如何将 Python proto-plus 消息 class 转换为 protobuf proto 文件？

Question

I see that a lot of Google Python SDK code uses the proto-plus library to write protobuf message schemas as a Python class. I was wondering if there is a way to convert this class to a proto file.

ie.

import proto

class Composer(proto.Message):
    given_name = proto.Field(proto.STRING, number=1)
    family_name = proto.Field(proto.STRING, number=2)

class Song(proto.Message):
    composer = proto.Field(Composer, number=1)
    title = proto.Field(proto.STRING, number=2)
    lyrics = proto.Field(proto.STRING, number=3)
    year = proto.Field(proto.INT32, number=4)

and generate a proto file

Answer 1

Proto Plus does not include this functionality.

It should be possible to do this since there's a 1:1 mapping between Proto Plus, Protobuf generated sources and proto files.

But, I suspect it's an anti-pattern. It's not unlike hacking a binary and wanting to regenerate sources.

The source-of-truth for protobuf generated code is its proto files.

Google provides Proto Plus to make protoc-generated Python sources more idiomatic.

Presumably Google's build pipeline now includes a generator for Proto Plus sources directly from proto files (this may be part of the SDK or is some adjunct to protoc).

While the Proto Plus docs describe declaring messages , I think this is itself an anti-pattern and should not be encouraged as it results in protobuf code without definitive (cross-language) sources(-of-truth).