reproduce issue of missing default value for wheel attribute, fixed by uncommenting environment resource type

rm deployment

rm imports

deployment/data-model-test.nix

@@ -1,7 +1,7 @@
 let
   inherit (import ../default.nix { }) pkgs inputs;
   inherit (pkgs) lib;
-  inherit (lib) mkOption;
+  inherit (lib) mkOption types;
   eval =
     module:
     (lib.evalModules {
@@ -23,34 +23,144 @@ in
         fediversity = eval (
           { config, ... }:
           {
+            _class = "fediversity-settings";
             config = {
+              resources.nixos-configuration = {
+                description = "An entire NixOS configuration";
+                request =
+                  { ... }:
+                  {
+                    _class = "fediversity-resource-request";
+                    options.config = mkOption {
+                      description = "Any options from NixOS";
+                    };
+                  };
+
+                policy =
+                  { ... }:
+                  {
+                    _class = "fediversity-resource-policy";
+
+                    options = {
+                      extra-config = mkOption {
+                        description = "Any options from NixOS";
+                      };
+                      apply = mkOption {
+                        type = with types; functionTo raw;
+                        default = policy: requests: lib.mkMerge (requests ++ [ policy.extra-config ]);
+                      };
+                    };
+                  };
+              };
+              resources.login-shell = {
+                _class = "fediversity-resource";
+                description = "The operator needs to be able to log into the shell";
+                request =
+                  { ... }:
+                  {
+                    _class = "fediversity-resource-request";
+                    options = {
+                      wheel = mkOption {
+                        description = "Whether the login user needs root permissions";
+                        type = types.bool;
+                        default = false;
+                      };
+                      packages = mkOption {
+                        description = "Packages that need to be available in the user environment";
+                        type = with types; attrsOf package;
+                      };
+                    };
+                  };
+                policy =
+                  { ... }:
+                  {
+                    _class = "fediversity-resource-policy";
+                    options = {
+                      username = mkOption {
+                        description = "Username for the operator";
+                        type = types.str; # TODO: use the proper constraints from NixOS
+                      };
+                      wheel = mkOption {
+                        description = "Whether to allow login with root permissions";
+                        type = types.bool;
+                        default = false;
+                      };
+                      apply = mkOption {
+                        type = with types; functionTo raw; # TODO: splice out the user type from NixOS
+                        default =
+                          policy: requests:
+                          let
+                            # Filter out requests that need wheel if policy doesn't allow it
+                            validRequests = lib.filterAttrs (_name: req: !req.wheel || policy.wheel) requests;
+                          in
+                          lib.optionalAttrs (validRequests != { }) {
+                            ${policy.username} = {
+                              isNormalUser = true;
+                              packages = with lib; concatMap (request: attrValues request.packages) (attrValues validRequests);
+                              extraGroups = lib.optional policy.wheel "wheel";
+                            };
+                          };
+                      };
+                    };
+                  };
+              };
               applications.hello =
                 { ... }:
                 {
+                  _class = "fediversity-application";
                   description = ''Command-line tool that will print "Hello, world!" on the terminal'';
                   module =
                     { ... }:
                     {
+                      _class = "fediversity-application-config";
                       options = {
                         enable = lib.mkEnableOption "Hello in the shell";
                       };
                     };
-                  implementation =
+                  resources =
                     cfg:
                     lib.optionalAttrs cfg.enable {
-                      dummy.login-shell.packages.hello = pkgs.hello;
+                      dummy.login-shell.packages = {
+                        # hello = pkgs.hello;
+                      };
                     };
                 };
+              environments.single-nixos-vm = environment: {
+                _class = "fediversity-environment";
+                resources.shell.login-shell = {
+                  username = "operator";
+                  # wheel = false; # FIXME: why do i need to make this explicit, if a default was supposed to be set?
+                };
+                implementation = requests: {
+                  _class = "nixos";
+                  users.users = (
+                    config.resources.login-shell.policy.apply environment.config.resources.shell.login-shell (
+                      lib.concatMapAttrs (
+                        _application: resources:
+                        lib.mapAttrs (_k: lib.getAttr "login-shell") (
+                          lib.filterAttrs (_name: value: value ? login-shell) resources
+                        )
+                      ) requests
+                    )
+                  );
+                };
+              };
             };
             options = {
               example-configuration = mkOption {
                 type = config.configuration;
                 readOnly = true;
                 default = {
+                  _class = "fediversity-configuration";
                   enable = true;
                   applications.hello.enable = true;
                 };
               };
+              example-deployment = mkOption {
+                type = types.raw;
+                readOnly = true;
+                default = config.environments.single-nixos-vm.deployment config.example-configuration;
+              };
             };
           }
         );
@@ -58,13 +168,16 @@ in
       {
         inherit (fediversity)
           example-configuration
+          example-deployment
           ;
+        num-packages = lib.lists.length fediversity.example-deployment.users.users.operator.packages;
       };
     expected = {
       example-configuration = {
         enable = true;
         applications.hello.enable = true;
       };
+      num-packages = 1;
     };
   };
 }

deployment/data-model.nix

@@ -9,81 +9,184 @@ let
     attrsOf
     attrTag
     deferredModuleWith
-    submodule
+    submoduleWith
     optionType
     functionTo
+    raw
     ;
 
   functionType = import ./function.nix;
-  application-resources = {
+
-    options.resources = mkOption {
+  configuration = mkOption {
-      # TODO: maybe transpose, and group the resources by type instead
+    description = "Configuration type declaring options to be set by operators";
-      type = attrsOf (
+    type = optionType;
-        attrTag (lib.mapAttrs (_name: resource: mkOption { type = resource.request; }) config.resources)
+    readOnly = true;
-      );
+    default = submoduleWith {
+      class = "fediversity-configuration";
+      modules = [
+        {
+          options = {
+            enable = lib.mkEnableOption {
+              description = "your Fediversity configuration";
+            };
+            applications = lib.mapAttrs (
+              _name: application:
+              mkOption {
+                description = application.description;
+                type = submoduleWith {
+                  class = "fediversity-application-config";
+                  modules = [ application.module ];
+                };
+                default = { };
+              }
+            ) config.applications;
+          };
+        }
+      ];
     };
   };
 in
 {
-  _class = "nixops4Deployment";
+  _class = "fediversity-settings";
-
   options = {
+    inherit configuration;
+    resources = mkOption {
+      description = "Collection of deployment resources that can be required by applications and policed by hosting providers";
+      type = attrsOf (submoduleWith {
+        class = "fediversity-resource";
+        modules = [
+          (
+            { ... }:
+            {
+              options = {
+                description = mkOption {
+                  description = "Description of the resource to help application module authors and hosting providers to work with it";
+                  type = types.str;
+                };
+                request = mkOption {
+                  description = "Options for declaring resource requirements by an application, a description of how the resource is consumed or accessed";
+                  type = deferredModuleWith { staticModules = [ { _class = "fediversity-resource-request"; } ]; };
+                };
+                policy = mkOption {
+                  description = "Options for configuring the resource policy for the hosting provider, a description of how the resource is made available";
+                  type = submoduleWith {
+                    class = "fediversity-resource-policy";
+                    modules = [
+                      {
+                        options.apply = mkOption {
+                          description = "Apply the policy to a request";
+                        };
+                      }
+                    ];
+                  };
+                };
+              };
+            }
+          )
+        ];
+      });
+    };
     applications = mkOption {
       description = "Collection of Fediversity applications";
-      type = attrsOf (
+      type = attrsOf (submoduleWith {
-        submodule (application: {
+        class = "fediversity-application";
-          _class = "fediversity-application";
+        modules = [
-          options = {
+          {
-            description = mkOption {
+            options = {
-              description = "Description to be shown in the application overview";
+              description = mkOption {
-              type = types.str;
+                description = "Description to be shown in the application overview";
-            };
+                type = types.str;
-            module = mkOption {
+              };
-              description = "Operator-facing configuration options for the application";
+              module = mkOption {
-              type = deferredModuleWith { staticModules = [ { _class = "fediversity-application-config"; } ]; };
+                description = "Operator-facing configuration options for the application";
-            };
+                type = deferredModuleWith { staticModules = [ { _class = "fediversity-application-config"; } ]; };
-            implementation = mkOption {
+              };
-              description = "Mapping of application configuration to deployment resources, a description of what an application needs to run";
+              resources = mkOption {
-              type = application.config.config-mapping.function-type;
+                description = "Mapping of application configuration to deployment resources, a description of what an application needs to run";
-            };
+                # TODO: maybe transpose, and group the resources by type instead
-            resources = mkOption {
+                type = functionTo (
-              description = "Compute resources required by an application";
+                  attrsOf (
-              type = functionTo application.config.config-mapping.output-type;
+                    attrTag (
-              readOnly = true;
+                      lib.mapAttrs (
-              default = input: (application.config.implementation input).output;
+                        _name: resource: mkOption { type = types.submodule resource.request; }
-            };
+                      ) config.resources
-            config-mapping = mkOption {
+                    )
-              description = "Function type for the mapping from application configuration to required resources";
+                  )
-              type = submodule functionType;
+                );
-              readOnly = true;
-              default = {
-                input-type = application.config.module;
-                output-type = application-resources;
               };
             };
-          };
+          }
-        })
+        ];
-      );
+      });
     };
-    configuration = mkOption {
+    environments = mkOption {
-      description = "Configuration type declaring options to be set by operators";
+      description = "Run-time environments for Fediversity applications to be deployed to";
-      type = optionType;
+      type = attrsOf (submoduleWith {
-      readOnly = true;
+        class = "fediversity-environment";
-      default = submodule {
+        modules = [
-        options = {
+          (environment: {
-          enable = lib.mkEnableOption {
+            options = {
-            description = "your Fediversity configuration";
+              resources = mkOption {
-          };
+                description = ''
-          applications = lib.mapAttrs (
+                  Resources made available by the hosting provider, and their policies.
-            _name: application:
+
-            mkOption {
+                  Setting this is optional, but provides a place to declare that information for programmatic use in the resource mapping.
-              description = application.description;
+                '';
-              type = submodule application.module;
+                # TODO: maybe transpose, and group the resources by type instead
-              default = { };
+                # # FIXME: error: The option `environments.single-nixos-vm.resources.shell.login-shell.apply' does not exist. Definition values:
-            }
+                # # - In `<unknown-file>': <function>
-          ) config.applications;
+                # # However there are no options defined in `environments.single-nixos-vm.resources.shell.login-shell'. Are you sure you've
-        };
+                # # declared your options properly? This can happen if you e.g. declared your options in `types.submodule'
-      };
+                # # under `config' rather than `options'.
+                # type = attrsOf (
+                #   attrTag (
+                #     lib.mapAttrs (
+                #       _name: resource:
+                #       mkOption {
+                #         type = submoduleWith {
+                #           class = "fediversity-resource-policy";
+                #           modules = [ resource.policy ];
+                #         };
+                #       }
+                #     ) config.resources
+                #   )
+                # );
+              };
+              implementation = mkOption {
+                description = "Mapping of resources required by applications to available resources; the result can be deployed";
+                type = functionTo raw;
+              };
+              resource-mapping = mkOption {
+                description = "Function type for the mapping from resources to a (NixOps4) deployment";
+                type = submoduleWith {
+                  class = "module-function";
+                  modules = [ functionType ];
+                };
+                readOnly = true;
+                default = {
+                  input-type = configuration;
+                  output-type = raw;
+                };
+              };
+              deployment = mkOption {
+                description = "Generate a deployment from a configuration";
+                type = functionTo raw;
+                readOnly = true;
+                default =
+                  cfg:
+                  # TODO: check cfg.enable.true
+                  let
+                    required-resources = lib.mapAttrs (
+                      name: application-settings: config.applications.${name}.resources application-settings
+                    ) cfg.applications;
+                  in
+                  (environment.config.implementation required-resources);
+
+              };
+            };
+          })
+        ];
+      });
     };
   };
 }