singularity-flake

A Nix Flake to use the in development singularity desktop.

Usage

# Run the packaged Singularity Desktop binary directly without installing.
# This is useful for quick experiments, but it is not a full display-manager
# session.
nix run github:mateoalfaro/singularity-flake

# Build the package
nix build github:mateoalfaro/singularity-flake

NixOS module

For a real desktop session, use the NixOS module. Add the flake to your inputs and enable it with a single option:

{
  inputs.singularity-desktop.url = "github:mateoalfaro/singularity-flake";

  outputs = { self, nixpkgs, singularity-desktop, ... }: {
    nixosConfigurations.myhost = nixpkgs.lib.nixosSystem {
      system = "x86_64-linux";
      modules = [
        singularity-desktop.nixosModules.default
      ];
    };
  };
}

Configuration

{
  programs.singularity-desktop = {
    enable = true;

    # Optional: you can also exclude bundled applications from the system profile.
    excludePackages = with pkgs; [
      singularity-calculator
      singularity-music
      singularity-store
    ];

    # Or remove every bundled app at once without listing them:
    core-apps.enable = false;

    greeter = {
      enable = true;   # enables the Singularity greeter via greetd (disabled by default)
      #You can also customize greetd by replacing the default background image
      #background = "/path/to/image.jpg";
    };

  };

  # The Singularity Cachix binary cache is enabled by default. Set this to
  # false if you do not want to use or trust it.
  # singularity-flake.cache.enable = false;
}

Importing the Singularity NixOS module enables the project's Cachix binary cache by default. To opt out, set singularity-flake.cache.enable = false. The cache setting is independent of programs.singularity-desktop.enable.

programs.singularity-desktop.excludePackages accepts package values, like environment.gnome.excludePackages. Importing the Singularity NixOS module adds an overlay that exposes these default applications under pkgs:

• singularity-files
• singularity-calculator
• singularity-calendar
• singularity-edit
• singularity-git
• singularity-leafs
• singularity-monitor
• singularity-music
• singularity-photos
• singularity-store
• singularity-videos
• singularity-write

programs.singularity-desktop.core-apps.enable (default true): setting it to false drops every extra bundled application from the system profile by default.

The desktop session, shell, greeter, portal, themes, wallpapers, and other required desktop infrastructure are kept in the core package and cannot be excluded.

When programs.singularity-desktop.greeter.enable = true, your desktop session is started by greetd on tty1. If you later switch to another display manager such as GDM with nixos-rebuild switch while still logged into that session, the existing greetd session will still be present in tty1/tty2. Reboot for the old session to disappear. This appears to be intended greetd behavior and cannot be fixed by this flake.

For display manager changes such as greetd <-> gdm, prefer one of these:

• use nixos-rebuild boot and reboot
• run nixos-rebuild switch from another TTY or over SSH
• after switching, move to the VT where the new display manager started (commonly Ctrl+Alt+F2 or Ctrl+Alt+F3)

Custom package requirements

programs.singularity-desktop.package can be overridden, but the replacement package must provide the same runtime interface as the default package:

• bin/singularity-labwc-session
• bin/singularity-desktop-session
• bin/labwc
• the greeter executables used by the module
• Wayland session metadata under share/wayland-sessions
• xdg-desktop-portal metadata and services, including a desktop-specific config at share/xdg-desktop-portal/<desktop>-portals.conf
• passthru.providedSessions

The portal configuration must be scoped to the package's desktop name. The module installs the package as an additional portal implementation and uses a low-priority xdg.portal.configPackages entry, so GNOME, KDE, Hyprland, Niri, and other desktop modules can retain their own portal configuration when they are used instead of Singularity. A replacement package must not provide a generic share/xdg-desktop-portal/portals.conf that changes portal selection for every desktop.

Inputs

• nixpkgs — pinned to nixos-unstable.
• labwc-src — tracks the latest commit of singularityos-lab/labwc.
• singularity-desktop-src — tracks the latest commit of singularityos-lab/singularity-desktop (with submodules).

Updating inputs

To update inputs manually:

nix flake update