I’m developing some features for GitHub - elixir-protobuf/protobuf: A pure Elixir implementation of Google Protobuf. · GitHub, but I need a way to know what modules are protobuf modules and even want to store more information for them

A protobuf module is defined like this

defmodule Foo do
  use Protobuf, syntax: :proto3
end

defmodule Bar do
  use Protobuf, syntax: :proto3
end

I want to get the information in runtime/compile time like

> Protobuf.all_messages
[
  {Foo, some_foo_metadata},
  {Bar, some_bar_metadata}
]

Is there any way to achieve this?

A direct way I can think of is to define a function for each protobuf module, and call them when the program starts. I can use ets or persistent_term to build “all_messages”. But I can’t find a callback like this.

I don’t know if this can be implemented in compiling time, but it seems hard because we can’t make sure every protobuf module is compiled every time.