Logging

by Tim Pease

• Homepage

• Github Project

• email tim dot pease at gmail dot com

DESCRIPTION

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.

INSTALL

gem install logging

EXAMPLE

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:

• simple.rb

• loggers.rb

• classes.rb

• hierarchies.rb

• names.rb

• appenders.rb

• layouts.rb

• formatting.rb

• colorization.rb

• consolidation.rb

• fork.rb

NOTES

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 – Logging vs. Log4r. Other differences include renaming Log4r::Outputter to Logging::Appender and renaming Log4r::Formatter to Logging::Layout. These changes were meant to bring the Logging class names more in line with the Log4j class names.

REQUIREMENTS

The Logging source code relies on the Mr Bones project for default rake tasks. You will need to install the Mr Bones gem if you want to build or test the logging gem.

gem install bones

After Mr Bones is installed you can install all the depdencies via the rake task.

rake gem:install_dependencies

Always remember that “rake -T” is your friend!

LICENSE

Ruby