inventory: allow per role configuration

lib/inventory/build-inventory/default.nix

@@ -83,6 +83,11 @@ let
               else
                 throw "Module doesn't have role: '${role}'. Path: ${path} not found."
             ) inverseRoles.${machineName} or [ ];
+
+            roleServiceConfigs = builtins.map (
+              role:
+              serviceConfig.roles.${role}.config or { }
+            ) inverseRoles.${machineName} or [ ];
           in
           if isInService then
             acc2
@@ -92,6 +97,7 @@ let
                 config.clan.${moduleName} = lib.mkMerge [
                   globalConfig
                   machineServiceConfig
+                  roleServiceConfigs
                 ];
               }
               {

lib/inventory/build-inventory/interface.nix

@@ -94,6 +94,7 @@ in
                     apply = lib.unique;
                     type = t.listOf tagRef;
                   };
+                  options.config = moduleConfig;
                 }
               );
             };