elastic/elasticsearch · error · IllegalArgumentException

field [{}] is null, cannot process it.

Error message

field [{}] is null, cannot process it.

What it means

Thrown by CsvProcessor.execute when the configured source field is null or absent and 'ignore_missing' is false (default). Identical pattern to other ingest processors: getFieldValue is called with ignoreMissing, and a null result without ignore_missing short-circuits is an unrecoverable error. Note 'headers' being empty causes an early no-op return before this check.

Source

Thrown at modules/ingest-common/src/main/java/org/elasticsearch/ingest/common/CsvProcessor.java:80

        this.headers = headers;
        this.trim = trim;
        this.quote = quote;
        this.separator = separator;
        this.ignoreMissing = ignoreMissing;
        this.emptyValue = emptyValue;
    }

    @Override
    public IngestDocument execute(IngestDocument ingestDocument) {
        if (headers.length == 0) {
            return ingestDocument;
        }

        String line = ingestDocument.getFieldValue(field, String.class, ignoreMissing);
        if (line == null && ignoreMissing) {
            return ingestDocument;
        } else if (line == null) {
            throw new IllegalArgumentException("field [" + field + "] is null, cannot process it.");
        }
        new CsvParser(ingestDocument, quote, separator, trim, headers, emptyValue).process(line);
        return ingestDocument;
    }

    @Override
    public String getType() {
        return TYPE;
    }

    public static final class Factory implements org.elasticsearch.ingest.Processor.Factory {
        @Override
        public CsvProcessor create(
            Map<String, Processor.Factory> registry,
            String processorTag,
            String description,
            Map<String, Object> config,
            ProjectId projectId

View on GitHub (pinned to db6a809a66)

Solutions

1. Set 'ignore_missing: true' on the csv processor to skip documents lacking the field.
2. Verify the configured 'field' name matches what prior processors (or the source) produce.
3. Add a default value via a 'set' processor conditioned on field presence before the csv step.

Example fix

// before
{"csv": {"field": "message", "target_fields": ["a","b"]}}
// after
{"csv": {"field": "message", "target_fields": ["a","b"], "ignore_missing": true}}

// Default ignore_missing on the csv processor for optional message fields.
{"csv": {"field": "message", "target_fields": ["a","b"], "ignore_missing": true}}

{"on_failure": [{"index": {"index": "ingest-dlq"}}]}

When it happens

Trigger: A csv processor configured on a field that is null or absent in the incoming document, with 'ignore_missing' omitted or set to false.

Common situations: Optional message fields that are sometimes absent; pipeline reused across multiple ingest streams where only some have the CSV field; field renamed upstream and the csv processor still references the old name.

Related errors

• Field [{}] is null, cannot be converted to type [{}]
• field [{}] is null, cannot process it.
• missing field [{}] when calculating fingerprint
• field [{}] is null, cannot process it.
• Unmatched quote

AI-assisted analysis of elastic/elasticsearch@db6a809a66 (2026-08-12). Data as JSON: /api/errors/62436c08ef0b868d. Report an issue: GitHub.