{ pkgs ? import ../nixpkgs.nix {} }:
let
  lib = pkgs.lib;
  gridlib = import ./lib;
  inherit (gridlib.pkgs) ourpkgs;
  grids-path = "${builtins.toString ./.}/grid";
  grid-configs = lib.mapAttrs (n: v: grids-path + "/${n}/grid.nix") (lib.filterAttrs (n: v: v == "directory") (builtins.readDir grids-path));
  # It would be useful if morph exposed this as a function.
  # https://github.com/DBCDK/morph/pull/166
  morph-eval = networkExpr: (import "${pkgs.morph.lib}/eval-machines.nix") { inherit networkExpr; };
  grids = lib.mapAttrs (n: v: (morph-eval v)) grid-configs;
  # Derivation with symlinks to the morph output for each grid.
  output = pkgs.runCommand "privatestorage-morph"
    { preferLocalBuild = true; allowSubstitutes = false; passthru = { inherit gridlib ourpkgs grids; }; }
    ''
      mkdir $out
      ${lib.concatStringsSep "\n" (
      lib.mapAttrsToList (
        name: morph:
          let
            output = morph.machines {
              # It would be nice if we didn't need to write this data to a file.
              # https://github.com/DBCDK/morph/pull/186
              argsFile = pkgs.writeText "args" (builtins.toJSON { Names = lib.attrNames morph.nodes; });
            };
          in
            ''
              ln -s ${output} $out/${lib.escapeShellArg name}
            ''
      ) grids
    )}'';
in output