Kreps

Kreps makes it easy to use Log4j, Logback or any SLF4J compatible Java logger library through a Ruby standard library Logger interface.

JRuby 1.7.x.

Kreps is available from RubyGems and can be installed by adding the following line to your application's Gemfile:

gem 'kreps'

Or directly from RubyGems:

$ gem install kreps

require 'kreps'

logger = Kreps.logger('MyLogger')
logger.info('hello world')

By default Kreps uses SLF4J's "simple" implementation, but you can change the SLF4J backend by using require 'kreps/silent', require 'kreps/jdk' or require 'kreps/custom' instead of require 'kreps'.

The default logger backend, SLF4J's "simple" prints all messages at the info level and above to stderr, but this can be configured.

The "nop" backend, enabled with require 'kreps/silent', simply turns off logging completely, which can be useful in some situations, for example when running tests.

The "jdk14" backend, enabled with require 'kreps/jdk', uses Java's built in logging framework, see java.util.logging.Logger).

require 'kreps/jdk'

logger = Kreps.logger('MyLogger')
logger.info('hello world')

SLF4J ships with two more bridges, but they require additional libraries to be available and for that reason don't have any short cuts in Kreps. You can enable them by setting the $KREPS_BACKEND global before require 'kreps', but make sure you also load their JARs. These bridges are "jcl" (for Java Commons Logging) and "log4j12" (for Log4j 1.2, probably the most widely used logging library in the Java world).

There are also logging libraries that come with their own SLF4J adapters, such as Logback and Log4j 2, both successors to Log4j 1.2 in some form or another.

To use these you can require 'kreps/custom' instead of just require 'kreps', or you can set $KREPS_BACKEND to nil before require 'kreps'. Make sure you load the library's JARs.

require 'kreps/custom'
require 'log4j-api-2.0-rc1.jar'
require 'log4j-core-2.0-rc1.jar'
require 'log4j-slf4j-impl-2.0-rc1.jar'

logger = Kreps.logger('MyLogger')
logger.info('hello world')

See CONTRIBUTING.md

© 2014 Theo Hultberg, see LICENSE.txt (BSD 3-Clause).