nixos/miniflux: don't require DATABASE_URL if not createDatabaseLocally (#466325)

              example = "127.0.0.1:8080, 127.0.0.1:8081";

            };

            DATABASE_URL = mkOption {

              type = types.str;

              defaultText = "user=miniflux host=/run/postgresql dbname=miniflux";

              type = types.nullOr types.str;

              defaultText = literalExpression ''

                if createDatabaseLocally then "user=miniflux host=/run/postgresql dbname=miniflux" else null

              '';

              default =

                if cfg.createDatabaseLocally then "user=miniflux host=/run/postgresql dbname=miniflux" else null;

              description = ''

                Postgresql connection parameters.

                See [lib/pq](https://pkg.go.dev/github.com/lib/pq#hdr-Connection_String_Parameters) for more details.

        message = "services.miniflux.adminCredentialsFile must be set if services.miniflux.config.CREATE_ADMIN is 1";

      }

    ];

    services.miniflux.config = {

      DATABASE_URL = lib.mkIf cfg.createDatabaseLocally "user=miniflux host=/run/postgresql dbname=miniflux";

    };

    services.postgresql = lib.mkIf cfg.createDatabaseLocally {

      enable = true;

        UMask = "0077";

      };

      environment = lib.mapAttrs (_: toString) cfg.config;

      environment = lib.mapAttrs (_: toString) (lib.filterAttrs (_: v: v != null) cfg.config);

    };

    environment.systemPackages = [ cfg.package ];