@Override
    public String get(String workflowInstanceId, String fieldToGet) {
        String docType = StringUtils.isBlank(docTypeOverride) ? WORKFLOW_DOC_TYPE : docTypeOverride;
        GetRequest request =
                new GetRequest(workflowIndexName, docType, workflowInstanceId)
                        .fetchSourceContext(
                                new FetchSourceContext(
                                        true, new String[] {fieldToGet}, Strings.EMPTY_ARRAY));
        GetResponse response = elasticSearchClient.get(request).actionGet();

        if (response.isExists()) {
            Map<String, Object> sourceAsMap = response.getSourceAsMap();
            if (sourceAsMap.get(fieldToGet) != null) {
                return sourceAsMap.get(fieldToGet).toString();
            }
        }

        LOGGER.debug(
                "Unable to find Workflow: {} in ElasticSearch index: {}.",
                workflowInstanceId,
                workflowIndexName);
        return null;
    }
Initializes the indexes templates task_log, message and event, and mappings.
es6-persistence/src/main/java/com/netflix/conductor/es6/dao/index/ElasticSearchDAOV6.java