Yell - Your Extensible Logging Library
Yell works and is tested with ruby 1.8.7, 1.9.x, jruby 1.8 and 1.9 mode, rubinius 1.8 and 1.9 as well as ree.
If you want to use Yell with Rails, then head over to yell-rails.
Installation
System wide:
gem install yell
Or in your Gemfile:
gem "yell"
Usage
On the basics, you can use Yell just like any other logging library with a more sophisticated message formatter.
logger = Yell.new STDOUT
logger.info "Hello World"
#=> "2012-02-29T09:30:00+01:00 [ INFO] 65784 : Hello World"
# ^ ^ ^ ^
# ISO8601 Timestamp Level Pid Message
The strength of Yell, however, comes when using multiple adapters. The already built-in ones are IO-based and require no further configuration. Also, there are additional ones available as separate gems. Please consult the wiki on that - they are listed there.
The standard adapters are:
:stdout
: Messages will be written to STDOUT
:stderr
: Messages will be written to STDERR
:file
: Messages will be written to a file
:datefile
: Messages will be written to a timestamped file
Here are some short examples on how to combine them:
Example: Notice messages go into STDOUT
and error messages into STDERR
logger = Yell.new do |l|
l.adapter STDOUT, :level => [:debug, :info, :warn]
l.adapter STDERR, :level => [:error, :fatal]
end
Example: Typical production Logger
We setup a logger that starts passing messages at the :info
level. Severities
below :error
go into the 'production.log', whereas anything higher is written
into the 'error.log'.
logger = Yell.new do |l|
l.level = :info # will only pass :info and above to the adapters
l.adapter :datefile, 'production.log', :level => Yell.level.lte(:warn)
l.adapter :datefile, 'error.log', :level => Yell.level.gte(:error)
end
Further Readings
How To: Setting The Log Level
How To: Formatting Log Messages
How To: Using Adapters
How To: The Datefile Adapter
How To: Different Adapters for Different Log Levels
Additional Adapters
Development
How To: Writing Your Own Adapter
You can find further examples and additional adapters in the wiki. or have a look into the examples folder.
Copyright © 2011-2012 Rudolf Schmidt, released under the MIT license