apache/beam · error · IllegalArgumentException

Unable to parse '" + s + "' as a byte value.

Error message

Unable to parse '" + s + "' as a byte value.

What it means

BytesHint.parse converts strings like '10kb', '2.5mb' into byte counts using a regex with known suffixes. If the string doesn't match the pattern or the suffix isn't recognized, Beam throws IllegalArgumentException("Unable to parse '<s>' as a byte value.").

Source

Thrown at sdks/java/core/src/main/java/org/apache/beam/sdk/transforms/resourcehints/ResourceHints.java:180

    @Override
    public int hashCode() {
      return Long.hashCode(value);
    }

    public BytesHint(long value) {
      this.value = value;
    }

    public static long parse(String s) {
      Matcher m = Pattern.compile("([\\d.]+)[\\s]?([\\D]+$)").matcher(s);
      if (m.find()) {
        String number = m.group(1);
        String suffix = m.group(2);
        if (number != null && suffix != null && suffixes.containsKey(suffix)) {
          return (long) (Double.parseDouble(number) * suffixes.get(suffix));
        }
      }
      throw new IllegalArgumentException("Unable to parse '" + s + "' as a byte value.");
    }

    @Override
    public ResourceHint mergeWithOuter(ResourceHint outer, boolean isSum) {
      return isSum
          ? new BytesHint(value + ((BytesHint) outer).value)
          : new BytesHint(Math.max(value, ((BytesHint) outer).value));
    }

    @Override
    public byte[] toBytes() {
      return String.valueOf(value).getBytes(StandardCharsets.US_ASCII);
    }
  }

  /*package*/ static class StringHint extends ResourceHint {
    private final String value;

View on GitHub (pinned to 12126d8942)

Solutions

1. Use supported suffixes exactly: e.g. '10kb', '2.5mb', '1gb' (check BytesHint suffix map)
2. Use a dot as the decimal separator ('1.5mb', not '1,5mb')
3. Remove spaces or extra characters from the value
4. If a unitless value is intended, confirm whether the parser accepts it or add the suffix explicitly

Example fix

// before
--resourceHints=min_ram_mb=10 GiB

// after
--resourceHints=min_ram_mb=10240mb

Pattern p = Pattern.compile("^([0-9]*\\.?\\d+)(kb|mb|gb)$");
for (String hint : hints) {
  String value = hint.split("=", 2)[1];
  if (!p.matcher(value).matches()) {
    throw new IllegalArgumentException("Value must look like '10mb': " + value);
  }
}

try {
  ResourceHints.fromOptions(options);
} catch (IllegalArgumentException e) {
  if (e.getMessage().contains("as a byte value")) {
    // rewrite the value using a supported suffix
  }
}

When it happens

Trigger: Passing a resource hint value like 'cpu_count=2GBx' or 'min_ram_mb=10 kilobytes' where the value fails the byte-value regex (no numeric part, unknown suffix, or both groups null/mismatched).

Common situations: Writing suffixes Beam doesn't know ('KB' vs 'kb', 'GiB'); including spaces ('10 kb'); passing plain unitless values where a suffix is required; locale-specific decimal commas ('1,5mb').

Understand the failure class

Background: "Invalid ... format", "must be in format X", "does not look like a ..." — invalid argument format errors across CLI tools and libraries — this error's family across 17 libraries.

• Parsing and encoding errors: unexpected token, malformed input — why parsers reject input and how to find the real culprit.

Related errors

• Unparsable resource hint:
• Unable to parse JSON value
• Unknown resource hint:
• Timing number 0b" + timingNumber.toString(2) + " has more th
• No proto encoding for PaneInfoCoder, always part of Windowed

AI-assisted analysis of apache/beam@12126d8942 (2026-09-13). Data as JSON: /api/errors/c333f4153e92dfb4. Report an issue: GitHub.