nixdots/system/roles/workstation/services/earlyoom.nix

{pkgs, lib, config, ...}: let
  inherit (lib) mkIf;
  deviceType = config.myOptions.device.roles.type;
  acceptedTypes = ["laptop" "desktop"];
in {
  config = mkIf (builtins.elem deviceType acceptedTypes) {
    # https://dataswamp.org/~solene/2022-09-28-earlyoom.html
    # avoid the linux kernel locking itself when we're putting too much strain on the memory
    # this helps avoid having to shut down forcefully when we OOM
    services.earlyoom = {
      enable = true;
      enableNotifications = true; # annoying, but we want to know what's killed
      freeSwapThreshold = 2;
      freeMemThreshold = 2;
      extraArgs = [
        "-g" # kill all processes within a process group
        "--avoid 'Hyprland|soffice|soffice.bin|firefox|thunderbird)$'" # things we want to not kill
        "--prefer '^(electron|.*.exe)$'" # I wish we could kill electron permanently
      ];

      # we should ideally write the logs into a designated log file; or even better, to the journal
      # for now we can hope this echo sends the log to somewhere we can observe later
      killHook = pkgs.writeShellScript "earlyoom-kill-hook" ''
        echo "Process $EARLYOOM_NAME ($EARLYOOM_PID) was killed"
      '';
    };
  };
}