{ hostname
, target ? null
, extraSources ? { }
}:
let
  sources = import ../nix/sources.nix;
  krops = sources.krops;
  lib = import "${krops}/lib";
  pkgs = import "${krops}/pkgs" { };

  source = lib.evalSource [
    ({
      nixpkgs.git = {
        ref = sources.nixpkgs.rev;
        url = https://github.com/NixOS/nixpkgs;
        shallow = true;
      };
      config.file = toString ../.;
      nixos-config.symlink = "config/machines/${hostname}/configuration.nix";
      secrets.pass = {
        dir = toString ~/.password-store;
        name = "nixos/machines/${hostname}";
      };
    } // extraSources)
  ];
in
pkgs.krops.writeDeploy "deploy-${hostname}" {
  source = source;
  target = lib.mkTarget (if target == null then "root@${hostname}" else target) // {
    extraOptions = [
      # force allocation of tty to allow aborting with ^C and to show build progress
      "-t"
    ];
  };
}