autoupdate: set up a systemd timer

hosts/laptop/configuration.nix

@@ -22,7 +22,8 @@
     ../../hostsModules/laptop/nixos/disk.nix
     ../../modules/nixos/printer.nix
     ../../hostsModules/laptop/nixos/ollama.nix # llm config
-      ../../modules/nixos/mullvad.nix # vpn config
+    ../../modules/nixos/mullvad.nix # vpn config
+    ../../hostsModules/laptop/nixos/autoUpdate.nix # auto update the flakes. Handles notification via libnotify and matrix-commander-rs
   ];
 
 

hosts/laptop/home.nix

@@ -71,8 +71,6 @@
     
     # checks if matrix-commander-rs is installed and logged in
     (pkgs.callPackage ../../hostsModules/laptop/scripts/checkMatrix.nix {})
-    # autoupdate the flake and send notification to system and to matrix
-    (pkgs.callPackage ../../hostsModules/laptop/scripts/autoUpdate.nix {})
 
     (pkgs.callPackage ../../modules/scripts/weather.nix {})
     (pkgs.callPackage ../../modules/scripts/wallpaper.nix {})

hostsModules/laptop/nixos/autoUpdate.nix

@@ -0,0 +1,47 @@
+{ pkgs, ... }:
+
+{
+  # Ensure your script is available system-wide
+  environment.systemPackages = [
+    (pkgs.callPackage ../scripts/autoUpdate.nix {})
+  ];
+  users.users.tomasr = {
+    linger = true;  # lingering is required 
+  };
+
+  systemd.user.services.custom-autoupdate = {
+    description = "NixOS flake auto update";
+
+    serviceConfig = {
+      Type = "oneshot";
+
+      ExecStart = "/run/current-system/sw/bin/custom-autoupdate";
+
+      # safety for long rebuilds
+      TimeoutStartSec = "45min";
+      TimeoutStopSec = "10min";
+
+      # avoid overlap
+      RemainAfterExit = true;
+
+      # tweaks that should make the system run normally during the rebuilds
+      Nice = 10;
+      IOSchedulingClass = "best-effort";
+      IOSchedulingPriority = 7;
+    };
+  };
+
+  # Systemd USER timer
+  systemd.user.timers.custom-autoupdate = {
+    wantedBy = [ "timers.target" ];
+
+    timerConfig = {
+      OnCalendar = "Fri *-*-* 20:00:00"; # runs friday night. If for whatever reason something breaks. I have whole week-end to fix it.
+
+      Persistent = true; # if it happens during shutted down
+
+      # avoids thundering herd on boot
+      RandomizedDelaySec = "2h";
+    };
+  };
+}

modules/nixos/autoUpdate.nix

@@ -0,0 +1,62 @@
+{ pkgs, ... }:
+
+{
+  # Ensure your script is available system-wide
+  environment.systemPackages = [
+    (pkgs.callPackage ./custom-autoupdate.nix {})
+  ];
+
+  # ----------------------------
+  # 🔥 Enable lingering for user services (IMPORTANT)
+  # ----------------------------
+  users.users.tomasr = {
+    isNormalUser = true;
+
+    # other config...
+
+    linger = true;  # <-- declarative equivalent of `loginctl enable-linger`
+  };
+
+  # ----------------------------
+  # ✅ 2. Systemd USER service
+  # ----------------------------
+  systemd.user.services.custom-autoupdate = {
+    description = "NixOS flake auto update";
+
+    serviceConfig = {
+      Type = "oneshot";
+
+      ExecStart = "/run/current-system/sw/bin/custom-autoupdate";
+
+      # safety for long rebuilds
+      TimeoutStartSec = "45min";
+      TimeoutStopSec = "10min";
+
+      # avoid overlap
+      RemainAfterExit = true;
+
+      # 🔥 recommended reliability tweaks
+      Nice = 10;
+      IOSchedulingClass = "best-effort";
+      IOSchedulingPriority = 7;
+    };
+  };
+
+  # ----------------------------
+  # ⏱️ 3. Systemd USER timer
+  # ----------------------------
+  systemd.user.timers.custom-autoupdate = {
+    wantedBy = [ "timers.target" ];
+
+    timerConfig = {
+      OnBootSec = "10min";          # run after boot
+      OnUnitActiveSec = "6h";       # every 6 hours
+
+      # 🔥 ensures missed runs after shutdown happen
+      Persistent = true;
+
+      # avoids thundering herd on boot
+      RandomizedDelaySec = "30min";
+    };
+  };
+}