zigbee2mqtt in nixos

override.nix

{pkgs ? import <nixpkgs> {
    inherit system;
}, system ? builtins.currentSystem}:

let
  nodePackages = import ./default.nix {
    inherit pkgs system;
  };
in
nodePackages // {
  zigbee2mqtt = nodePackages.package.override {
    buildInputs = [ pkgs.nodePackages.node-gyp ];
  };
}

z2m.nix

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

let
  nodePackages = import ./override.nix {
    inherit pkgs; 
  };
in

{
  systemd.services.zigbee2mqtt = {
    wantedBy = ["multi-user.target" ]; 
    after = [ "network.target" ];
    description = "Run zigbee2mqtt as daemon";
    serviceConfig = {
      WorkingDirectory = ''${nodePackages.zigbee2mqtt}/lib/node_modules/zigbee2mqtt'';
      ExecStart = ''${pkgs.nodejs-12_x}/bin/node index.js'';
      StandardOutput = "inherit";
      StandardError = "inherit";
      Restart = "always";
      User = "root";
      StateDirectory = "zigbee  2mqtt";
      #DeviceAllow = "/dev/ttyACM0 rw";
    };
    environment = { ZIGBEE2MQTT_DATA = "/var/lib/zigbee2mqtt"; };
  };
}