flags:
-log.age int
MaxAge is the maximum number of days to retain old log files based on the timestamp encoded in their filename. (default 7)
-log.backups int
MaxBackups is the maximum number of old log files to retain. (default 5)
-log.filename string
log file name (default "default")
-log.level string
log levels:debug/info/warn/error/dpanic/panic/fatal (default "info")
-log.path string
log save path (default "/tmp")
-log.size int
MaxSize is the maximum size in megabytes of the log file before it gets rotated. It defaults to 10 megabytes. (default 10)