fix: use caddy module from nixos-unstable

flake.nix

@@ -92,6 +92,8 @@
             };
           };
 
+          checks = builtins.mapAttrs (system: deployLib: deployLib.deployChecks self.deploy) inputs.deploy-rs.lib;
+
           nixosModules = {
             # Common nixos/nix-darwin configuration shared between Linux and macOS.
             common = { pkgs, ... }: {

lib/deploy.nix

@@ -6,10 +6,13 @@
  */
 
 { lib, inputs }: let
+  # https://github.com/serokell/deploy-rs#overall-usage
+  system = "x86_64-linux";
+  pkgs = import inputs.nixpkgs { inherit system; };
   deployPkgs = import inputs.nixpkgs {
     inherit system;
     overlays = [
-      deploy-rs.overlay
+      inputs.deploy-rs.overlay
       (self: super: { deploy-rs = { inherit (pkgs) deploy-rs; lib = super.deploy-rs.lib; }; })
     ];
   };