a really threadsafe! (buffered) logger

thread_safe_logger.rb

require 'thread'
require 'active_support/buffered_logger'

# ActiveSupport::BufferedLogger is not completely thread-safe !
# well it is if you disable the silencer :
#
#   ActiveSupport::BufferedLogger.silencer = false
#
# yet Rails might still re-invent the silencing logic and set the
# `logger.level = Logger::ERROR` by hand instead of delegating to
# `logger.silence` ... if you'd like to use `logger.silence {  }` 
# without permanently changing the level if 2 threads perform 
# silencing at the same time you do need a thread-safe logger ...
class ThreadSafeLogger < ActiveSupport::BufferedLogger

  def level
    Thread.current[thread_hash_level_key] || @level
  end

  def level=(level)
    if @level == level
      Thread.current[thread_hash_level_key] = nil
    else
      Thread.current[thread_hash_level_key] = level
    end
    level
  end

  # now override where ActiveSupport::BufferedLogger uses @level :

  def add(severity, message = nil, progname = nil, &block)
    return if level > severity
    message = (message || (block && block.call) || progname).to_s
    message = "#{message}\n" unless message[-1] == ?\n
    buffer << message
    auto_flush
    message
  end

  for severity in Severity.constants
    class_eval <<-EOT, __FILE__, __LINE__ + 1
      def #{severity.downcase}?                # def debug?
        #{severity} >= level                   #   DEBUG >= level
      end                                      # end
    EOT
  end

  private

    def thread_hash_level_key
      @thread_hash_level_key ||= :"ThreadSafeLogger##{object_id}@level"
    end

end

Should not

@thread_hash_level_key ||= :"ThreadSafeLogger##{object_id}@level"

be

@thread_hash_level_key ||= :"ThreadSafeLogger##{object_id}#{@level}"

?

Ok, my mistake, it wont work.