nixos-config/overlays/private.nix

final: prev:
let
#  val = if prev.withSecrets then
#    assert builtins.pathExists ../private/submodule-is-checked-out; true
#  else
#    false;
val = builtins.pathExists ../private/submodule-is-checked-out;
in {
  withSecrets = builtins.trace
    (if val then "Building _with_ secrets!" else "Building _without_ secrets!")
    val;
  privatePath = name:
    let path = "/etc/nixos/private/${name}";
    in if final.withSecrets then
      assert builtins.pathExists path; path
    else
      path;
  privateValue = default: name:
    if final.withSecrets then import (../private + "/${name}.nix") else default;
  privateFile = name:
    if final.withSecrets then
      ../private + "/${name}"
    else
      builtins.toFile "missing-secret-file-${name}" "";
}