+ * LOG_LEVEL=DEBUG or INFO or WARNING or ERROR or FATAL
+ (select log level to print, LOGGING option should be true)
+ default is debug level with no private log.
+ ex) LOG_LEVEL=DEBUG : All logs including DEBUG, INFO, WARNING, ERROR, FATAL level is printed.
+ and private log is disabled.
+ LOG_LEVEL=INFO : The logs including INFO, WARNING, ERROR, FATAL level is printed.
+ and private log is disabled.
+ LOG_LEVEL=WARNING : The logs including WARNING, ERROR, FATAL level is printed.
+ LOG_LEVEL=ERROR : The logs including ERROR, FATAL level is printed.
+ LOG_LEVEL=FATAL : FATAL level is printed.