Add basic systemd service to build configs

flake.nix

@@ -82,6 +82,7 @@
         nix.extraOptions = ''
           experimental-features = nix-command flakes
         '';
+        nixpkgs.overlays = [ (self: super: { nix = super.nixUnstable; }) ];
       };
 
       # Some basics that every machine should have
@@ -193,6 +194,7 @@
           self.nixosModules.x86_64-linux-basics
           ./hosts/elysia-clarki.nix
           ./hardware/intel-nuc.nix
+          ./modules/local-build-service.nix
           #./modules/nginx-reverse-proxy.nix
           #./modules/binary-cache.nix
 

modules/local-build-service.nix

@@ -0,0 +1,42 @@
+{ pkgs, ... }:
+
+let
+  targetHosts = [ "helix-texta" "elysia-clarki" ];
+
+  remote = "https://git.sr.ht/~megamanmalte/nixos";
+
+  buildForHost = host:
+    with pkgs; ''
+      nixos-rebuild build --flake .#${host} || exit 1
+    '';
+
+  build = with pkgs;
+    writeScriptBin "build" ''
+      #!${stdenv.shell}
+
+      rm -rf nixos
+      git clone ${remote} || exit 2
+      cd nixos
+      ${builtins.concatStringsSep "\n" (map buildForHost targetHosts)}
+      rm result
+    '';
+
+in {
+  systemd.services.local-build-service = {
+    unitConfig = {
+      Description = ''
+        Regularly pull and build various configuration to populate the local store
+      '';
+      After = [ "network.target" ];
+    };
+    serviceConfig = {
+      Type = "oneshot";
+      ExecStart = [ "${build}/bin/build" ];
+      RuntimeDirectory = "local-build-service";
+      CacheDirectory = "local-build-service";
+      CacheDirectoryMode = "0777";
+      Environment = with pkgs;
+        "PATH=${git}/bin:${coreutils}/bin:${nixos-rebuild}/bin";
+    };
+  };
+}