code: public static String getDirName(Props props) {
      String dirSuffix = props.get(CommonJobProperties.NESTED_FLOW_PATH);
  
      if ((dirSuffix == null) || (dirSuffix.length() == 0)) {
        dirSuffix = props.get(CommonJobProperties.JOB_ID);
        if ((dirSuffix == null) || (dirSuffix.length() == 0)) {
          throw new RuntimeException("azkaban.flow.nested.path and azkaban.job.id were not set");
        }
      }
  
      return "_resources_" + dirSuffix.replace(':', '_');
    }
docs: For classpath reasons, we'll put each link file in a separate directory.
  This must be called only after the job id has been inserted by the job.
  
  @param props The Azkaban properties