I've done extensive Google searching but couldn't find a good tool to do this. The closest I could find was https://github.com/googleapis/gnostic, which allows converting an OpenAPI description (swagger.yaml) into a .pb file or a .json file. I'm wondering if there are any tools to convert this .pb file into a .proto proto3 file?
I also tried https://github.com/NYTimes/openapi2proto but unfortunately there are a few cases that aren't handled correctly.
Thanks in advance for your help!