anchor.diff:  { config, lib, pkgs, ... }:
   
  -let cfg = config.services.hydron;
  +let
  +  cfg = config.services.hydron;
  +  postgres = config.services.postgresql;
   in with lib; {
     options.services.hydron = {
       enable = mkEnableOption "hydron";
  
positive.code:   };
  
    config = mkIf cfg.enable {
      systemd.services.hydron = {
        description = "hydron";
        after = [ "network.target" ];
        wantedBy = [ "multi-user.target" ];
  
        preStart = ''
          # Ensure folder exists and permissions are correct
          mkdir -p ${escapeShellArg cfg.dataDir}/images
          chmod 750 ${escapeShellArg cfg.dataDir}
          chown -R hydron:hydron ${escapeShellArg cfg.dataDir}
        '';
  
        serviceConfig = {
  
negative.code:       '';
      };
  
      password = mkOption {
        type = types.str;
        default = "hydron";
        example = "dumbpass";
        description = "Password for the hydron database.";
      };
  
      passwordFile = mkOption {
        type = types.path;
        default = "/run/keys/hydron-password-file";
        example = "/home/okina/hydron/keys/pass";
        description = "Password file for the hydron database.";
      };
  
      postgresArgs = mkOption {
        type = types.str;
        description = "Postgresql connection arguments.";
        example = ''
          {
            "driver": "postgres",
            "connection": "user=hydron password=dumbpass dbname=hydron sslmode=disable"
          }
        '';
      };
  
      postgresArgsFile = mkOption {
        type = types.path;
        default = "/run/keys/hydron-postgres-args";
        example = "/home/okina/hydron/keys/postgres";
        description = "Postgresql connection arguments file.";
      };
  
      listenAddress = mkOption {
        type = types.nullOr types.str;
        default = null;
  