void executeBulk(Task task, final BulkRequest bulkRequest, final long startTimeNanos, final ActionListener<BulkResponse> listener, final AtomicArray<BulkItemResponse> responses ) {
        final ClusterState clusterState = clusterService.state();
        // TODO use timeout to wait here if its blocked...
        clusterState.blocks().globalBlockedRaiseException(ClusterBlockLevel.WRITE);

        final ConcreteIndices concreteIndices = new ConcreteIndices(clusterState, indexNameExpressionResolver);
        MetaData metaData = clusterState.metaData();
        for (int i = 0; i < bulkRequest.requests.size(); i++) {
            DocWriteRequest docWriteRequest = bulkRequest.requests.get(i);
            //the request can only be null because we set it to null in the previous step, so it gets ignored
            if (docWriteRequest == null) {
                continue;
            }
            if (addFailureIfIndexIsUnavailable(docWriteRequest, bulkRequest, responses, i, concreteIndices, metaData)) {
                continue;
            }
            Index concreteIndex = concreteIndices.resolveIfAbsent(docWriteRequest);
            try {
                switch (docWriteRequest.opType()) {
                    case CREATE:
                    case INDEX:
                        IndexRequest indexRequest = (IndexRequest) docWriteRequest;
                        MappingMetaData mappingMd = null;
                        final IndexMetaData indexMetaData =http://www.mamicode.com/ metaData.index(concreteIndex);
                        if (indexMetaData != null) {
                            mappingMd = indexMetaData.mappingOrDefault(indexRequest.type());
                        }
                        indexRequest.resolveRouting(metaData);
                        indexRequest.process(mappingMd, allowIdGeneration, concreteIndex.getName());
                        break;
                    case UPDATE:
                        TransportUpdateAction.resolveAndValidateRouting(metaData, concreteIndex.getName(), (UpdateRequest) docWriteRequest);
                        break;
                    case DELETE:
                        TransportDeleteAction.resolveAndValidateRouting(metaData, concreteIndex.getName(), (DeleteRequest) docWriteRequest);
                        break;
                    default: throw new AssertionError("request type not supported: [" + docWriteRequest.opType() + "]");
                }
            } catch (ElasticsearchParseException | RoutingMissingException e) {
                BulkItemResponse.Failure failure = new BulkItemResponse.Failure(concreteIndex.getName(), docWriteRequest.type(), docWriteRequest.id(), e);
                BulkItemResponse bulkItemResponse = new BulkItemResponse(i, docWriteRequest.opType(), failure);
                responses.set(i, bulkItemResponse);
                // make sure the request gets never processed again
                bulkRequest.requests.set(i, null);
            }
        }

        // first, go over all the requests and create a ShardId -> Operations mapping
        Map<ShardId, List<BulkItemRequest>> requestsByShard = new HashMap<>();
        for (int i = 0; i < bulkRequest.requests.size(); i++) {
            DocWriteRequest request = bulkRequest.requests.get(i);
            if (request == null) {
                continue;
            }
            String concreteIndex = concreteIndices.getConcreteIndex(request.index()).getName();
            ShardId shardId = clusterService.operationRouting().indexShards(clusterState, concreteIndex, request.id(), request.routing()).shardId();
            List<BulkItemRequest> shardRequests = requestsByShard.computeIfAbsent(shardId, shard -> new ArrayList<>());
            shardRequests.add(new BulkItemRequest(i, request));
        }

        if (requestsByShard.isEmpty()) {
            listener.onResponse(new BulkResponse(responses.toArray(new BulkItemResponse[responses.length()]), buildTookInMillis(startTimeNanos)));
            return;
        }

        final AtomicInteger counter = new AtomicInteger(requestsByShard.size());
        String nodeId = clusterService.localNode().getId();
        for (Map.Entry<ShardId, List<BulkItemRequest>> entry : requestsByShard.entrySet()) {
            final ShardId shardId = entry.getKey();
            final List<BulkItemRequest> requests = entry.getValue();
            BulkShardRequest bulkShardRequest = new BulkShardRequest(shardId, bulkRequest.getRefreshPolicy(),
                    requests.toArray(new BulkItemRequest[requests.size()]));
            bulkShardRequest.waitForActiveShards(bulkRequest.waitForActiveShards());
            bulkShardRequest.timeout(bulkRequest.timeout());
            if (task != null) {
                bulkShardRequest.setParentTask(nodeId, task.getId());
            }
            shardBulkAction.execute(bulkShardRequest, new ActionListener<BulkShardResponse>() {
                @Override
                public void onResponse(BulkShardResponse bulkShardResponse) {
                    for (BulkItemResponse bulkItemResponse : bulkShardResponse.getResponses()) {
                        // we may have no response if item failed
                        if (bulkItemResponse.getResponse() != null) {
                            bulkItemResponse.getResponse().setShardInfo(bulkShardResponse.getShardInfo());
                        }
                        responses.set(bulkItemResponse.getItemId(), bulkItemResponse);
                    }
                    if (counter.decrementAndGet() == 0) {
                        finishHim();
                    }
                }
            });
        }
    }