allow different deployment types (#498)

Reviewed-on: #498

deployment/data-model-test.nix

@@ -13,7 +13,6 @@ let
         ./data-model.nix
       ];
     }).config;
-  nixops4Deployment = inputs.nixops4.modules.nixops4Deployment.default;
   inherit (inputs.nixops4.lib) mkDeployment;
 in
 {
@@ -32,7 +31,7 @@ in
     expr =
       let
         fediversity = eval (
-          { config, ... }:
+          { config, options, ... }:
           {
             config = {
               resources.login-shell = {
@@ -112,7 +111,7 @@ in
                   resources.operator-environment.login-shell.username = "operator";
                   implementation = requests: {
                     input = requests;
-                    output =
+                    output.nixops4 =
                       { providers, ... }:
                       {
                         providers = {
@@ -145,7 +144,7 @@ in
                 };
               };
               example-deployment = mkOption {
-                type = types.submodule nixops4Deployment;
+                type = options.deployments.nestedType;
                 readOnly = true;
                 default = config.environments.single-nixos-vm.deployment config.example-configuration;
               };

deployment/data-model.nix

@@ -39,6 +39,12 @@ let
       }
     ];
   };
+  deployment = attrTag {
+    nixops4 = mkOption {
+      description = "A NixOps4 NixOS deployment. For an example, see https://github.com/nixops4/nixops4-nixos/blob/main/example/deployment.nix.";
+      type = nixops4Deployment;
+    };
+  };
 in
 {
   options = {
@@ -145,12 +151,12 @@ in
               type = environment.config.resource-mapping.function-type;
             };
             resource-mapping = mkOption {
-              description = "Function type for the mapping from resources to a (NixOps4) deployment";
+              description = "Function type for the mapping from resources to a deployment";
               type = submodule functionType;
               readOnly = true;
               default = {
                 input-type = application-resources;
-                output-type = nixops4Deployment;
+                output-type = deployment;
               };
             };
             # TODO(@fricklerhandwerk): maybe this should be a separate thing such as `fediversity-setup`,