LuaLogging: A simple API to use logging features in Lua

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 = string,]
    maxFileSize = number,
    [maxBackupIndex = number,]

    [logPattern = string,]
    [logPatterns = {
      [logging.DEBUG = string,]
      [logging.INFO  = string,]
      [logging.WARN  = string,]
      [logging.ERROR = string,]
      [logging.FATAL = string,]
    },]
    [timestampPattern = string,]
    [logLevel = log-level-constant,]
}

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.
The default value is "lualogging.log".
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.
logPatterns:
A table with logPattern strings indexed by the log-levels. A logPattern specifies how the message is written.
If this parameter is omitted, a patterns table will be created with the parameter logPattern as the default value for each log-level. If logPattern also is omitted then each level will fall back to the current default setting, see logging.defaultLogPatterns.
logPattern:
This value will be used as the default value for each log-level that was omitted in logPatterns.
timestampPattern:
This is an optional parameter that can be used to specify a date/time formatting in the log message. See logging.date for the format. The default is taken from logging.defaultTimestampPattern().
logLevel:
The initial log-level to set for the created logger.

Example

require"logging.rolling_file"

local logger = logging.rolling_file {
    filename = "test.log",
    maxFileSize = 1024,
    maxBackupIndex = 5,
}

logger:info("logging.rolling_file test")
logger:debug("debugging...")
logger:error("error!")