Rolling File appender
The rolling file appender can be used to write log messages to a file. It uses Lua I/O routines to do its job. The rolling file appender rolls over the logfile once it has reached a certain size limit. It also mantains a maximum number of log files.
function logging.rolling_file(filename, maxFileSize, [maxBackupIndex], [logPattern])
- filename:
 The name of the file to be written to.
 If the file cannot be opened for appending the logging request returns nil and an error message.
- maxFileSize:
 The max size of the file in bytes. Every time the file reaches this size it will rollover, generating a new clean log file and storing the old log on a filename.n, where n goes from 1 to the configured maxBackupIndex.
 The more recent backup is the one with the lowest n on its filename.
 Eg. test.log.1 (most recent backup)
 test.log.2 (least recent backup)
- maxBackupIndex:
 The number of backup files that will be generated. The default value is- 1.
- logPattern:
 A pattern can be specified to control how the message is written.
 The default value is- "%date %level %message\n".
Example
require"logging.rolling_file"
local logger = logging.rolling_file("test.log", 1024, 5, "%Y-%m-%d")
logger:info("logging.file test")
logger:debug("debugging...")
logger:error("error!")
