feat(submodules): add support for submodule exports

modules/submodule.nix

@@ -29,10 +29,16 @@ with lib;
       default = [];
     };
 
+    exports = mkOption {
+      description = "Attribute set of functions to export";
+      type = types.attrs;
+      default = {};
+    };
+
     passthru = mkOption {
       description = "Attribute set to passthru";
-      default = {};
       type = types.attrs;
+      default = {};
     };
 
     args._empty = mkOption {};

modules/submodules.nix

@@ -144,11 +144,17 @@ in {
                 description = "Submodule definition";
                 type = types.attrs;
               };
+
+              exportAs = mkOption {
+                description = "Name under which to register exports";
+                type = types.nullOr types.str;
+                default = null;
+              };
             };
 
             config = {
               definition = {
-                inherit (evaledSubmodule.config.submodule) name description version tags;
+                inherit (evaledSubmodule.config.submodule) name description version tags exports;
               };
 
               features = evaledSubmodule.config._module.features;
@@ -230,6 +236,11 @@ in {
 
   config = mkMerge ([
     {
+      # register exported functions as args
+      _module.args = mkMerge (map (submodule: {
+        ${submodule.exportAs} = submodule.definition.exports;
+      }) (filter (submodule: submodule.exportAs != null) cfg.imports));
+
       _module.features = ["submodules"];
 
       submodules.specialArgs.kubenix = kubenix;

tests/default.nix

@@ -36,6 +36,7 @@ let
           ./submodules/simple.nix
           ./submodules/defaults.nix
           ./submodules/versioning.nix
+          ./submodules/exports.nix
         ];
         testing.args = {
           inherit images k8sVersion;

tests/submodules/exports.nix

@@ -0,0 +1,32 @@
+{ name, config, lib, kubenix, subm-lib, ... }:
+
+with lib;
+
+let
+  submodule = {
+    imports = [ kubenix.modules.submodule ];
+
+    config.submodule = {
+      name = "subm";
+      exports = {
+        inherit id;
+      };
+    };
+  };
+in {
+  imports = with kubenix.modules; [ test submodules ];
+
+  test = {
+    name = "submodules-exports";
+    description = "Submodules exports test";
+    assertions = [{
+      message = "should have library exported";
+      assertion = subm-lib.id 1 == 1;
+    }];
+  };
+
+  submodules.imports = [{
+    modules = [submodule];
+    exportAs = "subm-lib";
+  }];
+}