anchor.diff:  
         redisUrl = mkOption {
           type = types.str;
  -        default = "redis://localhost:${toString config.services.redis.servers.gitlab.port}/";
  -        defaultText = literalExpression ''redis://localhost:''${toString config.services.redis.servers.gitlab.port}/'';
  -        description = lib.mdDoc "Redis URL for all GitLab services except gitlab-shell";
  +        default = "unix:/run/gitlab/redis.sock";
  +        example = "redis://localhost:6379/";
  +        description = lib.mdDoc "Redis URL for all GitLab services.";
         };
   
         extraGitlabRb = mkOption {
  
positive.code:     # Redis is required for the sidekiq queue runner.
      services.redis.servers.gitlab = {
        enable = mkDefault true;
        port = mkDefault 31636;
        bind = mkDefault "127.0.0.1";
      };
  
      # We use postgres as the main data store.
  
negative.code:     repos_path = "${cfg.statePath}/repositories";
      secret_file = "${cfg.statePath}/gitlab_shell_secret";
      log_file = "${cfg.statePath}/log/gitlab-shell.log";
    };
  
    redisConfig.production.url = cfg.redisUrl;
  