From b609ff4fcf48b2124d94bf1052c303a36c8cabf1 Mon Sep 17 00:00:00 2001
From: Mathijs Kwik <mathijs@bluescreen303.nl>
Date: Sat, 21 Jul 2012 17:35:50 +0200
Subject: [PATCH] allow out-of-tree nixos modules

The environment variable "NIXOS_EXTRA_MODULES" is now checked to
contain a path to a file similar to modules/module-list.nix.

This gives the ability to include nixos modules that are not in the
nixos source tree.

This can be useful for modules that are still experimental, or which
aren't useful for other nixos users. Of course, this was already
possible to do this using a forked nixos tree, but with this
functionality, you can just rely on the nixos channel, easing things a
lot.
---
 default.nix               | 9 ++++++---
 modules/security/sudo.nix | 1 +
 2 files changed, 7 insertions(+), 3 deletions(-)

diff --git a/default.nix b/default.nix
index fda19c3a149..ca69f07ef31 100644
--- a/default.nix
+++ b/default.nix
@@ -1,12 +1,15 @@
 { configuration ? import ./lib/from-env.nix "NIXOS_CONFIG" <nixos-config>
+, extraModulesPath ? builtins.getEnv "NIXOS_EXTRA_MODULES" 
 , system ? builtins.currentSystem
 }:
 
 let
 
+  extraModules = if extraModulesPath == "" then [] else import extraModulesPath;
+
   eval = import ./lib/eval-config.nix {
     inherit system;
-    modules = [ configuration ];
+    modules = [ configuration ] ++ extraModules;
   };
 
   inherit (eval) config pkgs;
@@ -14,7 +17,7 @@ let
   # This is for `nixos-rebuild build-vm'.
   vmConfig = (import ./lib/eval-config.nix {
     inherit system;
-    modules = [ configuration ./modules/virtualisation/qemu-vm.nix ];
+    modules = [ configuration ./modules/virtualisation/qemu-vm.nix ] ++ extraModules;
   }).config;
 
   # This is for `nixos-rebuild build-vm-with-bootloader'.
@@ -24,7 +27,7 @@ let
       [ configuration
         ./modules/virtualisation/qemu-vm.nix
         { virtualisation.useBootLoader = true; }
-      ];
+      ] ++ extraModules;
   }).config;
 
 in
diff --git a/modules/security/sudo.nix b/modules/security/sudo.nix
index 76c325d8d8f..aac592619c5 100644
--- a/modules/security/sudo.nix
+++ b/modules/security/sudo.nix
@@ -35,6 +35,7 @@ in
           # Environment variables to keep for root and %wheel.
           Defaults:root,%wheel env_keep+=LOCALE_ARCHIVE
           Defaults:root,%wheel env_keep+=NIX_PATH
+          Defaults:root,%wheel env_keep+=NIXOS_EXTRA_MODULES
           Defaults:root,%wheel env_keep+=TERMINFO_DIRS
 
           # Keep SSH_AUTH_SOCK so that pam_ssh_agent_auth.so can do its magic.