Commit f34917b1 authored by Lin Jian's avatar Lin Jian Committed by pennae
Browse files

nixos/kanata: do not use path activation 

Since 1.2.0, kanata handles missing keyboards well:
- only one keyboard need to be present when kanata starts;
- if linux-continue-if-no-devs-found is set to yes, all keyboards can
be missing at the beginning;
- all keyboards can be (un)pluged when kanata is running.

For simplicity, linux-continue-if-no-devs-found is set to yes and
systemd patch activation is removed.
parent efd1d7ed

nixos/modules/services/hardware/kanata.nix

+11 −56
Original line number Diff line number Diff line
@@ -11,16 +11,7 @@ let 
        type = types.addCheck (types.listOf types.str)

          (devices: (length devices) > 0);

        example = [ "/dev/input/by-id/usb-0000_0000-event-kbd" ];

        # TODO replace note with tip, which has not been implemented yet in

        # nixos/lib/make-options-doc/mergeJSON.py

        description = mdDoc ''

          Paths to keyboard devices.



          ::: {.note}

          To avoid unnecessary triggers of the service unit, unplug devices in

          the order of the list.

          :::

        '';

        description = mdDoc "Paths to keyboard devices.";

      };

      config = mkOption {

        type = types.lines;
@@ -53,8 +44,12 @@ let 
        default = "";

        example = "danger-enable-cmd yes";

        description = mdDoc ''

          Configuration of `defcfg` other than `linux-dev`. See [example

          config files](https://github.com/jtroo/kanata) for more information.

          Configuration of `defcfg` other than `linux-dev` (generated

          from the devices option) and

          `linux-continue-if-no-devs-found` (hardcoded to be yes).



          See [example config files](https://github.com/jtroo/kanata)

          for more information.

        '';

      };

      extraArgs = mkOption {
@@ -81,20 +76,14 @@ let 
  mkConfig = name: keyboard: pkgs.writeText "${mkName name}-config.kdb" ''

    (defcfg

      ${keyboard.extraDefCfg}

      linux-dev ${mkDevices keyboard.devices})

      linux-dev ${mkDevices keyboard.devices}

      linux-continue-if-no-devs-found yes)



    ${keyboard.config}

  '';



  mkService = name: keyboard: nameValuePair (mkName name) {

    description = "kanata for ${mkDevices keyboard.devices}";



    # Because path units are used to activate service units, which

    # will start the old stopped services during "nixos-rebuild

    # switch", stopIfChanged here is a workaround to make sure new

    # services are running after "nixos-rebuild switch".

    stopIfChanged = false;



    wantedBy = [ "multi-user.target" ];

    serviceConfig = {

      ExecStart = ''

        ${cfg.package}/bin/kanata \
@@ -146,33 +135,6 @@ let 
      UMask = "0077";

    };

  };



  mkPathName = i: name: "${mkName name}-${toString i}";



  mkPath = name: n: i: device:

    nameValuePair (mkPathName i name) {

      description =

        "${toString (i+1)}/${toString n} kanata trigger for ${name}, watching ${device}";

      wantedBy = optional (i == 0) "multi-user.target";

      pathConfig = {

        PathExists = device;

        # (ab)use systemd.path to construct a trigger chain so that the

        # service unit is only started when all paths exist

        # however, manual of systemd.path says Unit's suffix is not ".path"

        Unit =

          if (i + 1) == n

          then "${mkName name}.service"

          else "${mkPathName (i + 1) name}.path";

      };

      unitConfig.StopPropagatedFrom = optional (i > 0) "${mkName name}.service";

    };



  mkPaths = name: keyboard:

    let

      n = length keyboard.devices;

    in

    imap0 (mkPath name n) keyboard.devices

  ;

in

{

  options.services.kanata = {
@@ -201,14 +163,7 @@ in 
  config = mkIf cfg.enable {

    hardware.uinput.enable = true;



    systemd = {

      paths = trivial.pipe cfg.keyboards [

        (mapAttrsToList mkPaths)

        concatLists

        listToAttrs

      ];

      services = mapAttrs' mkService cfg.keyboards;

    };

    systemd.services = mapAttrs' mkService cfg.keyboards;

  };



  meta.maintainers = with maintainers; [ linj ];