From 777d803b765fa7d13997148c041100aecc464165 Mon Sep 17 00:00:00 2001
From: oddlama <oddlama@oddlama.org>
Date: Mon, 12 Jun 2023 00:17:55 +0200
Subject: [PATCH] feat: add module to allow extending configuration of other
 nodes

---
 modules/distributed-config.nix | 46 ++++++++++++++++++++++++++++++++++
 nix/generate-node.nix          |  2 +-
 2 files changed, 47 insertions(+), 1 deletion(-)
 create mode 100644 modules/distributed-config.nix

diff --git a/modules/distributed-config.nix b/modules/distributed-config.nix
new file mode 100644
index 0000000..647173d
--- /dev/null
+++ b/modules/distributed-config.nix
@@ -0,0 +1,46 @@
+{
+  config,
+  extraLib,
+  lib,
+  nodeName,
+  colmenaNodes,
+  ...
+}: let
+  inherit
+    (lib)
+    attrNames
+    concatMap
+    filter
+    mdDoc
+    mkOption
+    types
+    unique
+    subtractLists
+    ;
+
+  inherit
+    (extraLib)
+    mergeToplevelConfigs
+    ;
+in {
+  options.nodes = mkOption {
+    type = types.attrsOf types.unspecified;
+    default = {};
+    description = mdDoc "Allows extending the configuration of other machines.";
+  };
+
+  config = let
+    otherNodes = filter (n: n != nodeName) (attrNames colmenaNodes);
+    foreignConfigs = map (n: colmenaNodes.${n}.config.nodes.${nodeName} or {}) otherNodes;
+    toplevelAttrs = ["age" "networking" "systemd" "services"];
+  in
+    {
+      assertions =
+        map (n: {
+          assertion = false;
+          message = "Cannot extend configuration using nodes.${n} because the given node is not a registered or not a first-class nixos node (microvm's can't be extended right now).";
+        })
+        (subtractLists (attrNames colmenaNodes) (attrNames config.nodes));
+    }
+    // mergeToplevelConfigs toplevelAttrs foreignConfigs;
+}
diff --git a/nix/generate-node.nix b/nix/generate-node.nix
index cea8d1a..5856345 100644
--- a/nix/generate-node.nix
+++ b/nix/generate-node.nix
@@ -18,7 +18,7 @@ in {
   pkgs = self.pkgs.${nodeMeta.system};
   specialArgs = {
     inherit (nixpkgs) lib;
-    inherit (self) extraLib nodes stateVersion;
+    inherit (self) extraLib nodes stateVersion colmenaNodes;
     inherit inputs nodeName;
     # Only set the nodePath if it is an actual directory
     nodePath =