data model: add run-time configuration

deployment/data-model-test.nix

@@ -11,17 +11,18 @@ let
     }).config;
 in
 {
+  _class = "nix-unit";
+
   test-eval = {
     expr =
       let
         example = eval {
-          runtime-environments.bar.nixos = {
+          runtime-configurations.nixos =
-            module =
             { ... }:
             {
               system.stateVersion = "25.05";
             };
-          };
+          runtime-environments.bar.nixos = { };
           applications.foo = {
             module =
               { pkgs, ... }:
@@ -34,11 +35,13 @@ in
         };
       in
       {
-        has-runtime = lib.isAttrs example.runtime-environments.bar.nixos.module;
+        has-runtime-configuration = lib.isAttrs example.runtime-configurations.nixos;
+        has-runtime-environment = lib.isAttrs example.runtime-environments.bar.nixos.module;
         has-application = lib.isAttrs example.applications.foo.module;
       };
     expected = {
-      has-runtime = true;
+      has-runtime-configuration = true;
+      has-runtime-environment = true;
       has-application = true;
     };
   };

deployment/data-model.nix

@@ -1,32 +1,43 @@
 {
   lib,
+  config,
   ...
 }:
 let
-  inherit (lib) types mkOption;
+  inherit (lib) attrNames mkOption genAttrs;
-in
+  inherit (lib.types)
-with types;
+    attrsOf
-{
+    attrTag
-  options = {
+    deferredModule
-    runtime-environments = mkOption {
+    submoduleWith
-      description = "Collection of runtime environments into which applications can be deployed";
+    ;
-      type = attrsOf (attrTag {
+  runtime-configuration = mkOption {
+    description = "The NixOS module of a run-time environment";
+    type = deferredModule;
+    default = {
+      _class = "nixos";
+    };
+  };
+  runtime-environment = attrTag {
     nixos = mkOption {
-          description = "A single NixOS machine";
+      type = submoduleWith {
-          type = submodule {
+        modules = [
+          {
             options = {
               module = mkOption {
-                description = "The NixOS module describing the base configuration for that machine";
+                description = "The NixOS module of the run-time environment";
                 type = deferredModule;
+                default = config.runtime-configurations.nixos;
+                readOnly = true;
+              };
+            };
+          }
+        ];
       };
     };
   };
-        };
+  application = submoduleWith {
-      });
+    description = "A Fediversity application";
-    };
-    applications = mkOption {
-      description = "Collection of Fediversity applications";
-      type = attrsOf (submoduleWith {
     modules = [
       {
         options = {
@@ -37,7 +48,21 @@ with types;
         };
       }
     ];
-      });
+  };
+in
+{
+  options = {
+    runtime-configurations = mkOption {
+      description = "Collection of runtime environments into which applications can be deployed";
+      type = attrTag (genAttrs (attrNames runtime-environment.nestedTypes) (_: runtime-configuration));
+    };
+    runtime-environments = mkOption {
+      description = "Collection of runtime environments into which applications can be deployed";
+      type = attrsOf runtime-environment;
+    };
+    applications = mkOption {
+      description = "Collection of Fediversity applications";
+      type = attrsOf application;
     };
   };
 }