nixos-server/flake.nix

{
  inputs = {
    # get pinned version of nixpkgs. update with `nix flake update nixpkgs` or `nix flake update` for all inputs
    nixpkgs.url = "github:nixos/nixpkgs/nixos-unstable";

    # home manager
    home-manager = {
      url = "github:nix-community/home-manager";
      inputs.nixpkgs.follows = "nixpkgs";
    };

    nix-index-database = {
      url = "github:nix-community/nix-index-database";
      inputs.nixpkgs.follows = "nixpkgs";
    };
  };
  outputs =
    { self, nixpkgs, ... }@inputs:
    {
      # configuration name matches hostname, so this system is chosen by default
      nixosConfigurations.nixos = nixpkgs.lib.nixosSystem {
        # pass along all the inputs and stuff to the system function
        specialArgs = { inherit inputs; };
        modules = [
          # import configuration
          ./configuration.nix

          # home manager part 2
          inputs.home-manager.nixosModules.default

          inputs.nix-index-database.nixosModules.nix-index

          { programs.nix-index-database.comma.enable = true; }
        ];
      };
    };
}