@Override
  protected ClusterStatsNodeResponse nodeOperation(ClusterStatsNodeRequest nodeRequest) {
    NodeInfo nodeInfo = nodeService.info(false, true, false, true, false, true, false, true);
    NodeStats nodeStats =
        nodeService.stats(
            CommonStatsFlags.NONE,
            false,
            true,
            true,
            false,
            true,
            false,
            false,
            false,
            false,
            false);
    List<ShardStats> shardsStats = new ArrayList<>();
    for (IndexService indexService : indicesService) {
      for (IndexShard indexShard : indexService) {
        if (indexShard.routingEntry() != null && indexShard.routingEntry().active()) {
          // only report on fully started shards
          shardsStats.add(
              new ShardStats(
                  indexShard.routingEntry(),
                  indexShard.shardPath(),
                  new CommonStats(
                      indicesService.getIndicesQueryCache(), indexShard, SHARD_STATS_FLAGS),
                  indexShard.commitStats()));
        }
      }
    }

    ClusterHealthStatus clusterStatus = null;
    if (clusterService.state().nodes().localNodeMaster()) {
      clusterStatus = new ClusterStateHealth(clusterService.state()).getStatus();
    }

    return new ClusterStatsNodeResponse(
        nodeInfo.getNode(),
        clusterStatus,
        nodeInfo,
        nodeStats,
        shardsStats.toArray(new ShardStats[shardsStats.size()]));
  }
  public synchronized IndexShard createShard(ShardRouting routing) throws IOException {
    final boolean primary = routing.primary();
    /*
     * TODO: we execute this in parallel but it's a synced method. Yet, we might
     * be able to serialize the execution via the cluster state in the future. for now we just
     * keep it synced.
     */
    if (closed.get()) {
      throw new IllegalStateException("Can't create shard " + routing.shardId() + ", closed");
    }
    final Settings indexSettings = this.indexSettings.getSettings();
    final ShardId shardId = routing.shardId();
    boolean success = false;
    Store store = null;
    IndexShard indexShard = null;
    ShardLock lock = null;
    try {
      lock = nodeEnv.shardLock(shardId, TimeUnit.SECONDS.toMillis(5));
      eventListener.beforeIndexShardCreated(shardId, indexSettings);
      ShardPath path;
      try {
        path = ShardPath.loadShardPath(logger, nodeEnv, shardId, this.indexSettings);
      } catch (IllegalStateException ex) {
        logger.warn("{} failed to load shard path, trying to remove leftover", shardId);
        try {
          ShardPath.deleteLeftoverShardDirectory(logger, nodeEnv, lock, this.indexSettings);
          path = ShardPath.loadShardPath(logger, nodeEnv, shardId, this.indexSettings);
        } catch (Exception inner) {
          ex.addSuppressed(inner);
          throw ex;
        }
      }

      if (path == null) {
        // TODO: we should, instead, hold a "bytes reserved" of how large we anticipate this shard
        // will be, e.g. for a shard
        // that's being relocated/replicated we know how large it will become once it's done
        // copying:
        // Count up how many shards are currently on each data path:
        Map<Path, Integer> dataPathToShardCount = new HashMap<>();
        for (IndexShard shard : this) {
          Path dataPath = shard.shardPath().getRootStatePath();
          Integer curCount = dataPathToShardCount.get(dataPath);
          if (curCount == null) {
            curCount = 0;
          }
          dataPathToShardCount.put(dataPath, curCount + 1);
        }
        path =
            ShardPath.selectNewPathForShard(
                nodeEnv,
                shardId,
                this.indexSettings,
                routing.getExpectedShardSize() == ShardRouting.UNAVAILABLE_EXPECTED_SHARD_SIZE
                    ? getAvgShardSizeInBytes()
                    : routing.getExpectedShardSize(),
                dataPathToShardCount);
        logger.debug("{} creating using a new path [{}]", shardId, path);
      } else {
        logger.debug("{} creating using an existing path [{}]", shardId, path);
      }

      if (shards.containsKey(shardId.id())) {
        throw new IndexShardAlreadyExistsException(shardId + " already exists");
      }

      logger.debug("creating shard_id {}", shardId);
      // if we are on a shared FS we only own the shard (ie. we can safely delete it) if we are the
      // primary.
      final boolean canDeleteShardContent =
          IndexMetaData.isOnSharedFilesystem(indexSettings) == false
              || (primary && IndexMetaData.isOnSharedFilesystem(indexSettings));
      final Engine.Warmer engineWarmer =
          (searcher) -> {
            IndexShard shard = getShardOrNull(shardId.getId());
            if (shard != null) {
              warmer.warm(searcher, shard, IndexService.this.indexSettings);
            }
          };
      store =
          new Store(
              shardId,
              this.indexSettings,
              indexStore.newDirectoryService(path),
              lock,
              new StoreCloseListener(
                  shardId, canDeleteShardContent, () -> eventListener.onStoreClosed(shardId)));
      if (useShadowEngine(primary, indexSettings)) {
        indexShard =
            new ShadowIndexShard(
                routing,
                this.indexSettings,
                path,
                store,
                indexCache,
                mapperService,
                similarityService,
                indexFieldData,
                engineFactory,
                eventListener,
                searcherWrapper,
                threadPool,
                bigArrays,
                engineWarmer,
                searchOperationListeners);
        // no indexing listeners - shadow  engines don't index
      } else {
        indexShard =
            new IndexShard(
                routing,
                this.indexSettings,
                path,
                store,
                indexCache,
                mapperService,
                similarityService,
                indexFieldData,
                engineFactory,
                eventListener,
                searcherWrapper,
                threadPool,
                bigArrays,
                engineWarmer,
                searchOperationListeners,
                indexingOperationListeners);
      }
      eventListener.indexShardStateChanged(indexShard, null, indexShard.state(), "shard created");
      eventListener.afterIndexShardCreated(indexShard);
      shards = newMapBuilder(shards).put(shardId.id(), indexShard).immutableMap();
      success = true;
      return indexShard;
    } catch (ShardLockObtainFailedException e) {
      throw new IOException("failed to obtain in-memory shard lock", e);
    } finally {
      if (success == false) {
        if (lock != null) {
          IOUtils.closeWhileHandlingException(lock);
        }
        closeShard("initialization failed", shardId, indexShard, store, eventListener);
      }
    }
  }