Manage waybar start with systemd

users/simon/modules/sway.nix

@@ -32,6 +32,8 @@ let
 
   cfg = config.wayland.windowManager.sway.config;
   thinsp = " ";
+
+  waybar = (pkgs.waybar.override { pulseSupport = true; }); # FIXME: Remove override with 21.03 (https://github.com/NixOS/nixpkgs/pull/98490)
 in
 lib.mkIf config.sbruder.gui.enable {
   wayland.windowManager.sway = {
@@ -166,9 +168,7 @@ lib.mkIf config.sbruder.gui.enable {
         "--locked ${cfg.modifier}+q" = ''exec 'test $(swaymsg -t get_outputs | ${pkgs.jq}/bin/jq "[.[].dpms] | any") = "true" && swaymsg "output * dpms off" || swaymsg "output * dpms on"'';
       };
 
-      bars = [
-        { command = "waybar"; }
-      ];
+      bars = [ ]; # started by systemd service
 
       assigns = {
         "2" = [
@@ -251,14 +251,36 @@ lib.mkIf config.sbruder.gui.enable {
     fi
   '';
 
-  home.packages = with pkgs; [
+  home.packages = (with pkgs; [
     alacritty # terminal
     brightnessctl # control screen brightness
     sway-contrib.grimshot # screenshots
-    (waybar.override { pulseSupport = true; }) # better status bar FIXME: Remove override with 21.03 (https://github.com/NixOS/nixpkgs/pull/98490)
     wdisplays # graphical output manager
+  ]) ++ [
+    waybar # better status bar FIXME: see above
   ];
 
+  # taken from <home-manager/modules/programs/waybar.nix>
+  systemd.user.services.waybar = {
+    Unit = {
+      Description = "Highly customizable Wayland bar for Sway and Wlroots based compositors.";
+      Documentation = "https://github.com/Alexays/Waybar/wiki";
+      PartOf = [ "graphical-session.target" ];
+    };
+
+    Service = {
+      Type = "dbus";
+      BusName = "fr.arouillard.waybar";
+      ExecStart = "${waybar}/bin/waybar"; # FIXME see above
+      Restart = "always";
+      RestartSec = "1sec";
+    };
+
+    Install = {
+      WantedBy = [ "graphical-session.target" ];
+    };
+  };
+
   xdg.configFile = {
     # home-manager’s waybar module performs additional checks that are overly strict
     "waybar/config".text = builtins.toJSON {