Migrate to Den

Start Small

Den can be adopted incrementally. You don’t need to rewrite your entire configuration — start by adding one Den-managed host alongside your existing setup.

From Flake-Parts Dendritic

If you’re already using flake.modules, migration is direct:

# Before (flake-parts dendritic)
flake.modules.nixos.desktop = { ... };
flake.modules.homeManager.games = { ... };

# After (Den)
den.aspects.desktop.nixos = { ... };
den.aspects.games.homeManager = { ... };

Import Existing Modules

You don’t need to convert all modules. Import them directly:

{ inputs, ... }: {
  den.aspects.desktop.nixos.imports = [
    inputs.disko.nixosModules.disko
    inputs.self.modules.nixos.desktop  # existing module
  ];
}

Mix Den with Existing nixosSystem

Use mainModule to integrate Den into existing configurations:

let
  denCfg = (lib.evalModules {
    modules = [ (import-tree ./modules) ];
    specialArgs = { inherit inputs; };
  }).config;
in
  lib.nixosSystem {
    modules = [
      ./hardware-configuration.nix  # your existing modules
      ./networking.nix
      denCfg.den.hosts.x86_64-linux.igloo.mainModule  # Den modules
    ];
  }

Use import-tree for Gradual Migration

The import-tree battery auto-imports files by class directory:

non-dendritic/
  hosts/
    my-laptop/
      _nixos/
        hardware.nix
        networking.nix
      _homeManager/
        shell.nix

den.ctx.host.includes = [
  (den._.import-tree._.host ./non-dendritic/hosts)
];

Files in _nixos/ import as NixOS modules, _homeManager/ as HM modules.

Access Den Configurations Directly

Den’s outputs are standard Nix configurations:

# These are normal nixosSystem / homeManagerConfiguration results
config.flake.nixosConfigurations.igloo
config.flake.homeConfigurations.tux

Expose them directly in your flake outputs alongside existing ones.

Recommended Migration Path

1. Add Den inputs to your flake
2. Create a modules/ directory with hosts.nix
3. Add one host with den.hosts
4. Move one aspect at a time from existing modules
5. Use import-tree for files you haven’t converted yet
6. Gradually expand Den-managed aspects