buildClan function: export all machines via nixosModules/darwinModules

We want each machine not only to be exposed via nixosConfigurations but also as a module.
This allows re-importing the machine in tests and override the architecture for example.

docs/site/guides/getting-started/secrets.md

@@ -100,7 +100,7 @@ are loaded when using Clan:
       };
     in
     {
-      inherit (clan) nixosConfigurations clanInternals;
+      inherit (clan) nixosConfigurations nixosModules clanInternals;
 
       # elided for brevity
     };

lib/build-clan/interface.nix

@@ -162,6 +162,32 @@ in
       default = { };
     };
 
+    nixosModules = lib.mkOption {
+      # Hide from documentation.
+      # Exposed at the top-level of the flake, clan.nixosModules should not used by the user.
+      # Instead, the user should use the `.#nixosModules` attribute of the flake output.
+      visible = false;
+      type = types.lazyAttrsOf types.raw;
+      default = { };
+      description = ''
+        NixOS modules that are generated by clan.
+        These are used to generate the `nixosConfigurations`.
+      '';
+    };
+
+    darwinModules = lib.mkOption {
+      # Hide from documentation.
+      # Exposed at the top-level of the flake, clan.darwinModules should not used by the user.
+      # Instead, the user should use the `.#darwinModules` attribute of the flake output.
+      visible = false;
+      type = types.lazyAttrsOf types.raw;
+      default = { };
+      description = ''
+        Darwin modules that are generated by clan.
+        These are used to generate the `darwinConfigurations`.
+      '';
+    };
+
     # flake.clanInternals
     clanInternals = lib.mkOption {
       # Hide from documentation. Exposes internals to the cli.

lib/build-clan/machineModules/forName.nix

@@ -26,7 +26,4 @@
       inherit name;
     };
   };
-
-  # TODO: move into nixosModules
-  networking.hostName = lib.mkDefault name;
 }

lib/build-clan/module.nix

@@ -7,11 +7,16 @@
   ...
 }:
 let
+  inherit (lib)
+    flip
+    mapAttrs'
+    ;
+
   inherit (config)
     directory
+    inventory
     pkgsForSystem
     specialArgs
-    inventory
     ;
 
   inherit (clan-core.clanLib.inventory) buildInventory;
@@ -75,6 +80,31 @@ let
     }
   ) allMachines;
 
+  # Expose reusable modules these can be imported or wrapped or instantiated
+  # - by the user
+  # - by some test frameworks
+  # IMPORTANT!: It is utterly important that we don't add any logic outside of these modules, as it would get tested.
+  nixosModules' = lib.filterAttrs (
+    name: _: inventory.machines.${name}.machineClass or "nixos" == "nixos"
+  ) (config.outputs.moduleForMachine);
+  darwinModules' = lib.filterAttrs (
+    name: _: inventory.machines.${name}.machineClass or "nixos" == "darwin"
+  ) (config.outputs.moduleForMachine);
+
+  nixosModules = flip mapAttrs' nixosModules' (
+    name: machineModule: {
+      name = "clan-machine-${name}";
+      value = machineModule;
+    }
+  );
+
+  darwinModules = flip mapAttrs' darwinModules' (
+    name: machineModule: {
+      name = "clan-machine-${name}";
+      value = machineModule;
+    }
+  );
+
   nixosConfigurations = lib.filterAttrs (name: _: machineClasses.${name} == "nixos") configurations;
   darwinConfigurations = lib.filterAttrs (name: _: machineClasses.${name} == "darwin") configurations;
 
@@ -180,6 +210,9 @@ in
               # - darwinModules (_class = darwin)
               (lib.optionalAttrs (clan-core ? "${_class}Modules") clan-core."${_class}Modules".clanCore)
             ] ++ lib.optionals (_class == "nixos") (v.machineImports or [ ]);
+
+            # default hostname
+            networking.hostName = lib.mkDefault name;
           }
         )
       ) inventoryClass.machines)
@@ -193,6 +226,10 @@ in
       self = lib.mkDefault config.self;
     };
 
+    # expose all machines as modules for re-use
+    inherit nixosModules;
+    inherit darwinModules;
+
     # Ready to use configurations
     # These are only shallow wrapping the 'nixosModules' or 'darwinModules' with
     # lib.nixosSystem
@@ -200,17 +237,6 @@ in
     inherit darwinConfigurations;
 
     clanInternals = {
-      # Expose reusable modules these can be imported or wrapped or instantiated
-      # - by the user
-      # - by some test frameworks
-      # IMPORTANT!: It is utterly important that we don't add any logic outside of these modules, as it would get tested.
-      nixosModules = lib.filterAttrs (
-        name: _: inventory.machines.${name}.machineClass or "nixos" == "nixos"
-      ) (config.outputs.moduleForMachine);
-      darwinModules = lib.filterAttrs (
-        name: _: inventory.machines.${name}.machineClass or "nixos" == "darwin"
-      ) (config.outputs.moduleForMachine);
-
       inherit inventoryClass;
 
       # Endpoint that can be called to get a service schema

lib/build-clan/public.nix

@@ -14,6 +14,8 @@
   topLevel = [
     "clanInternals"
     "nixosConfigurations"
+    "nixosModules"
     "darwinConfigurations"
+    "darwinModules"
   ];
 }

lib/build-clan/tests.nix

@@ -157,6 +157,24 @@ in
       ];
     };
 
+  test_machines_are_modules =
+    let
+      result = buildClan {
+        self = {
+          inputs = { };
+        };
+        directory = ../../.;
+        meta.name = "test-clan-core";
+      };
+    in
+    {
+      expr = builtins.attrNames result.nixosModules;
+      expected = [
+        "clan-machine-test-backup"
+        "clan-machine-test-inventory-machine"
+      ];
+    };
+
   test_buildClan_all_machines =
     let
       result = buildClan {

lib/clanTest/flake-module.nix

@@ -6,13 +6,14 @@
 }:
 let
   inherit (lib)
+    flatten
+    flip
+    mapAttrs'
+    mapAttrsToList
     mkOption
     removePrefix
     types
-    mapAttrsToList
-    flip
     unique
-    flatten
     ;
 
   clanLib = config.flake.clanLib;
@@ -143,7 +144,12 @@ in
         # Inherit all nodes from the clan
         # i.e. nodes.jon <- clan.machines.jon
         # clanInternals.nixosModules contains nixosModules per node
-        nodes = clanFlakeResult.clanInternals.nixosModules;
+        nodes = flip mapAttrs' clanFlakeResult.nixosModules (
+          name: machineModule: {
+            name = removePrefix "clan-machine-" name;
+            value = machineModule;
+          }
+        );
 
         # !WARNING: Write a detailed comment if adding new options here
         # We should be very careful about adding new options here because it affects all tests

pkgs/clan-cli/clan_cli/tests/test_flake_with_core/flake.nix

@@ -62,6 +62,6 @@
     in
     {
       clan = clan_attrs_json;
-      inherit (clan) nixosConfigurations clanInternals;
+      inherit (clan) nixosConfigurations nixosModules clanInternals;
     };
 }

pkgs/clan-cli/clan_cli/tests/test_flake_with_core_and_pass/flake.nix

@@ -44,6 +44,6 @@
       };
     in
     {
-      inherit (clan) nixosConfigurations clanInternals;
+      inherit (clan) nixosConfigurations nixosModules clanInternals;
     };
 }

pkgs/clan-cli/clan_cli/tests/test_flake_with_core_dynamic_machines/flake.nix

@@ -19,6 +19,6 @@
       };
     in
     {
-      inherit (clan) nixosConfigurations clanInternals;
+      inherit (clan) nixosConfigurations nixosModules clanInternals;
     };
 }

templates/clan/minimal/flake.nix

@@ -10,6 +10,6 @@
     in
     {
       # all machines managed by Clan
-      inherit (clan) nixosConfigurations clanInternals;
+      inherit (clan) nixosConfigurations nixosModules clanInternals;
     };
 }

templates/clan/new-clan/flake.nix

@@ -26,7 +26,7 @@
       };
     in
     {
-      inherit (clan) nixosConfigurations clanInternals;
+      inherit (clan) nixosConfigurations nixosModules clanInternals;
       # Add the Clan cli tool to the dev shell.
       # Use "nix develop" to enter the dev shell.
       devShells =