feat: declaratively install flatpak

flake.nix

@@ -24,6 +24,8 @@
       inputs.nixpkgs.follows = "nixpkgs";
     };
 
+    nix-flatpak.url = "github:gmodena/nix-flatpak";
+
     nix-homebrew = {
       url = "github:zhaofengli-wip/nix-homebrew";
       inputs.nixpkgs.follows = "nixpkgs";

hosts/adrastea/configuration.nix

@@ -86,8 +86,6 @@
   #   };
   # };
 
-  services.flatpak.enable = true;
-
   boot.initrd.luks.devices."luks-52d1be6d-b32f-41e0-a6d7-2ff52599fe7c".device = "/dev/disk/by-uuid/52d1be6d-b32f-41e0-a6d7-2ff52599fe7c";
 
   services.tlp.enable = true;

hosts/adrastea/default.nix

@@ -17,6 +17,7 @@
       ../../modules/linux/wine
       ../../modules/linux/stylix
       ../../modules/linux/distrobox
+      ../../modules/linux/flatpak
       ../../overlays
       {
         home-manager.useGlobalPkgs = true;

hosts/demeter/configuration.nix

@@ -126,8 +126,6 @@
 
   services.xserver.videoDrivers = [ "nvidia" ];
 
-  services.flatpak.enable = true;
-
   # services.desktopManager.plasma6.enable = true;
 
   # Configure keymap in X11

hosts/demeter/default.nix

@@ -17,6 +17,7 @@
       ../../modules/linux/audio-prod
       ../../modules/linux/stylix
       ../../modules/linux/wine
+      ../../modules/linux/flatpak
       ../../overlays
       {
         home-manager.useGlobalPkgs = true;

modules/linux/flatpak/default.nix

@@ -0,0 +1,45 @@
+# NOTE: this module is IMPURE. Flatpaks are declaratively specified but not
+# versioned. Therefore, they are not included in generational rollbacks and
+# persist between generations. This is not ideal, but at least it is a better
+# situation than imperative installation
+{ inputs, ... }:
+{
+  imports = [
+    inputs.nix-flatpak.nixosModules.nix-flatpak
+  ];
+
+  services.flatpak = {
+    enable = true;
+
+    overrides = {
+      global = {
+        Context.sockets = [
+          "wayland"
+          "!x11"
+          "!fallback-x11"
+        ];
+
+        Environment = {
+          # Fix un-themed cursor in some Wayland apps
+          XCURSOR_PATH = "/run/host/user-share/icons:/run/host/share/icons";
+        };
+      };
+    };
+
+    update.auto = {
+      enable = true;
+      onCalendar = "weekly";
+    };
+
+    packages = [
+      {
+        flatpakref = "https://sober.vinegarhq.org/sober.flatpakref";
+        sha256 = "sha256:1pj8y1xhiwgbnhrr3yr3ybpfis9slrl73i0b1lc9q89vhip6ym2l";
+      }
+      {
+        appId = "org.vinegarhq.Sober";
+        origin = "sober";
+      }
+    ];
+  };
+}