Use Batteries

Source

modules/aspects/batteries/

What are Batteries

Batteries are reusable aspects shipped with Den under den.batteries.* (the option is also aliased as den.provides.* and den._.*). They handle common cross-platform configuration patterns so you do not have to rewrite them.

Available Batteries

den.batteries.define-user

Creates OS and home-level user account definitions:

den.default.includes = [ den.batteries.define-user ];

Sets users.users.<name> on NixOS/Darwin and home.username/home.homeDirectory for Home Manager. Works in both host-user and standalone home contexts.

den.batteries.hostname

Sets the system hostname as defined in den.hosts.<name>.hostName:

den.default.includes = [ den.batteries.hostname ];

Mutual providers (hosts and users configuring each other)

Hosts and users can contribute configuration to each other through the aspect’s provides namespace (aliased _). This routing is built into the pipeline — no battery is required.

# host contributes to ALL its users
den.aspects.my-host.provides.to-users.homeManager = { ... };

# user contributes to ALL hosts it lives on
den.aspects.my-user.provides.to-hosts.nixos = { ... };

A tux user providing config to the specific host igloo:

den.aspects.tux = {
  provides.igloo.nixos.programs.nh.enable = true;
};

A host providing config to the specific user alice:

den.aspects.igloo = {
  provides.alice.homeManager.programs.helix.enable = true;
};

A named target (provides.igloo, provides.alice) only fires when the matching host or user is in scope, so the value can be a plain attrset. See Host<->User Mutual Providers for the full mechanism.

Note

den.batteries.mutual-provider is an inert compatibility shim — cross-entity routing is now built in, so including it has no effect.

den.batteries.primary-user

Marks a user as the primary user of the system:

den.aspects.alice.includes = [ den.batteries.primary-user ];

• NixOS: adds wheel and networkmanager groups, sets isNormalUser.
• Darwin: sets system.primaryUser.
• WSL: sets defaultUser (if WSL is enabled).

den.batteries.user-shell

Sets the default login shell at both OS and Home Manager levels:

den.aspects.alice.includes = [ (den.batteries.user-shell "fish") ];

Enables programs.<shell>.enable on the OS and in Home Manager, and sets users.users.<name>.shell.

den.batteries.forward

Creates custom Nix classes by forwarding module contents into target submodule paths. See Custom Nix Classes for details.

den.batteries.import-tree

Recursively imports plain .nix files, auto-detecting class from directory names (_nixos/, _darwin/, _homeManager/):

# Import per host (loads ./hosts/<host>/_nixos, etc.)
den.schema.host.includes = [ (den.batteries.import-tree.provides.host ./hosts) ];

# Import per user (loads ./users/<user>/_homeManager, etc.)
den.schema.user.includes = [ (den.batteries.import-tree.provides.user ./users) ];

# Import for a specific aspect
den.aspects.laptop.includes = [ (den.batteries.import-tree ./disko) ];

Requires inputs.import-tree.

den.batteries.unfree

Enables specific unfree packages by name:

den.aspects.laptop.includes = [
  (den.batteries.unfree [ "nvidia-x11" "steam" ])
];

Works for any class (nixos, darwin, homeManager). The unfree predicate builder is automatically included via den.default.

den.batteries.insecure

Enables specific insecure packages by name:

den.aspects.laptop.includes = [
  (den.batteries.insecure [ "foo-1.2.3" ])
];

Works for any class (nixos, darwin, homeManager). The insecure predicate builder is automatically included via den.default.

den.batteries.tty-autologin

Enables automatic TTY1 login on NixOS:

den.aspects.laptop.includes = [ (den.batteries.tty-autologin "alice") ];

den.batteries.vm-autologin

Enables automatic TTY1 login on NixOS VMs:

den.aspects.laptop.includes = [ (den.batteries.vm-autologin "alice") ];

den.batteries.inputs'

Provides flake-parts inputs' (system-specialized inputs) as a module argument:

den.default.includes = [ den.batteries.inputs' ];

Requires flake-parts. Works in host, user, and home contexts.

den.batteries.self'

Provides flake-parts self' (system-specialized self) as a module argument:

den.default.includes = [ den.batteries.self' ];

Requires flake-parts. Works in host, user, and home contexts.

Usage Patterns

Global Batteries

Apply to all entities via den.default:

den.default.includes = [
  den.batteries.define-user
  den.batteries.inputs'
];

Per-Aspect Batteries

Apply to specific aspects:

den.aspects.alice.includes = [
  den.batteries.primary-user
  (den.batteries.user-shell "zsh")
  (den.batteries.unfree [ "vscode" ])
];

Battery Composition

Batteries compose with regular aspects:

den.aspects.my-admin = {
  includes = [
    den.batteries.primary-user
    (den.batteries.user-shell "fish")
    { nixos.security.sudo.wheelNeedsPassword = false; }
  ];
};