[[ch-nix-flakes]] == Nix Flakes :nixos-wiki-flakes: https://nixos.wiki/wiki/Flakes Home Manager includes a `flake.nix` file for compatibility with {nixos-wiki-flakes}[Nix Flakes]. The support is still experimental and may change in backwards incompatible ways. [[sec-flakes-prerequisties]] === Prerequisties * Install Nix 2.4 or have it in `nix-shell`. * Enable experimental features `nix-command` and `flakes`. + Either set in `nix.conf` + [source,bash] experimental-features = nix-command flakes + or pass them to `nix` and `home-manager` by + [source,console] ---- $ nix --extra-experimental-features "nix-command flakes" $ home-manager --extra-experimental-features "nix-command flakes" ---- * Prepare your Home Manager configuration (`home.nix`). + Unlike the channel-based setup, `home.nix` will be evaluated when the flake is built, so it must be present before bootstrap of Home Manager from the flake. See <> for introduction about writing a Home Manager configuration. + [NOTE] ==== The `stateVersion` will be specified in the flake instead of in the configuration file. Remove the line containing `home.stateVersion` in the example. ==== [[sec-flakes-standalone]] === Standalone setup 1. Set up a flake with a `flake.nix` as follows: + [source,nix] ---- { description = "Home Manager configuration of Jane Doe"; inputs = { # Specify the source of Home Manager and Nixpkgs home-manager.url = "github:nix-community/home-manager"; nixpkgs.url = "github:nixos/nixpkgs/nixos-unstable"; home-manager.inputs.nixpkgs.follows = "nixpkgs"; }; outputs = { home-manager, ... }: let system = "x86_64-linux"; username = "jdoe"; in { homeConfigurations.${username} = home-manager.lib.homeManagerConfiguration { # Specify the path to your home configuration here configuration = import ./home.nix; inherit system username; homeDirectory = "/home/${username}"; # Update the state version as needed. # See the changelog here: # https://nix-community.github.io/home-manager/release-notes.html#sec-release-21.05 stateVersion = "22.05"; # Optionally use extraSpecialArgs # to pass through arguments to home.nix }; }; } ---- + [NOTE] ==== * The above example tracks the master branch of Home Manager and nixos-unstable branch of Nixpkgs. If you would like to use the `release-22.05` branch, change the `home-manager` input url to `github:nix-community/home-manager/release-22.05` and `nixpkgs` url to `github:NixOS/nixpkgs/nixos-22.05`. Make sure to also update to the `stateVersion` option accordingly. * The Home Manager library is exported by the flake under `lib.hm`. ==== 2. Install Home Manager and apply the configuration by + [source,console] ---- $ nix build --no-link #homeConfigurations.jdoe.activationPackage $ "$(nix path-info #homeConfigurations.jdoe.activationPackage)"/activate ---- + Substitute `` with the flake URI of the configuration flake. If `flake.nix` resides in `~/.config/nixpkgs`, `` may be `~/.config/nixpkgs` as a Git tree or `path:~/.config/nixpkgs` if not. 3. Since the release `21.05`, building a flake-based configuration is as simple as + [source,console] $ home-manager switch --flake '#jdoe' + once home-manager is installed. + Here, `jdoe` is a configuration specified in the flake file, and `#jdoe` will be expanded to `#homeConfigurations.jdoe.activationPackage` and be built by Nix. [NOTE] ==== The flake inputs are not upgraded automatically when switching. The analogy to the command `home-manager --update ...` is `nix flake update`. If updating more than one input is undesirable, the command `nix flake lock --update-input ` can be used. You can also pass flake-related options such as `--recreate-lock-file` or `--update-input [input]` to `home-manager` when building/switching, and these options will be forwarded to `nix build`. See the {nixos-wiki-flakes}[NixOS Wiki page] for detail. ==== [[sec-flakes-nixos-module]] === NixOS module To use Home Manager as a NixOS module, a bare-minimum `flake.nix` would be as follows: [source,nix] ---- { description = "NixOS configuration"; inputs = { nixpkgs.url = "github:nixos/nixpkgs/nixos-unstable"; home-manager.url = "github:nix-community/home-manager"; home-manager.inputs.nixpkgs.follows = "nixpkgs"; }; outputs = inputs@{ nixpkgs, home-manager, ... }: { nixosConfigurations = { hostname = nixpkgs.lib.nixosSystem { system = "x86_64-linux"; modules = [ ./configuration.nix home-manager.nixosModules.home-manager { home-manager.useGlobalPkgs = true; home-manager.useUserPackages = true; home-manager.users.jdoe = import ./home.nix; # Optionally, use home-manager.extraSpecialArgs to pass # arguments to home.nix } ]; }; }; }; } ---- The Home Manager configuration is then part of the NixOS configuration and is automatically rebuilt with the system when using the appropriate command for the system, such as `nixos-rebuild switch --flake `. [[sec-flakes-nix-darwin-module]] === nix-darwin module The flake-based setup of the Home Manager nix-darwin module is similar to that of NixOS. The `flake.nix` would be: [source,nix] ---- { description = "NixOS configuration"; inputs = { nixpkgs.url = "github:nixos/nixpkgs/nixos-unstable"; nix-darwin.url = "github:lnl7/nix-darwin"; darwin.inputs.nixpkgs.follows = "nixpkgs"; home-manager.url = "github:nix-community/home-manager"; home-manager.inputs.nixpkgs.follows = "nixpkgs"; }; outputs = inputs@{ nixpkgs, home-manager, nix-darwin, ... }: { darwinConfigurations = { hostname = nix-darwin.lib.darwinSystem { system = "x86_64-darwin"; modules = [ ./configuration.nix home-manager.darwinModules.home-manager { home-manager.useGlobalPkgs = true; home-manager.useUserPackages = true; home-manager.users.jdoe = import ./home.nix; # Optionally, use home-manager.extraSpecialArgs to pass # arguments to home.nix } ]; }; }; }; } ---- and it is also rebuilt with the nix-darwin generations. The rebuild command here may be `darwin-rebuild switch --flake `.