a really threadsafe! (buffered) logger

thread_safe_logger.rb

require 'thread'

# ActiveSupport::BufferedLogger is not completely thread-safe !
# well it is if You disable the silencer :
#
#   ActiveSupport::BufferedLogger.silencer = false
#
# if You'd like to use `logger.silence {  }` it might permanently
# change the level if 2 threads perform silencing at the same time
class ThreadSafeLogger < ActiveSupport::BufferedLogger

  def initialize(log, level = DEBUG)
    super
    @level = { nil => level }
  end
  
  def silence(temporary_level = ERROR)
    if silencer
      begin
        @level[Thread.current] = temporary_level
        yield self
      ensure
        @level.delete Thread.current
      end
    else
      yield self
    end
  end

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

  def level=(level)
    @level[nil] = 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
    # If a newline is necessary then create a new message ending with a newline.
    # Ensures that the original message is not mutated.
    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

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.