registry

This Nix module configures a flake registry entry named dotfiles that points to the /etc/nixos directory. It’s designed to make your dotfiles flake easily accessible by Nix commands. This is especially useful when managing a NixOS system configuration with dotfiles stored within the /etc/nixos directory. It also configures the NIX_PATH environment variable to include an entry for ‘dotfiles’, ensuring that older Nix commands can also locate your configuration.

Options

local.registry.enable

Type: boolean

Default: false

Description: Enables or disables the flake registry configuration for dotfiles. When enabled, it creates a registry entry named dotfiles and configures NIX_PATH.

Details

This module performs the following actions when local.registry.enable is set to true:

1. Flake Registry Entry: Creates a flake registry entry named dotfiles.

   • from: Specifies that the entry is an “indirect” entry identified by the id dotfiles.
   • to: Specifies that the entry resolves to a path type, specifically /etc/nixos. This is where your dotfiles flake (presumably containing your NixOS configuration) should reside.

   In effect, running nix flake show dotfiles will resolve to the contents of /etc/nixos as if it were a flake.

2. NIX_PATH Configuration: Adds a dotfiles=/etc/nixos entry to the nix.nixPath. This is important for older Nix commands (those that predate full flake support) that rely on the NIX_PATH environment variable to locate Nix expressions. This ensures that your dotfiles configuration is accessible even when using older tools. This means you can, for example, use nix-build '<dotfiles>' to build the default output of the flake in /etc/nixos.

3. nixpkgs Entry: Includes nixpkgs=/nix/var/nix/profiles/per-user/root/channels/nixpkgs in nix.nixPath. This is crucial for resolving dependencies and ensuring that the correct Nix packages are available. Note that this path is dependent on how nixpkgs is installed on the system, and this value is a very common default.

Usage Example

To enable this module and make your dotfiles accessible, add the following to your configuration.nix:

{ config, pkgs, ... }:

{
  imports =
    [ # Include other modules here
    ];

  local.registry.enable = true;

  # ... other configuration ...
}

After rebuilding your system with nixos-rebuild switch, you can then use commands like:

• nix flake show dotfiles - Inspect the flake located in /etc/nixos.
• nix build dotfiles#nixosConfigurations.my-system.config.system.build.toplevel - build your system using flakes.
• nix-build '<dotfiles>' - Build the default output of the flake (if defined).