code: private void createLogger(final String flowId) {
      // Create logger
      final String loggerName = this.execId + "." + flowId;
      this.logger = Logger.getLogger(loggerName);
  
      // Create file appender
      final String logName = "_flow." + loggerName + ".log";
      this.logFile = new File(this.execDir, logName);
      final String absolutePath = this.logFile.getAbsolutePath();
  
      this.flowAppender = null;
      try {
        this.flowAppender = new FileAppender(this.loggerLayout, absolutePath, false);
        this.logger.addAppender(this.flowAppender);
      } catch (final IOException e) {
        this.logger.error("Could not open log file in " + this.execDir, e);
      }
    }
docs: setup logger and execution dir for the flowId