LuaLogging: A simple API to use logging features in Lua

LuaLogging Reference Manual

A simple API to use logging features in Lua

Introduction

LuaLogging is a simple API to use logging features in Lua. Its design is based on log4j.

LuaLogging defines one single global variable, a table called logging which holds the function that creates new loggers.

Logger objects

A logger object offers methods that writes log messages. To create a logger you simply call the function:

logging.new (filename)
The parameter filename is the name of the file to be written to. The application must have write permissions to the specified file.
This function returns a logger object.

Methods

logger:log (level, message)
Logs a message with the specified level.
The parameter message may be any lua value, not just strings. The same applies to all the functions below.
logger:debug (message)
Logs a message with DEBUG level.
logger:info (message)
Logs a message with DEBUG level.
logger:warn (message)
Logs a message with DEBUG level.
logger:error (message)
Logs a message with DEBUG level.
logger:fatal (message)
Logs a message with FATAL level.
logger:setLevel (level)
The parameter level is one of the variables enumerated here.

Levels

logging.DEBUG
The DEBUG level designates fine-grained informational events that are most useful to debug an application.
logging.INFO
The INFO level designates informational messages that highlight the progress of the application at coarse-grained level.
logging.WARN
The WARN level designates potentially harmful situations.
logging.ERROR
The ERROR level designates error events that might still allow the application to continue running.
logging.FATAL
The FATAL level designates very severe error events that will presumably lead the application to abort.

Example

Below is a small sample code displaying the basic use of the library.

require "logging"

local logger = logging.new("/tmp/test.log")
logger:setLevel (logging.WARN)

logger:log(logging.INFO, "sending email")

logger:info("trying to contact server")
logger:warn("server did not responded yet")
logger:error("server unreachable")

Upon execution the file "/tmp/test.log" contains the following lines.
Notice that the INFO log requests are not handled because the minimum level is set to WARN.

06/17/04 16:21:15 WARN server did not responded yet
06/17/04 16:21:20 ERROR server unreachable

Appenders