I have a monorepo/umbrella project that the complete source code can be found on my github repo.

There I have currently four child application, which they’re most independent from each other. I would like to know how I could build each one separately with nix.

For example, if I want ot build a single common mix project with nix (a library in this case) we can use the buildMix helper function:

# flake example
# inside `outputs`
{
  packages.${system}.default = beam-pkgs.buildMix {
    name = “my-package”;
    src = ./.;
    version = “0.1.0”;
    beamDeps = [] #… use mix2nix or mixFodDeps
  };
}

however for an umbrella, will you need to copy also the parent one? trying to use the above function passing src as ./apps/child gives errors as the child app can’t find dependencies path… removing these lines from the children MixProject makes the child app build successfully:

      build_path: "../../_build",
      deps_path: "../../deps",
      lockfile: "../../mix.lock",