wip: migrate client modules

modules-clone/nixos/common/nodes.nix

@@ -0,0 +1,69 @@
+# adapted from https://github.com/oddlama/nix-config/blob/main/modules/distributed-config.nix
+{ config, lib, nodes, ... }:
+let
+  nodeName = config.node.name;
+  mkForwardedOption =
+    path:
+    lib.mkOption {
+      type = lib.mkOptionType {
+        name = "Same type that the receiving option `${lib.concatStringsSep "." path}` normally accepts.";
+        merge =
+          _loc: defs:
+          builtins.filter (x: builtins.isAttrs x -> ((x._type or "") != "__distributed_config_empty")) (
+            map (x: x.value) defs
+          );
+      };
+      default = {
+        _type = "__distributed_config_empty";
+      };
+      description = ''
+        Anything specified here will be forwarded to `${lib.concatStringsSep "." path}`
+        on the given node. Forwarding happens as-is to the raw values,
+        so validity can only be checked on the receiving node.
+      '';
+    };
+
+  expandOptions = basePath: optionNames: map (option: basePath ++ [ option ]) optionNames;
+  splitPath = path: lib.splitString "." path;
+
+  forwardedOptions = [
+    (splitPath "boot.kernel.sysctl")
+    (splitPath "networking.nftables.chains.postrouting")
+    (splitPath "services.kanidm.provision.groups")
+    (splitPath "services.kanidm.provision.systems.oauth2")
+    (splitPath "sops.secrets")
+    (splitPath "swarselsystems.server.dns")
+    (splitPath "topology.self.services")
+    (splitPath "environment.persistence")
+  ]
+  ++ expandOptions (splitPath "networking.nftables.firewall") [ "zones" "rules" ]
+  ++ expandOptions (splitPath "services.firezone.gateway") [ "enable" "name" "apiUrl" "tokenFile" "package" "logLevel" ]
+  ++ expandOptions (splitPath "services.nginx") [ "upstreams" "virtualHosts" ]
+  ;
+
+  attrsForEachOption =
+    f: lib.foldl' (acc: path: lib.recursiveUpdate acc (lib.setAttrByPath path (f path))) { } forwardedOptions;
+in
+{
+  options.nodes = lib.mkOption {
+    description = "Options forwarded to the given node.";
+    default = { };
+    type = lib.types.attrsOf (
+      lib.types.submodule {
+        options = attrsForEachOption mkForwardedOption;
+      }
+    );
+  };
+
+  config =
+    let
+      getConfig =
+        path: otherNode:
+        let
+          cfg = nodes.${otherNode}.config.nodes.${nodeName} or null;
+        in
+        lib.optionals (cfg != null) (lib.getAttrFromPath path cfg);
+      mergeConfigFromOthers = path: lib.mkMerge (lib.concatMap (getConfig path) (lib.attrNames nodes));
+    in
+    attrsForEachOption mergeConfigFromOthers;
+}