Sway

Sway is a tiling Wayland compositor and a drop-in replacement for the i3 window manager for X11. It works with your existing i3 configuration and supports most of i3's features, plus a few extras. i3 migration guide

Installation

Here is a minimal configuration where everything you would expect (like screen sharing and gtk themes) work:

{ config, pkgs, lib, ... }:

let
  # bash script to let dbus know about important env variables and
  # propogate them to relevent services run at the end of sway config
  # see
  # https://github.com/emersion/xdg-desktop-portal-wlr/wiki/"It-doesn't-work"-Troubleshooting-Checklist
  # note: this is pretty much the same as  /etc/sway/config.d/nixos.conf but also restarts  
  # some user services to make sure they have the correct environment variables
  dbus-sway-environment = pkgs.writeTextFile {
    name = "dbus-sway-environment";
    destination = "/bin/dbus-sway-environment";
    executable = true;

    text = ''
  dbus-update-activation-environment --systemd WAYLAND_DISPLAY XDG_CURRENT_DESKTOP=sway
  systemctl --user stop pipewire pipewire-media-session xdg-desktop-portal xdg-desktop-portal-wlr
  systemctl --user start pipewire pipewire-media-session xdg-desktop-portal xdg-desktop-portal-wlr
      '';
  };

  # currently, there is some friction between sway and gtk:
  # https://github.com/swaywm/sway/wiki/GTK-3-settings-on-Wayland
  # the suggested way to set gtk settings is with gsettings
  # for gsettings to work, we need to tell it where the schemas are
  # using the XDG_DATA_DIR environment variable
  # run at the end of sway config
  configure-gtk = pkgs.writeTextFile {
      name = "configure-gtk";
      destination = "/bin/configure-gtk";
      executable = true;
      text = let
        schema = pkgs.gsettings-desktop-schemas;
        datadir = "${schema}/share/gsettings-schemas/${schema.name}";
      in ''
        export XDG_DATA_DIRS=${datadir}:$XDG_DATA_DIRS
        gnome_schema=org.gnome.desktop.interface
        gsettings set $gnome_schema gtk-theme 'Dracula'
        '';
  };


in
{
  environment.systemPackages = with pkgs; [
    alacritty # gpu accelerated terminal
    sway
    dbus-sway-environment
    configure-gtk
    wayland
    glib # gsettings
    dracula-theme # gtk theme
    gnome3.adwaita-icon-theme  # default gnome cursors
    swaylock
    swayidle
    grim # screenshot functionality
    slurp # screenshot functionality
    wl-clipboard # wl-copy and wl-paste for copy/paste from stdin / stdout
    bemenu # wayland clone of dmenu
    mako # notification system developed by swaywm maintainer
  ];


  services.pipewire = {
    enable = true;
    alsa.enable = true;
    pulse.enable = true;
  };


  # xdg-desktop-portal works by exposing a series of D-Bus interfaces
  # known as portals under a well-known name
  # (org.freedesktop.portal.Desktop) and object path
  # (/org/freedesktop/portal/desktop).
  # The portal interfaces include APIs for file access, opening URIs,
  # printing and others.
  services.dbus.enable = true;
  xdg.portal = {
    enable = true;
    wlr.enable = true;
    # gtk portal needed to make gtk apps happy
    extraPortals = [ pkgs.xdg-desktop-portal-gtk ];
    gtkUsePortal = true;
  };

  # enable sway window manager
  programs.sway = {
    enable = true;
    wrapperFeatures.gtk = true;
  };
}

and here are the relevent things you should add to your sway config:

sway config

set $menu bemenu-run

# screenshots
bindsym $mod+c exec grim  -g "$(slurp)" /tmp/$(date +'%H:%M:%S.png')


exec dbus-sway-environment
exec configure-gtk

A few general comments:

• There is some friction between GTK theming and sway. Currently the sway developers suggest using gsettings to set gtk theme attributes as described here [1]. There is currently a plan to allow GTK theme attributes to be set directly in the sway config.
• Running sway as a systemd user service is not recommended [2] [3]
• This wiki page was gutted and rewritten in June 2022. See [4] for the related discussion.

Brightness and volume

If you are on a laptop, you can set up brightness and volume function keys as follows:

/etc/nixos/configuration.nix

users.users.yourusername.extraGroups = [ "video" ];
programs.light.enable = true;

sway config

# Brightness
bindsym XF86MonBrightnessDown exec light -U 10
bindsym XF86MonBrightnessUp exec light -A 10

# Volume
bindsym XF86AudioRaiseVolume exec 'pactl set-sink-volume @DEFAULT_SINK@ +1%'
bindsym XF86AudioLowerVolume exec 'pactl set-sink-volume @DEFAULT_SINK@ -1%'
bindsym XF86AudioMute exec 'pactl set-sink-mute @DEFAULT_SINK@ toggle'

Systemd services

As explained above, we don't run sway itself as a systemd service. There are auxiliary daemons that we do want to run as systemd services, for example Kanshi [5], which implements monitor hot swapping. It would be enabled as follows:

/etc/nixos/configuration.nix

  # kanshi systemd service
  systemd.user.services.kanshi = {
    description = "kanshi daemon";
    serviceConfig = {
      Type = "simple";
      ExecStart = ''${pkgs.kanshi}/bin/kanshi -c kanshi_config_file';
    };
  };

sway config

exec systemctl --user start kanshi.service

When you launch sway, the systemd service is started.