Example flake with auto population from hosts dir

flake.nix

{
  inputs = { nixpkgs.url = "github:nixos/nixpkgs/nixos-unstable"; };

  outputs = { self, nixpkgs, ... }@inputs:
    let
      inherit (self) outputs;
      files = builtins.readDir ./nix_configs/hosts;
      hostnames = builtins.filter
        (name: builtins.hasAttr name files && (files.${name} == "directory"))
        (builtins.attrNames files);
      system = "x86_64-linux";
    in {
      # nixos configuration entrypoints
      nixosConfigurations = builtins.listToAttrs (map (hostname: {
        name = hostname;
        value = nixpkgs.lib.nixosSystem {
          inherit system;
          specialArgs = { inherit inputs; };
          modules = [ ./nix_configs/hosts/${hostname} ];
        };
      }) hostnames);
    };
}