[question] How to add pre-commit hooks to nixos flake configuration?

[cronyakatsuki]

Hello, I have been trying out pre-commit hooks and am interested how would I be going around adding it to my nixos flake configuration?

I have tried out this with the flake only, but get the next error:

flake.nix

{
  description = "Nixos config flake";

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

    pre-commit-hooks.url = "github:cachix/pre-commit-hooks.nix";

    flake-utils.url = "github:numtide/flake-utils";

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

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

    hb-downloader = {
      url = "git+file:///home/crony/Documents/develop/hb-downloader";
      inputs.nixpkgs.follows = "nixpkgs";
    };
  };

  outputs = inputs@{ self, nixpkgs, flake-utils, pre-commit-hooks, home-manager
    , ... }: {
      nixosConfigurations = {
        default = nixpkgs.lib.nixosSystem {
          system = "x86_64-linux";
          modules = [
            ./nixos/configuration.nix

            home-manager.nixosModules.home-manager
            {
              home-manager.useGlobalPkgs = true;
              home-manager.extraSpecialArgs = { inherit inputs; };
              home-manager.users.crony = {
                imports = [ ./home-manager/home.nix ];
              };
            }
            flake-utils.lib.eachDefaultSystem
            (system: {
              checks = {
                pre-commit-check = pre-commit-hooks.lib.${system}.run {
                  src = ./.;
                  hooks = { nixpkgs-fmt.enable = true; };
                };
              };
              devShell = nixpkgs.legacyPackages.${system}.mkShell {
                inherit (self.checks.${system}.pre-commit-check) shellHook;
              };
            })
          ];
        };
      };
    };
}

error

error:
       … while checking flake output 'nixosConfigurations'

         at /nix/store/8c26jqrhnk2iw0hynh3jr9gy7yixz819-source/flake.nix:29:7:

           28|     , ... }: {
           29|       nixosConfigurations = {
             |       ^
           30|         default = nixpkgs.lib.nixosSystem {

       … while checking the NixOS configuration 'nixosConfigurations.default'

         at /nix/store/8c26jqrhnk2iw0hynh3jr9gy7yixz819-source/flake.nix:30:9:

           29|       nixosConfigurations = {
           30|         default = nixpkgs.lib.nixosSystem {
             |         ^
           31|           system = "x86_64-linux";

       (stack trace truncated; use '--show-trace' to show the full trace)

       error: attempt to call something which is not a function but a set

       at /nix/store/na7sykizsgkzh9i3wc8m8pz5xfqib2rv-source/lib.nix:36:17:

           35|         let
           36|           ret = f system;
             |                 ^
           37|           op = attrs: key: attrs //

I'm still new to nix and flakes, so would like some help. The flake is located in my user directory.

[cronyakatsuki]

Fixed by adding a simple shell.nix and making a shell environment.