How to mkDerivation for a C++ project with Rust FFI?

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1

Hi there, I would like to package a private repo which is a C++ project built with CMake but has some rust code as a FFI brought in using Corrosion and cxx-rs. Im struggling to bring in the rust crate dependencies.

I have tried building from a minimal example project which i forked found here: GitHub - MattCairns/rusty_cmake: Rust cmake integration template with corrosion and cxx

cxx-rs is available in nixPkgs but im not sure if/how i could leverage that package. Any help packaging this would be much appreciated!

Here is my nix:

{ stdenv
, fetchFromGitHub
, cmake
, pkg-config
, corrosion
, cargo
, rustc
, cxx-rs
, rustPlatform
}:

stdenv.mkDerivation rec {
  pname = "rusty_cmake";
  version = "main";

  src = fetchFromGitHub {
    owner = "mattcairns";
    repo = "${pname}";
    rev = "${version}";
    hash = "sha256-g8hxq9kNn7XH8yqxlUXtBoXgV4ezLBjAHxZrVUJbCgI=";
  };

  # cargoDeps = rustPlatform.importCargoLock {
  #   lockFile = source/src/rusty_code/Cargo.lock;
  # };

  # Somehow download the cxx crate and cxx-build crates and move them to build dir?
  # cxxRustDeps = rustPlatform.fetchCargoTarball {
  #   inherit src;
  #   name = "cxx";
  #   hash = "";
  # };

  nativeBuildInputs = [
    cmake
    pkg-config
    corrosion
    cargo
    rustc
    cxx-rs
  ];

  doCheck = true;
}