Rails 3 logs with severity and PIDs

better_logger.rb

# You must require this file in application.rb, above the Application
# definition, for this to work. For example:
#
#   # PIDs prepended to logs
#   if Rails.env.production?
#     require File.expand_path('../../lib/pid_logger', __FILE__)
#   end
#
#   module MyApp
#     class Application < Rails::Application

require 'active_support/buffered_logger'

class PidLogger < ActiveSupport::BufferedLogger

  SEVERITIES = Severity.constants.sort_by{|c| Severity.const_get(c) }

  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
    message.gsub!(/^(.+)/, "[#{$$}] #{SEVERITIES[severity]} \\1")
    buffer << message
    auto_flush
    message
  end

  class Railtie < ::Rails::Railtie
    initializer "swap in PidLogger" do
      path = Rails.application.config.paths.log.first
      level = Rails.logger.level
      Rails.logger = PidLogger.new(path, level)
      ActiveSupport::Dependencies.logger = Rails.logger
      Rails.cache.logger = Rails.logger
      ActiveSupport.on_load(:active_record) do
        ActiveRecord::Base.logger = Rails.logger
      end
      ActiveSupport.on_load(:action_controller) do
        ActionController::Base.logger = Rails.logger
      end
      ActiveSupport.on_load(:action_mailer) do
        ActionMailer::Base.logger = Rails.logger
      end
    end
  end

end