Aug 27, 2024 3 min read

Rust Nix flake for Mac

I have a working Nix flake that I use to have a Rust dev environment for Linux, but doesn't work with Mac. If I run cargo install rustlings I get compile errors like:

  = note: ld: framework not found CoreServices
          clang-16: error: linker command failed with exit code 1 (use -v to see invocation)

and like:

  = note: ld: framework not found CoreServices
          clang-16: error: linker command failed with exit code 1 (use -v to see invocation)

💡 There are some mac-specific (and darwin) libraries that need to be present it would seem.

My working Rust nix.flake

I'm sure it could be leaner (I'm working off my Linux flake that I used for a project):

{
  inputs = {
    flake-utils.url = "github:numtide/flake-utils";
    naersk.url = "github:nix-community/naersk";
    nixpkgs.url = "github:NixOS/nixpkgs/nixpkgs-unstable";
    fenix.url = "github:nix-community/fenix";
  };

  outputs = {
    self,
    flake-utils,
    naersk,
    nixpkgs,
    fenix,
  }:
    flake-utils.lib.eachDefaultSystem (
      system: let
        pkgs = (import nixpkgs) {
          inherit system;
          overlays = [fenix.overlays.default];
        };

        PKG_CONFIG_PATH = "${pkgs.openssl.dev}/lib/pkgconfig";

        naersk' = pkgs.callPackage naersk {};
      in rec {
        defaultPackage = naersk'.buildPackage {
          src = ./.;
        };

        inherit (pkgs.lib) optionals;
        inherit (pkgs.stdenv) isDarwin;
        inherit (pkgs.darwin.apple_sdk.frameworks);

        devShell = pkgs.mkShell {
          buildInputs = [
            pkgs.openssl
            pkgs.pkg-config
          ] ++ optionals pkgs.stdenv.isDarwin [
            # Additional darwin specific inputs can be set here
            pkgs.libiconv
            pkgs.darwin.apple_sdk.frameworks.SystemConfiguration
          ] ++ (with pkgs.darwin.apple_sdk; [
            frameworks.CoreFoundation
            frameworks.CoreServices
            frameworks.SystemConfiguration
          ])
;
          env = {
            PKG_CONFIG_PATH = PKG_CONFIG_PATH;
          };
          nativeBuildInputs = with pkgs; [
            alejandra
            rust-analyzer
            (pkgs.fenix.stable.withComponents [
              "cargo"
              "clippy"
              "rust-src"
              "rustc"
              "rustfmt"
            ])
            openssl
          ];
        };
      }
    );
}

full flake.nix file that I'm using for mac

The Mac specific lines I had to add were:

        inherit (pkgs.lib) optionals;
        inherit (pkgs.stdenv) isDarwin;
        inherit (pkgs.darwin.apple_sdk.frameworks);

mac specific packages

and

++ optionals pkgs.stdenv.isDarwin [
            # Additional darwin specific inputs can be set here
            pkgs.libiconv
            pkgs.darwin.apple_sdk.frameworks.SystemConfiguration
          ] ++ (with pkgs.darwin.apple_sdk; [
            frameworks.CoreFoundation
            frameworks.CoreServices
            frameworks.SystemConfiguration
          ])

mac specific libraries

I use direnv so I have a .envrc file in the same folder that simply looks like:

use flake

.envrc

and then run direnv allow

Every time you cd into the folder, it runs the nix.flake and you have your Rust environment!

My working Rust nix.flake

Some helpful references