anchor.diff:  
           cp ${elasticsearchYml} ${configDir}/elasticsearch.yml
           # Make sure the logging configuration for old elasticsearch versions is removed:
  -        rm -f ${if es5 then "${configDir}/logging.yml" else "${configDir}/log4j2.properties"}
  +        rm -f "${configDir}/logging.yml"
           cp ${loggingConfigFile} ${configDir}/${loggingConfigFilename}
  -        ${optionalString es5 "mkdir -p ${configDir}/scripts"}
  +        mkdir -p ${configDir}/scripts
           ${optionalString es6 "cp ${cfg.package}/config/jvm.options ${configDir}/jvm.options"}
   
           if [ "$(id -u)" = 0 ]; then chown -R elasticsearch:elasticsearch ${cfg.dataDir}; fi
  
positive.code: 
      logging = mkOption {
        description = "Elasticsearch logging configuration.";
        default =
          if es5 then ''
            logger.action.name = org.elasticsearch.action
            logger.action.level = info
  
            appender.console.type = Console
            appender.console.name = console
            appender.console.layout.type = PatternLayout
            appender.console.layout.pattern = [%d{ISO8601}][%-5p][%-25c{1.}] %marker%m%n
  
            rootLogger.level = info
            rootLogger.appenderRef.console.ref = console
          '' else ''
            rootLogger: INFO, console
            logger:
              action: INFO
              com.amazonaws: WARN
            appender:
              console:
                type: console
                layout:
                  type: consolePattern
                  conversionPattern: "[%d{ISO8601}][%-5p][%-25c] %m%n"
          '';
        type = types.str;
      };
  
  
negative.code: let
    cfg = config.services.elasticsearch;
  
    es6 = builtins.compareVersions (builtins.parseDrvName cfg.package.name).version "6" >= 0;
  
    esConfig = ''
      network.host: ${cfg.listenAddress}
      cluster.name: ${cfg.cluster_name}
  
      http.port: ${toString cfg.port}
      transport.tcp.port: ${toString cfg.tcp_port}
  
      ${cfg.extraConf}
    '';
  