flake.nix: Centralize overlays

flake.nix

@@ -35,6 +35,7 @@
   outputs = { self, nixpkgs, nixos-hardware, chaosevents, fernglas, nixos-exporter, solid-xmpp-alarm, ssh-to-age, ... }@inputs: let
     lib = import ./lib inputs;
     helper = lib.flake-helper;
+    localNixpkgs = import ./flake/nixpkgs.nix inputs;
   in {
     clerie.hosts = {
       aluminium = {
@@ -93,30 +94,18 @@
 
     colmena = {
       meta = {
-        nixpkgs = import nixpkgs {
-          system = "x86_64-linux";
-        };
+        nixpkgs = localNixpkgs.x86_64-linux;
       };
     } // helper.mapToColmenaHosts self.nixosConfigurations;
 
     overlays = {
+      nixfilesInputs = import ./flake/overlay.nix inputs;
       clerie = import ./pkgs/overlay.nix;
       default = self.overlays.clerie;
     };
 
     packages = nixpkgs.lib.genAttrs [ "x86_64-linux" "aarch64-linux" ] (system: let
-      pkgs = import nixpkgs {
-        inherit system;
-        overlays = [
-          self.overlays.clerie
-          (_: _: {
-            inherit (chaosevents.packages.${system})
-              chaosevents;
-            inherit (ssh-to-age.packages.${system})
-              ssh-to-age;
-           })
-        ];
-      };
+      pkgs = localNixpkgs.${system};
     in {
       inherit (pkgs)
         clerie-keys

flake/nixpkgs.nix

@@ -0,0 +1,17 @@
+{ self
+, nixpkgs
+, ...
+}@inputs:
+
+let
+  mkNixpkgs = { system, ... }@args: 
+    import nixpkgs {
+      inherit system;
+      overlays = [
+        self.overlays.nixfilesInputs
+        self.overlays.clerie
+      ];
+    };
+
+in
+  nixpkgs.lib.genAttrs [ "x86_64-linux" "aarch64-linux" ] (system: mkNixpkgs { inherit system; })

flake/overlay.nix

@@ -0,0 +1,14 @@
+{ self
+, bij
+, chaosevents
+, ssh-to-age
+, ...
+}@inputs:
+final: prev: {
+  inherit (bij.packages.${final.system})
+    bij;
+  inherit (chaosevents.packages.${final.system})
+    chaosevents;
+  inherit (ssh-to-age.packages.${final.system})
+    ssh-to-age;
+}

lib/flake-helper.nix

@@ -1,4 +1,4 @@
-{ self, nixpkgs, bij, chaosevents, fernglas, fieldpoc, nixos-exporter, solid-xmpp-alarm, sops-nix, ... }@inputs:
+{ self, nixpkgs, fernglas, fieldpoc, nixos-exporter, solid-xmpp-alarm, sops-nix, ... }@inputs:
 
 rec {
   generateNixosSystem = {
@@ -26,13 +26,8 @@ rec {
       ../users/clerie
       ({ ... }: {
         nixpkgs.overlays = [
+          self.overlays.nixfilesInputs
           self.overlays.clerie
-          (_: _: {
-            inherit (bij.packages."${system}")
-              bij;
-            inherit (chaosevents.packages."x86_64-linux")
-              chaosevents;
-           })
         ];
         clerie.monitoring = nixpkgs.lib.attrsets.optionalAttrs (group != null) { serviceLevel = group; };
       })