Protobuf Schema Parser

Protobuf Schema Parser is a pure-Python library that parses and writes Protobuf schemas to and from an abstract syntax tree (AST).

The library uses proto_schema_parser.parser.Parser to parse the CST into an AST. The proto_schema_parser.generator.Generator class converts the AST back into a CST (a Protobuf schema string).

The lexer and parser are autogenerated from Buf's ANTLR lexer and parser grammar files.

Features

✅ proto2 and proto3 support
✅ message, field, enum, optional, required, repeated
✅ import, package, oneof, map, and option
✅ group and extend (in proto2)
✅ service, rpc, and stream
✅ line and block comment preservation

Installation

Install the package via pip:

pip install proto-schema-parser

Usage

To parse a protobuf schema, create a Parser object and call the parse method:

from proto_schema_parser.parser import Parser

text = """
syntax = "proto3";

message SearchRequest {
  string query = 1;
  int32 page_number = 2;
  int32 result_per_page = 3;
}
"""

result = Parser().parse(text)

This will return an AST object (ast.File) representing the parsed protobuf schema.

File(
  syntax='proto3',
  file_elements=[
    Message(
      name='SearchRequest',
      elements=[
        Field(
          name='query',
          number=1,
          type='string',
          cardinality=None,
          options=[]),
        Field(
          name='page_number',
          number=2,
          type='int32',
          cardinality=None,
          options=[]),
        Field(
          name='result_per_page',
          number=3,
          type='int32',
          cardinality=None,
          options=[])])])

To write the AST back to a protobuf schema, create a Generator object and call the generate method:

from proto_schema_parser.generator import Generator

proto = Generator().generate(result)

The proto variable now contains the string:

syntax = "proto3";
message SearchRequest {
  string query = 1;
  int32 page_number = 2;
  int32 result_per_page = 3;
}

Contributing

I welcome contributions!

Submit a PR and I'll review it as soon as I can.
Open an issue if you find a bug or have a feature request.

License