Extract duplicated nix configuration

lib/builders/mkNixDarwin.nix

@@ -8,6 +8,7 @@ inputs.darwin.lib.darwinSystem {
   };
 
   modules = [
+    ./modules/nix
     inputs.home-manager.darwinModules.home-manager
     "${inputs.self}/hosts/${name}"
 

lib/builders/mkNixos.nix

@@ -8,6 +8,7 @@ inputs.nixpkgs.lib.nixosSystem {
   };
 
   modules = [
+    ./modules/nix
     "${inputs.self}/hosts/${name}"
 
     {

lib/builders/modules/nix/default.nix

@@ -0,0 +1,36 @@
+{ pkgs, config, lib, inputs, ... }:
+
+{
+  nix = {
+    nixPath = [ "nixpkgs=flake:nixpkgs" ];
+    registry = {
+      nixpkgs.flake = inputs.nixpkgs;
+      nix-config.flake = inputs.self;
+    };
+    settings = {
+      allowed-users = builtins.attrNames config.users.users;
+      auto-optimise-store = true;
+      experimental-features = [ "nix-command" "flakes" ];
+      log-lines = 30;
+      substituters = [
+        "https://christianharke.cachix.org/"
+        "https://nix-community.cachix.org"
+        "https://cache.nixos.org"
+      ];
+      trusted-public-keys = [
+        "christianharke.cachix.org-1:TzmbiNLRcH8G0932XRlQzh8GPvuV9pJcHLqLnzznLKU="
+        "nix-community.cachix.org-1:mB9FSh9qf2dCimDSUo8Zy7bkq5CX+/rkCWyvRCYg3Fs="
+        "cache.nixos.org-1:6NCHdD59X431o0gWypbMrAURkbJ16ZPMQFGspcDShjY="
+      ];
+    };
+  };
+
+  system.activationScripts.diff = {
+    supportsDryActivation = true;
+    text = ''
+      if [[ -e /run/current-system ]]; then
+         ${lib.getExe pkgs.nix} store diff-closures /run/current-system "$systemConfig"
+      fi
+    '';
+  };
+}

nix-darwin/nix/default.nix

@@ -1,37 +1,9 @@
 { pkgs, config, lib, inputs, ... }:
 
 {
-  # TODO: Extract duplications from nixos config
   nix = {
-    nixPath = [ "nixpkgs=flake:nixpkgs" ];
-    registry = {
-      nixpkgs.flake = inputs.nixpkgs;
-      nix-config.flake = inputs.self;
-    };
     settings = {
-      allowed-users = builtins.attrNames config.users.users;
       auto-optimise-store = true;
-      experimental-features = [ "nix-command" "flakes" ];
-      log-lines = 30;
-      substituters = [
-        "https://christianharke.cachix.org/"
-        "https://nix-community.cachix.org"
-        "https://cache.nixos.org"
-      ];
-      trusted-public-keys = [
-        "christianharke.cachix.org-1:TzmbiNLRcH8G0932XRlQzh8GPvuV9pJcHLqLnzznLKU="
-        "nix-community.cachix.org-1:mB9FSh9qf2dCimDSUo8Zy7bkq5CX+/rkCWyvRCYg3Fs="
-        "cache.nixos.org-1:6NCHdD59X431o0gWypbMrAURkbJ16ZPMQFGspcDShjY="
-      ];
     };
   };
-
-  system.activationScripts.diff = {
-    supportsDryActivation = true;
-    text = ''
-      if [[ -e /run/current-system ]]; then
-         ${lib.getExe pkgs.nix} store diff-closures /run/current-system "$systemConfig"
-      fi
-    '';
-  };
 }

nixos/base/nix/default.nix

@@ -7,35 +7,6 @@
       dates = "04:00";
       options = "--delete-older-than 7d";
     };
-    nixPath = [ "nixpkgs=flake:nixpkgs" ];
     optimise.automatic = true;
-    registry = {
-      nixpkgs.flake = inputs.nixpkgs;
-      nix-config.flake = inputs.self;
-    };
-    settings = {
-      allowed-users = builtins.attrNames config.users.users;
-      experimental-features = [ "nix-command" "flakes" ];
-      log-lines = 30;
-      substituters = [
-        "https://christianharke.cachix.org/"
-        "https://nix-community.cachix.org"
-        "https://cache.nixos.org"
-      ];
-      trusted-public-keys = [
-        "christianharke.cachix.org-1:TzmbiNLRcH8G0932XRlQzh8GPvuV9pJcHLqLnzznLKU="
-        "nix-community.cachix.org-1:mB9FSh9qf2dCimDSUo8Zy7bkq5CX+/rkCWyvRCYg3Fs="
-        "cache.nixos.org-1:6NCHdD59X431o0gWypbMrAURkbJ16ZPMQFGspcDShjY="
-      ];
-    };
-  };
-
-  system.activationScripts.diff = {
-    supportsDryActivation = true;
-    text = ''
-      if [[ -e /run/current-system ]]; then
-         ${lib.getExe pkgs.nix} store diff-closures /run/current-system "$systemConfig"
-      fi
-    '';
   };
 }