What causes "DELETE {endpoint} response null" in apache/seatunnel?

Verify with a manual DELETE (on a test index) that the endpoint permits DELETE verbs end-to-end

apache/seatunnel · error · ElasticsearchConnectorException

DROP_INDEX_FAILED

DROP_INDEX_FAILED

Error message

DELETE {endpoint} response null

What it means

Logged/raised inside EsRestClient when a DELETE request against an Elasticsearch endpoint completes without returning a response body, so the deletion result cannot be confirmed. It signals an unexpected empty REST response rather than an HTTP error status.

Source

Thrown at seatunnel-connectors-v2/connector-elasticsearch/src/main/java/org/apache/seatunnel/connectors/seatunnel/elasticsearch/client/EsRestClient.java:644

                throw new ElasticsearchConnectorException(
                        ElasticsearchConnectorErrorCode.CREATE_INDEX_FAILED,
                        String.format(
                                "PUT %s response status code=%d, body=%s",
                                endpoint, response.getStatusLine().getStatusCode(), entity));
            }
        } catch (IOException ex) {
            throw new ElasticsearchConnectorException(
                    ElasticsearchConnectorErrorCode.CREATE_INDEX_FAILED, ex);
        }
    }

    public void dropIndex(String tableName) {
        String endpoint = String.format("/%s", tableName.toLowerCase());
        Request request = new Request("DELETE", endpoint);
        try {
            Response response = restClient.performRequest(request);
            if (response == null) {
                throw new ElasticsearchConnectorException(
                        ElasticsearchConnectorErrorCode.DROP_INDEX_FAILED,
                        "DELETE " + endpoint + " response null");
            }
            String entity = EntityUtils.toString(response.getEntity(), StandardCharsets.UTF_8);
            if (response.getStatusLine().getStatusCode() != HttpStatus.SC_OK) {
                throw new ElasticsearchConnectorException(
                        ElasticsearchConnectorErrorCode.DROP_INDEX_FAILED,
                        String.format(
                                "DELETE %s response status code=%d, body=%s",
                                endpoint, response.getStatusLine().getStatusCode(), entity));
            }
        } catch (IOException ex) {
            throw new ElasticsearchConnectorException(
                    ElasticsearchConnectorErrorCode.DROP_INDEX_FAILED, ex);
        }
    }

    public void clearIndexData(String indexName) {

View on GitHub (pinned to cf67b549a7)

Solutions

Verify with a manual DELETE (on a test index) that the endpoint permits DELETE verbs end-to-end
Use the standard ES Low Level REST Client without response-swallowing wrappers
Inspect proxy/WAF logs for blocked DELETE requests
Trace the REST client to confirm whether Elasticsearch processed the deletion

Defensive patterns

Strategy: try-catch

Type guard

boolean hasResponse(Response r) { return r != null; }

Try / catch

try {
    client.dropIndex(tableName);
} catch (ElasticsearchConnectorException e) {
    if (e.getMessage().contains("response null")) {
        // verify with HEAD /{index} whether the deletion actually happened
        if (!client.indexExists(tableName)) return; // already gone
    }
    throw e;
}

Prevention

Avoid proxies that block or swallow DELETE responses
Re-check index existence after a null-response failure instead of blindly retrying
Keep the REST client on standard, supported construction paths

When it happens

Trigger: dropIndex(tableName) invocation where restClient.performRequest returns null for the DELETE request.

Common situations: Wrapped/custom RestClient implementations; intermediaries dropping DELETE responses; DELETE requests blocked by some proxies/WAFs by policy.

Understand the failure class

Background: 'Something went wrong' / 'Request failed (500)' / 'HTTP error! status: 404' — what failed HTTP requests actually mean and how to find the real cause — this error's family across 28 libraries.

Related errors

AI-assisted analysis of apache/seatunnel@cf67b549a7 (2026-09-10). Data as JSON: /api/errors/15f07da699b8c2e2. Report an issue: GitHub.