1 files changed, 43 insertions, 0 deletions
diff --git a/krebs/3modules/nixpkgs.nix b/krebs/3modules/nixpkgs.nix
new file mode 100644
index 000000000..4129f9483
--- /dev/null
+++ b/krebs/3modules/nixpkgs.nix
@@ -0,0 +1,43 @@
+{ config, pkgs, lib, ... }:
+with lib;
+let
+  cfg = config.krebs.nixpkgs;
+
+  out = {
+    options.krebs.nixpkgs = api;
+    config = mkIf cfg.enable imp;
+  };
+
+  api = {
+    enable = mkEnableOption "krebs.nixpkgs" // { default = true; };
+
+    allowUnfreePredicate = mkOption {
+      description = ''
+        This option is similar to `nixpkgs.config.allowUnfreePredicate'
+        but can be defined in several modules.  An unfree package will be
+        allowed if any of the defined predicates returns true.
+      '';
+      type = types.nullOr (mkOptionType {
+        name = "Predicate";
+        check = isFunction;
+        merge = _locs: defs: pkg: let
+          evalPredicateDef = def: let
+            allow = def.value pkg;
+          in if cfg.verbose && allow
+            then trace "unfree ‘${pkg.name}’ allowed in ${def.file}" allow
+            else allow;
+        in any evalPredicateDef defs;
+      });
+      default = null;
+    };
+
+    verbose = mkOption {
+      type = types.bool;
+      default = false;
+    };
+  };
+
+  imp = mkIf (cfg.allowUnfreePredicate != null) {
+    nixpkgs.config.allowUnfreePredicate = cfg.allowUnfreePredicate;
+  };
+in out