Path: | README.rdoc |
Last Update: | Wed May 15 19:17:52 +0000 2013 |
Logging is a flexible logging library for use in Ruby programs based on the design of Java‘s log4j library. It features a hierarchical logging system, custom level names, multiple output destinations per log event, custom formatting, and more.
gem install logging
This example configures a logger to output messages in a format similar to the core ruby Logger class. Only log messages that are warnings or higher will be logged.
require 'logging' logger = Logging.logger(STDOUT) logger.level = :warn logger.debug "this debug message will not be output by the logger" logger.warn "this is your last warning"
In this example, a single logger is created that will append to STDOUT and to a file. Only log messages that are informational or higher will be logged.
require 'logging' logger = Logging.logger['example_logger'] logger.add_appenders( Logging.appenders.stdout, Logging.appenders.file('example.log') ) logger.level = :info logger.debug "this debug message will not be output by the logger" logger.info "just some friendly advice"
The Logging library was created to allow each class in a program to have its own configurable logger. The logging level for a particular class can be changed independently of all other loggers in the system. This example shows the recommended way of accomplishing this.
require 'logging' Logging.logger['FirstClass'].level = :warn Logging.logger['SecondClass'].level = :debug class FirstClass def initialize @logger = Logging.logger[self] end def some_method @logger.debug "some method was called on #{self.inspect}" end end class SecondClass def initialize @logger = Logging.logger[self] end def another_method @logger.debug "another method was called on #{self.inspect}" end end
There are many more examples in the "examples" folder of the logging package. The recommended reading order is the following:
Although Logging is intended to supersede Log4r, it is not a one-to-one replacement for the Log4r library. Most notably is the difference in namespaces