elastic/elasticsearch · error · IllegalArgumentException

unable to convert [ ] to integer

Error message

unable to convert [{}] to integer

What it means

ConvertProcessor.Type.INTEGER.convert calls Integer.parseInt (or Integer.decode for '0x' / '-0x' prefixes) on value.toString(); a NumberFormatException is wrapped as IllegalArgumentException. The original value (via toString) is in the message. Thrown from ConvertProcessor.execute for both scalar and list values.

Solutions

1. If the value is decimal, convert via a two-step: type: double then a script to cast, or pre-round.
2. Strip currency symbols, whitespace, and thousands separators before the convert processor.
3. Set ignore_missing: true if the field is sometimes absent, or filter empty strings upstream.
4. Use on_failure to quarantine unconvertible values.

Example fix

// before — decimal string cannot be parsed as integer
//   { "convert": { "field": "count", "type": "integer" } }  // count = "1.5"
//
// after — accept decimal, then truncate via script
//   { "convert": { "field": "count", "type": "double" } },
//   { "script": { "source": "ctx.count = (int) ctx.count" } }

boolean isParsableAsInteger(Object v) {
    if (v == null) return false;
    String s = v.toString();
    try { Integer.decode(s); return true; } catch (NumberFormatException ignored) {}
    try { Integer.parseInt(s); return true; } catch (NumberFormatException ignored) {}
    return false;
}

static boolean isIntegerLike(Object v) {
    if (v instanceof Number n) return n.intValue() == n.doubleValue();
    if (v instanceof String s) return s.matches("[+-]?(?:0[xX][0-9A-Fa-f]+|\\d+)");
    return false;
}

{
  "convert": {
    "field": "count", "type": "integer",
    "on_failure": [
      { "set": { "field": "ingest.error", "value": "convert-int" } },
      { "redirect": { "pipeline": "quarantine" } }
    ]
  }
}

When it happens

Trigger: convert processor with type: integer on a value that is not parseable: 'abc', '1.5' (Integer.parseInt rejects decimal), 'true', empty string '', '0xZZ'. Hex values must be valid Integer.decode input. Multi-valued fields fail on the first unparseable element.

Common situations: Source field contains decimal numbers ('1.0') the user expected to convert to integer; quoted numeric strings with currency symbols; locale-specific number formats; empty strings from sparse data.

Related errors

• unable to convert [ ] to double
• unable to convert [ ] to long
• cannot convert object of type
• CEF extensions contain unescaped equals sign
• Illegal escape sequence '\

AI-assisted analysis of elastic/elasticsearch@db6a809a66 (2026-08-12). Data as JSON: /api/errors/2f0d1373b2c135a6. Report an issue: GitHub.

Appendix: source

Thrown at modules/ingest-common/src/main/java/org/elasticsearch/ingest/common/ConvertProcessor.java:43

/**
 * Processor that converts fields content to a different type. Supported types are: integer, float, boolean and string.
 * Throws exception if the field is not there or the conversion fails.
 */
public final class ConvertProcessor extends AbstractProcessor {

    enum Type {
        INTEGER {
            @Override
            public Object convert(Object value) {
                try {
                    String strValue = value.toString();
                    if (strValue.startsWith("0x") || strValue.startsWith("-0x")) {
                        return Integer.decode(strValue);
                    }
                    return Integer.parseInt(strValue);
                } catch (NumberFormatException e) {
                    throw new IllegalArgumentException("unable to convert [" + value + "] to integer", e);
                }

            }
        },
        LONG {
            @Override
            public Object convert(Object value) {
                try {
                    String strValue = value.toString();
                    if (strValue.startsWith("0x") || strValue.startsWith("-0x")) {
                        return Long.decode(strValue);
                    }
                    return Long.parseLong(strValue);
                } catch (NumberFormatException e) {
                    throw new IllegalArgumentException("unable to convert [" + value + "] to long", e);
                }
            }
        },

View on GitHub (pinned to db6a809a66)