Hjem

A streamlined way to manage your $HOME for NixOS systems.

What is this?

Hjem ("home" in Danish) is a NixOS module that implements a simple and streamlined way to manage files in your $HOME, such as but not limited to files in your ~/.config.

Features

1. Multi-user by default
2. Small, simple codebase with minimal abstraction
3. Powerful $HOME management functionality and potential
4. Systemd-native file management via systemd-tmpfiles
5. Extensible for 3rd-party use

Implementation

Hjem exposes a very basic interface with multi-tenant capabilities, which you may use to manage individual users' homes by leveraging the module system.

{
  homes = {
    alice.files = {
      # Write a text file in `/homes/alice/.config/foo`
      # with the contents bar
      ".config/foo".text = "bar";
    };
  };
}

Each attribute under homes, e.g., homes.alice and homes.jane represent a user managed via users.users in NixOS. If a user does not exist, then Hjem will refuse to manage their $HOME by filtering non-existent users in file creation.

Module Interface

The interface for the homes module is conceptually very similar to Home-Manager, but it does not act as a collection of modules like Home-Manager. We only implement basic features, and leave abstraction to the user to do as they see fit.

Below is a live implementation of the module.

nix-repl> :p nixosConfigurations."nixos".config.homes
{
  alice = {
    directory = "/home/alice";
    enable = true;
    files = {
      ".config/foo" = {
        enable = true;
        executable = false;
        recursive = false;
        source = «derivation /nix/store/prc0c5yrfca63x987f2k9khpfhlfnq15-config-foo.drv»;
        target = ".config/foo";
        text = "bar";
      };
    };
    user = "alice";
  };
}

nix-repl> :p nixosConfigurations."nixos".config.systemd.user.tmpfiles.users
{
  alice = {
    rules = [ "L /home/alice/.config/foo - - - - /nix/store/jfpr2z1z1aykpw2j2gj02lwwvwv6hml4-config-foo" ];
  };
}

Instead of relying on a Bash script to link files in place, we utilize systemd-tmpfiles to ensure the files are linked in place.

Things to do

Hjem is mostly feature-complete, in the sense that it is a clean implementation of home.files in Home-Manager: it was never a goal to dive into abstracting files into modules. Although, some basic features such as managing Systemd Services or user packages may make their ways into the project in future iterations.

Manifest & Cleaning up dangling files

The systemd-tmpfiles module lacks a good way of cleaning up dangling lists, e.g., from files that are no longer linked. To tackle this problem, a manifest of files can be used to diff said manifest during switch and remove files that are no longer managed.

License

This project is made available under the GPLv3 license. See LICENSE for more details on the exact conditions.