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Nix Flake Templates

Using nix-systems

For some reasons, you might want to limit the target systems of your flake. Most templates use lib.systems.flakeExposed from nixpkgs to specify the target systems, but your Nix packages may not be supported on some of the systems. It would be possible to explicitly list the target systems in your flake, but that can be a restriction to its consumers.

With nix-systems, you can specify the default target systems, while allowing users to override the setting at their discretion.

To use nix-systems, follow these steps:

  1. Add systems input to your flake.nix:

      inputs = {
        ...
    +   systems.url = "github:nix-systems/default";
      };

  2. Make systems input visible in the outputs scope in the flake.nix:

    outputs = { nixpkgs, ... }:
    outputs = { nixpkgs, systems, ... }:

  3. Replace nixpkgs.lib.systems.flakeExposed with (import systems):

    eachSystem =
      f:
      nixpkgs.lib.genAttrs nixpkgs.lib.systems.flakeExposed (system: f nixpkgs.legacyPackages.${system});
      nixpkgs.lib.genAttrs (import systems) (system: f nixpkgs.legacyPackages.${system});