Data prepper Opensearch_api: return value for _bulk endpoint is wrong

dpsmails · May 15, 2026, 9:58am

Versions (relevant - OpenSearch/Dashboard/Server OS/Browser): Latest

Describe the issue:

This is for opensearch_api source in data prepper.

The _bulk endpoint returned an empty HTTP 200 with no body.

Clients using RestHighLevelClient (Flink, Logstash, opensearch-py) expect a JSON response with {took, errors, items [ ] } and fail with ‘Unable to parse response body’ / NullPointerException.

Configuration:

Relevant Logs or Screenshots:

pablo · May 15, 2026, 9:44pm

@dpsmails According to the Data Prepper GitHub, the processBulkRequest returns only HTTPS 200 OK.

github.com/opensearch-project/data-prepper

data-prepper-plugins/opensearch-api-source/src/main/java/org/opensearch/dataprepper/plugins/source/opensearchapi/OpenSearchAPIService.java

513dcfb06


      
                                              @Param("pipeline") @Nullable String pipeline,
                                              @Param("routing") @Nullable String routing) throws Exception {
              BulkAPIRequestParams bulkAPIRequestParams = BulkAPIRequestParams.builder()
                      .index(index)
                      .pipeline(pipeline)
                      .routing(routing)
                      .build();
              return requestProcessDuration.recordCallable(() -> processBulkRequest(serviceRequestContext, aggregatedHttpRequest, bulkAPIRequestParams));
          }
          
          private HttpResponse processBulkRequest(final ServiceRequestContext serviceRequestContext, final AggregatedHttpRequest aggregatedHttpRequest, final BulkAPIRequestParams bulkAPIRequestParams) throws Exception {
              requestsReceivedCounter.increment();
              payloadSizeSummary.record(aggregatedHttpRequest.content().length());
          
              if (serviceRequestContext.isTimedOut()) {
                  return HttpResponse.of(HttpStatus.REQUEST_TIMEOUT);
              }
          
              final HttpData content = aggregatedHttpRequest.content();
              List<Map<String, Object>> bulkRequestPayloadList;

I couldn’t find any GitHub issues reporting this problem. I would suggest reporting it in the Data Prepper GitHub repo. If you do so, please share the link here.

dpsmails · May 21, 2026, 6:15am

@pablo here it is: [BUG] opensearch_api source: _bulk endpoint returns empty HTTP 200 with no JSON body · Issue #6877 · opensearch-project/data-prepper · GitHub

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Data prepper Opensearch_api: return value for _bulk endpoint is wrong

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