PoC working SP module system

+ simple-nixos-mailserver as an SP module

flake.nix

@@ -9,40 +9,54 @@
     selfprivacy-graphql-api.inputs.nixpkgs.follows = "nixpkgs";
   };
 
-  outputs = { self, nixpkgs, selfprivacy-graphql-api }:
-    let
-      system = "x86_64-linux";
-    in
-    {
-      nixosConfigurations-fun =
-        { hardware-configuration
-        , userdata
-        , top-level-flake
-        }: {
-          just-nixos = nixpkgs.lib.nixosSystem {
-            specialArgs = {
-              inherit
-                system
-                hardware-configuration
-                userdata;
-              selfprivacy-graphql-api =
-                selfprivacy-graphql-api.packages.${system}.default;
-            };
-            modules = [
-              hardware-configuration
-              ./configuration.nix
-              {
-                # embed top-level flake source folder into the build
-                environment.etc."selfprivacy-config-source" =
-                  top-level-flake.outPath;
-                # for running "nix search nixpkgs", etc
-                nix.registry.nixpkgs.flake = nixpkgs;
-                # embed commit sha1; dirty builds are intentionally forbidden
-                system.configurationRevision = self.rev;
-              }
-            ];
-            inherit system;
-          };
+  outputs = { self, nixpkgs, selfprivacy-graphql-api }: {
+    nixosConfigurations-fun =
+      { system
+      , hardware-configuration
+      , userdata
+      , top-level-flake
+      , sp-modules
+      }:
+      let
+        lib = nixpkgs.legacyPackages.${system}.lib;
+      in
+      {
+        inherit system;
+        just-nixos = nixpkgs.lib.nixosSystem {
+          specialArgs = { inherit system; };
+          modules = [
+            hardware-configuration
+            ./configuration.nix
+            (import ./userdata-variables.nix userdata)
+            (import ./api/api-module.nix
+              selfprivacy-graphql-api.packages.${system}.default)
+            {
+              # embed top-level flake source folder into the build
+              environment.etc."selfprivacy-config-source".source =
+                top-level-flake.outPath;
+              # for running "nix search nixpkgs", etc
+              nix.registry.nixpkgs.flake = nixpkgs;
+              # embed commit sha1; FIXME dirty builds must be intentionally forbidden
+              system.configurationRevision = self.rev or ("#" + self.lastModifiedDate + "-" + toString self.lastModified);
+            }
+          ]
+          ++
+          # add SP modules, but filter available config attributes for each
+          map
+            (sp-module: args@{ pkgs, ... }: (sp-module.nixosModules.default
+              (args // {
+                config =
+                  # TODO use lib.attrsets.mergeAttrsList from nixpkgs 23.05
+                  (builtins.foldl' lib.trivial.mergeAttrs { }
+                    (map
+                      (p: lib.attrsets.setAttrByPath p
+                        (lib.attrsets.getAttrFromPath p args.config))
+                      sp-module.configPathsNeeded));
+              }))
+            )
+            # (sp-module: sp-module.nixosModules.default)
+            (lib.attrsets.attrValues sp-modules);
         };
-    };
+      };
+  };
 }