.. _sec-importing-modules:

Importing Modules
~~~~~~~~~~~~~~~~~

Sometimes NixOS modules need to be used in configuration but exist outside of
Nixpkgs. These modules can be imported:

::

    { config, lib, pkgs, ... }:

    {
      imports =
        [ # Use a locally-available module definition in
          # ./example-module/default.nix
            ./example-module
        ];

      services.exampleModule.enable = true;
    }

The environment variable ``NIXOS_EXTRA_MODULE_PATH`` is an
absolute path to a NixOS module that is included alongside the Nixpkgs NixOS
modules. Like any NixOS module, this module can import additional modules:

::

    # ./module-list/default.nix
    [
      ./example-module1
      ./example-module2
    ]

::

    # ./extra-module/default.nix
    { imports = import ./module-list.nix; }

::

    # NIXOS_EXTRA_MODULE_PATH=/absolute/path/to/extra-module
    { config, lib, pkgs, ... }:

    {
      # No `imports` needed

      services.exampleModule1.enable = true;
    }