nixos/stalwart-mail: support adding secrets (#380588)

        Data directory for stalwart

      '';

    };

    credentials = lib.mkOption {

      description = ''

        Credentials envs used to configure Stalwart-Mail secrets.

        These secrets can be accessed in configuration values with

        the macros such as

        `%{file:/run/credentials/stalwart-mail.service/VAR_NAME}%`.

      '';

      type = lib.types.attrsOf lib.types.str;

      default = { };

      example = {

        user_admin_password = "/run/keys/stalwart_admin_password";

      };

    };

  };

  config = lib.mkIf cfg.enable {

            ""

            "${cfg.package}/bin/stalwart-mail --config=${configFile}"

          ];

          LoadCredential = lib.mapAttrsToList (key: value: "${key}:${value}") cfg.credentials;

          StandardOutput = "journal";

          StandardError = "journal";