apache/druid · error · InvalidProtocolBufferException

Invalid Value type.

Error message

Invalid Value type.

What it means

google.protobuf.Value is a oneof that must have exactly one kind set (null_value, number_value, string_value, bool_value, struct_value, list_value). Druid's converter converts a Value message to a single value; when the message has more than one field populated it is malformed, so this InvalidProtocolBufferException is thrown.

Source

Thrown at extensions-core/protobuf-extensions/src/main/java/org/apache/druid/data/input/protobuf/ProtobufConverter.java:218

        msg -> {
          final Descriptors.Descriptor descriptor = msg.getDescriptorForType();
          final Descriptors.FieldDescriptor field = descriptor.findFieldByName("fields");
          if (field == null) {
            throw new InvalidProtocolBufferException("Invalid Struct type.");
          }
          // Struct is formatted as a map object.
          return convertSingleValue(field, msg.getField(field));
        }
    );
    converters.put(
        Value.getDescriptor().getFullName(),
        msg -> {
          final Map<Descriptors.FieldDescriptor, Object> fields = msg.getAllFields();
          if (fields.isEmpty()) {
            return null;
          }
          if (fields.size() != 1) {
            throw new InvalidProtocolBufferException("Invalid Value type.");
          }
          final Map.Entry<Descriptors.FieldDescriptor, Object> entry = fields.entrySet().stream().findFirst().get();
          return convertSingleValue(entry.getKey(), entry.getValue());
        }
    );
    converters.put(
        ListValue.getDescriptor().getFullName(),
        msg -> {
          Descriptors.Descriptor descriptor = msg.getDescriptorForType();
          Descriptors.FieldDescriptor field = descriptor.findFieldByName("values");
          if (field == null) {
            throw new InvalidProtocolBufferException("Invalid ListValue type.");
          }
          return convertList(field, (List<?>) msg.getField(field));
        }
    );
    return converters;
  }

View on GitHub (pinned to 9b90983fd2)

Solutions

1. Fix the producer to set exactly one field of the Value oneof
2. Validate upstream bytes with protoc --decode before ingesting
3. Check for data corruption in the transport (Kafka topic, network) that could merge or corrupt records

Example fix

// before: producer sets two members of the Value oneof
value.setStringValue("x"); value.setBoolValue(true);
// after: set exactly one
value.setStringValue("x");

Message valueMsg = ...;
if ("google.protobuf.Value".equals(valueMsg.getDescriptorForType().getFullName())
    && valueMsg.getAllFields().size() > 1) {
  throw new IllegalStateException("google.protobuf.Value has multiple oneof members set");
}

boolean isValidValue(Message msg) {
  if (!"google.protobuf.Value".equals(msg.getDescriptorForType().getFullName())) return true;
  int n = msg.getAllFields().size();
  return n == 0 || n == 1;
}

try {
  Map<String, Object> row = ProtobufConverter.convertMessage(msg);
} catch (ParseException e) {
  log.error("Malformed Value oneof in record; fix producer or skip record", e);
  // route to DLQ instead of failing the whole read
}

When it happens

Trigger: A google.protobuf.Value message with two or more simultaneously-set oneof members is passed to ProtobufConverter.convertMessage (e.g. bytes crafted by hand or produced by a non-conformant producer); fields.size() > 1 at conversion time.

Common situations: Hand-crafted or fuzzed protobuf bytes; a buggy producer writing multiple oneof fields; binary data truncated/corrupted in transit causing malformed parse results.

Understand the failure class

Background: "cannot parse invalid wire-format data", "cannot unmarshal", "failed unmarshalling": protobuf unmarshal errors explained — this error's family across 10 libraries.

Related errors

• Invalid Wrapper type.
• Invalid Struct type.
• Invalid ListValue type.
• Protobuf message could not be parsed
• Fail to decode protobuf message!

AI-assisted analysis of apache/druid@9b90983fd2 (2026-09-07). Data as JSON: /api/errors/c3ee3101b5a91919. Report an issue: GitHub.