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I have a problem using Log4r.

uninitialized constant Log4r::Logger::RootLogger

I tried this, but still got an error:

>> require "log4r"
=> true
>> Log4r::DEBUG
NameError: uninitialized constant Log4r::DEBUG
>> Log4r::Logger.root
=> uninitialized constant Log4r::Logger::RootLogger
from /var/lib/gems/1.9.1/gems/log4r-1.1.11/lib/log4r/staticlogger.rb:5:in `root'
    from (irb):5
    from /usr/bin/irb:12:in `<main>'
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user2503775
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  • Can you explain why are you using Log4r and what you are trying to accomplish? – Simone Carletti Jan 05 '14 at 14:27
  • I'm using Log4r in my App - for logs. But I see this passenger error in browser - when trying to access my App. – user2503775 Jan 05 '14 at 14:30
  • possible duplicate of [Ruby: Uninitialized constant Log4r::DEBUG (NameError) problem](http://stackoverflow.com/questions/5799823/ruby-uninitialized-constant-log4rdebug-nameerror-problem) – knut Jan 05 '14 at 14:58
  • There is a major change with V1.1.11 (published yesterday), so I would recommend to use the previous version 1.1.10 (see my [answer](http://stackoverflow.com/a/20934944/676874)). I created a [bug report for it](http://rubyforge.org/tracker/index.php?func=detail&aid=29856&group_id=203&atid=851) – knut Jan 05 '14 at 22:43
  • Yesterday I found out what was the problem , since the error was `from /var/lib/gems/1.9.1/gems/log4r-1.1.11`, and this version was released just yesterday, I guessed they have a problem with it. So I forced the previous version, and everything works fine. – user2503775 Jan 06 '14 at 06:30
  • My [bug report](http://rubygems.org/gems/log4r) leads to a roll back of log4r 1.1.11. It is removed from http://rubygems.org/gems/log4r . @user2503775 You could close your question and accept my answer, it contains the correct solution. – knut Jan 08 '14 at 20:22

2 Answers2

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Your problem with Log4r::Logger.root is version depending (the actual version 1.1.11 has this problem).

You may use the previous log4r-version 1.1.10:

gem 'log4r', '<=1.1.10' #or '= 1.1.10'
require 'log4r'
Log4r::Logger.root

log4r defines the constants like Log4r::DEBUG with the creation of the first logger.

You need a Log4r::Logger.new('dummy') before you have access to the level constants.

require 'log4r'

p defined? Log4r::INFO   #false
Log4r::Logger.new('dummy')
p defined? Log4r::INFO   #constant -> is defined

Some background: There is a constant Log4r::Log4rConfig::LogLevels defining the different levels. The level-constants are defined, when the first logger is created. You may define them also with Log4r.define_levels(*Log4r::Log4rConfig::LogLevels)

This technique allows it to create loggers with different logging levels.

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knut
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0

AlthoughLog4r::Logger.root no longer enables the constants, the code included later on in the answer you referred to does introduce the constants:

Log4r.define_levels(*Log4r::Log4rConfig::LogLevels)

per the following:

MacbookAir1:so1 palfvin$ irb
2.0.0p247 :001 > require 'log4r'
 => true 
2.0.0p247 :002 > Log4r.define_levels(*Log4r::Log4rConfig::LogLevels)
 => 5 
2.0.0p247 :003 > Log4r::DEBUG
 => 1 
2.0.0p247 :004 >
Peter Alfvin
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  • Same undefined constant error for accessing `Log4r::DEBUG`? (See updated answer for Ruby version information I'm testing with). – Peter Alfvin Jan 05 '14 at 15:29