearchEngineClient esClient = ComponentUtil.getSearchEngineClient();
            final ClusterHealthResponse response =
                    esClient.admin().cluster().prepareHealth().execute().actionGet(fessConfig.getIndexHealthTimeout());
            engineObj.clusterName = response.getClusterName();
            engineObj.numberOfNodes = response.getNumberOfNodes();

                final String index = fessConfig.getIndexDocumentUpdateIndex();
                searchEngineClient.admin().indices().prepareRefresh(index).execute().actionGet();
                final long numOfDeleted = searchEngineClient.deleteByQuery(index, queryBuilder);
                logger.info("[{}] Deleted {} stale documents.", dataConfig.getName(), numOfDeleted);

        final AtomicInteger attemptCount = new AtomicInteger(0);
        final ActionFuture<String> mockFuture = mock(ActionFuture.class);

        // Fail 5 times, succeed on 6th attempt
        when(mockFuture.actionGet(anyLong(), any(TimeUnit.class))).thenAnswer(invocation -> {
            int count = attemptCount.incrementAndGet();
            if (count <= 5) {
                throw new RuntimeException("Simulated failure #" + count);

            builderLambda.accept(builder);
            final UpdateResponse response = builder.execute().actionGet(fessConfig.getIndexIndexTimeout());
            return response.getResult() == Result.CREATED || response.getResult() == Result.UPDATED;
        } catch (final OpenSearchException e) {