The plugin
Important message
This section will use Golang. If you are not confident about using Golang, I would still encourage you to try and get a sense of what is going on. The best alternative to write such a plugin is C++, although it is a less beginner-friendly language.
Let us start creating our own protoc plugin. Since the protogen API (https://pkg.go.dev/google.golang.org/protobuf/compiler/protogen) is easy to use, we are going to build it in Golang. Similarly to the work we did in Chapter 7, we are going to separate the business logic (pkg) and the CLI (cmd) part of our application. So, we will have the following file structure:
. ├─ cmd │ └─ protoc-gen-check │ └─ ... ├─ go.mod ├─ pkg │ └─ protoc-gen-check │ └─ ... └─ proto └─ validate ...
