build-inventory: move inventory and inventoryClass into explizitly different folders

lib/modules/inventory/frontmatter/default.nix

@@ -0,0 +1,173 @@
+{ lib, clanLib }:
+let
+  # Trim the .nix extension from a filename
+  trimExtension = name: builtins.substring 0 (builtins.stringLength name - 4) name;
+
+  jsonWithoutHeader = clanLib.jsonschema {
+    includeDefaults = true;
+    header = { };
+  };
+
+  getModulesSchema =
+    {
+      modules,
+      clan-core,
+      pkgs,
+    }:
+    lib.mapAttrs
+      (
+        _moduleName: rolesOptions:
+        lib.mapAttrs (_roleName: options: jsonWithoutHeader.parseOptions options { }) rolesOptions
+      )
+      (
+        clanLib.evalClan.evalClanModulesWithRoles {
+          allModules = modules;
+          inherit pkgs clan-core;
+        }
+      );
+
+  evalFrontmatter =
+    {
+      moduleName,
+      instanceName,
+      resolvedRoles,
+      allModules,
+    }:
+    lib.evalModules {
+      modules = [
+        (getFrontmatter allModules.${moduleName} moduleName)
+        ./interface.nix
+        {
+          constraints.imports = [
+            (lib.modules.importApply ../constraints {
+              inherit moduleName resolvedRoles instanceName;
+              allRoles = getRoles "inventory.modules" allModules moduleName;
+            })
+          ];
+        }
+      ];
+    };
+
+  # For Documentation purposes only
+  frontmatterOptions =
+    (lib.evalModules {
+      modules = [
+        ./interface.nix
+        {
+          constraints.imports = [
+            (lib.modules.importApply ../constraints {
+              resolvedRoles = { };
+              moduleName = "{moduleName}";
+              instanceName = "{instanceName}";
+              allRoles = [ "{roleName}" ];
+            })
+          ];
+        }
+      ];
+    }).options;
+
+  migratedModules = [ "admin" ];
+
+  makeModuleNotFoundError =
+    serviceName:
+    if builtins.elem serviceName migratedModules then
+      ''
+        (Legacy) ClanModule not found: '${serviceName}'.
+
+        Please update your configuration to use this module via 'inventory.instances'
+        See: https://docs.clan.lol/guides/clanServices/
+      ''
+    else
+      ''
+        (Legacy) ClanModule not found: '${serviceName}'.
+
+        Make sure the module is added to inventory.modules.${serviceName}
+      '';
+  # This is a legacy function
+  # Old modules needed to define their roles by directory
+  # This means if this function gets anything other than a string/path it will throw
+  getRoles =
+    _scope: allModules: serviceName:
+    let
+      module = allModules.${serviceName} or (throw (makeModuleNotFoundError serviceName));
+      moduleType = (lib.typeOf module);
+      checked =
+        if
+          builtins.elem moduleType [
+            "string"
+            "path"
+          ]
+        then
+          true
+        else
+          throw "(Legacy) ClanModule must be a 'path' or 'string' pointing to a directory: Got 'typeOf inventory.modules.${serviceName}' => ${moduleType} ";
+      modulePath = lib.seq checked module + "/roles";
+      checkedPath =
+        if builtins.pathExists modulePath then
+          modulePath
+        else
+          throw ''
+            (Legacy) ClanModule must have a 'roles' directory'
+
+            Fixes:
+            - Provide a 'roles' subdirectory
+            - Use the newer 'clan.service' modules. (Recommended)
+          '';
+    in
+    lib.seq checkedPath lib.mapAttrsToList (name: _value: trimExtension name) (
+      lib.filterAttrs (name: type: type == "regular" && lib.hasSuffix ".nix" name) (
+        builtins.readDir (checkedPath)
+      )
+    );
+
+  checkConstraints = args: (evalFrontmatter args).config.constraints.assertions;
+
+  getReadme =
+    modulepath: modulename:
+    let
+      readme = modulepath + "/README.md";
+      readmeContents =
+        if (builtins.pathExists readme) then
+          (builtins.readFile readme)
+        else
+          throw "No README.md found for module ${modulename} (expected at ${readme})";
+    in
+    readmeContents;
+
+  getFrontmatter =
+    modulepath: modulename:
+    let
+      content = getReadme modulepath modulename;
+      parts = lib.splitString "---" content;
+      # Partition the parts into the first part (the readme content) and the rest (the metadata)
+      parsed = builtins.partition ({ index, ... }: if index >= 2 then false else true) (
+        lib.filter ({ index, ... }: index != 0) (lib.imap0 (index: part: { inherit index part; }) parts)
+      );
+      meta = builtins.fromTOML (builtins.head parsed.right).part;
+    in
+    if (builtins.length parts >= 3) then
+      meta
+    else
+      throw ''
+        TOML Frontmatter not found in README.md for module ${modulename}
+
+        Please add the following to the top of your README.md:
+
+        ---
+        description = "Your description here"
+        categories = [ "Your categories here" ]
+        features = [ "inventory" ]
+        ---
+        ...rest of your README.md...
+      '';
+in
+{
+  inherit
+    frontmatterOptions
+    getModulesSchema
+    getFrontmatter
+
+    checkConstraints
+    getRoles
+    ;
+}