CompatibleLog for making log_file and log_dir compatible.

GetFileNameDayAndOldDay get name of new file and old file.

GetLastNum get file name number suffix.

Hostname get current hostname.

MyNewLogger constructor of needed logger.

NewConfig the constructor of config.

NewMySQLConnection the constructor of mysql connecting.

BaseConf config about dir, log, etc.

Config for initializing.

DatabaseConf config about database.