Implementation:Datahub project Datahub ProtobufMessage

Knowledge Sources	Datahub_project_Datahub
Domains	Protobuf_Integration, Schema_Modeling
Last Updated	2026-02-10 00:00 GMT

Overview

Description

ProtobufMessage is a model class that represents a Protocol Buffer message type within the DataHub protobuf schema integration. It implements the ProtobufElement interface, providing methods for name resolution, type mapping, and visitor pattern support. The class wraps a DescriptorProto along with optional parent message and file descriptor context.

Key behaviors include:

• Name resolution -- Constructs a fully qualified name from the file package, optional parent message name, and the message name.
• Type mapping -- Maps protobuf messages to DataHub SchemaFieldDataType, distinguishing between MapFieldEntry (mapped to MapType) and regular messages (mapped to RecordType).
• Version extraction -- Parses the major version from the file path by looking for v<number> path segments (defaults to 1).
• Comment extraction -- Delegates to ProtobufUtils.collapseLocationComments for source code comments.

Usage

Used as a node in the ProtobufGraph that represents the protobuf schema structure. Visited by various ProtobufModelVisitor implementations to produce DataHub metadata.

Code Reference

Source Location

metadata-integration/java/datahub-protobuf/src/main/java/datahub/protobuf/model/ProtobufMessage.java

Signature

@Builder
@AllArgsConstructor
public class ProtobufMessage implements ProtobufElement {

    public String name()
    public String fullName()
    public String nativeType()
    public String fieldPathType()
    public FileDescriptorProto fileProto()
    public DescriptorProto messageProto()
    public SchemaFieldDataType schemaFieldDataType()
    public int majorVersion()
    public String comment()
    public <T> Stream<T> accept(ProtobufModelVisitor<T> visitor, VisitContext context)
}

Import

import datahub.protobuf.model.ProtobufMessage;

I/O Contract

Inputs

Parameter	Type	Description
messageProto	DescriptorProto	The protobuf message descriptor
parentMessageProto	DescriptorProto (nullable)	Parent message descriptor if this is a nested message
fileProto	FileDescriptorProto	The file descriptor containing the message

Outputs

Method	Return Type	Description
name()	String	Simple message name
fullName()	String	Fully qualified name (package.parent.name or package.name)
nativeType()	String	Same as fullName
fieldPathType()	String	Formatted as [type=fully_qualified_name] with dots replaced by underscores
schemaFieldDataType()	SchemaFieldDataType	MapType for MapFieldEntry, RecordType otherwise
majorVersion()	int	Major version number extracted from the file path

Usage Examples

ProtobufMessage msg = ProtobufMessage.builder()
    .messageProto(descriptorProto)
    .parentMessageProto(null)
    .fileProto(fileDescriptorProto)
    .build();

String fullName = msg.fullName();          // e.g., "com.example.MyMessage"
String pathType = msg.fieldPathType();     // e.g., "[type=com_example_MyMessage]"
SchemaFieldDataType dataType = msg.schemaFieldDataType();
int version = msg.majorVersion();          // e.g., 2 for path "com/example/v2/schema.proto"

Related Pages

• Implementation:Datahub_project_Datahub_ProtobufDescriptorUtils -- Used for comment collapsing and option extraction
• Implementation:Datahub_project_Datahub_ProtobufOneOfField -- Subclass-adjacent model for oneof fields that references ProtobufMessage
• Implementation:Datahub_project_Datahub_ProtobufDatasetVisitor -- Visitor that processes ProtobufMessage instances