Declarative flatpak manager for NixOS inspired by declarative-flatpak and nix-darwin's homebrew module. NixOs and home-manager modules are provided for system wide or user flatpaks installation.

This repository contains experimental code inspired by Martin Wimpress' Blending NixOS with Flathub for friends and family talk at NixCon 2023. I like the idea of managing applications the say way I do with homebrew on nix-darwin.

nix-flatpak follows a convergent mode approach to package management (described in this thread): the target system state description is not exhaustive, and there's room for divergence across builds and rollbacks. For a number of desktop application I want to be able to track the lastet version, or allow them to auto update. For such applications, a convergent approach is a reasonable tradeoff wrt system reproducibility. YMMV.

Flatpak applications are installed by systemd oneshot service triggered at system activation. Depending on the number of applications to install, this could increase activation time significantly.

This project is released as a flake. Releases are tagged with semantic versioning. Versions below 1.0.0 are considered early, development, releases. Users can track a version by passing its tag as ref

...
nix-flatpak.url = "github:gmodena/nix-flatpak/?ref=v0.1.0";
...

The main branch is considered unstable, and might break installs.

Enable flatpak in configuration.nix:

services.flatpak.enable = true;

Import the module (nixosModules.nix-flatpak or homeManagerModules.nix-flatpak). Using flake, installing nix-flatpak as a NixOs module would looks something like this:

{
  inputs = {
    # ...
    nix-flatpak.url = "github:gmodena/nix-flatpak/main"; # unstable branch. Use github:gmodena/nix-flatpak/?ref=<tag> to pin releases.
  };

  outputs = { nix-flatpak, ... }: {
    nixosConfigurations.<host> = nixpkgs.lib.nixosSystem {
      modules = [
        nix-flatpak.nixosModules.nix-flatpak

        ./configuration.nix
      ];
    };
  };
}

Depending on how config and inputs are derived homeManagerModules import can be flaky. Here's an example of how homeManagerModules is imported on my nixos systems config in modules/home-manager/desktop/nixos/default.nix. flake-inputs is a special extra arg set in the repo flake.nix [mkNixosConfiguration](https://github.com/gmodena/config/blob/main/flake.nix#L29.

By default nix-flatpak will add the flathub remote. Remotes can be manually configured via the services.flatpak.remotes option:

services.flatpak.remotes = [{ name = "flathub-beta"; location = "https://flathub.org/beta-repo/flathub-beta.flatpakrepo"; }];

Declare packages to install with:

  services.flatpak.packages = [
    { appId = "com.brave.Browser"; origin = "flathub";  }
    "com.obsproject.Studio"
    "im.riot.Riot"
  ];

You can pin a specific commit setting commit=<hash> attribute.

Rebuild your system (or home-manager) for changes to take place.

Set

services.flatpak.update.onActivation = true;

to enable updates at system activation. The default is false so that repeated invocations of nixos-rebuild switch are idempotent. Applications pinned to a specific commit hash will not be updated.

Periodic updates can be enabled by setting:

services.flatpak.update = {
  auto = {
    enable = true;
    onCalendar = "weekly"; # Default value
  };
};

Auto updates trigger on system activation.

Under the hood, updates are scheduled by realtime systemd timers. onCalendar accepts systemd's update.auto.OnCalendar expressions. Timers are persisted across sleep / resume cycles. See https://wiki.archlinux.org/title/systemd/Timers for more information.

Flatpaks are stored out of nix store at /var/lib/flatpak and ${HOME}/.local/share/flatpak/ for system (nixosModules) and user (homeManagerModules) installation respectively. Flatpaks isntallation are not generational: upon a system rebuild and rollbacks, changes in packages declaration will result in downloading applications anew.

Keeping flatpaks and nix store orthogonal is an explicit design choice, dictate by my use cases:

1. I want to track the latest version of all installed applications.
2. I am happy to trade network for storage.

YMMV.

If you need generational builds, declarative-flatpak might be a better fit.