rails line logger

line_logger.rb

#inspired (a lot) by http://blog.gugl.org/archives/47

# Note, to achieve this I should only have to define a formatter.
# why BufferedLogger instead of Logger with a buffered IO?
# I suspect there is a reason for BufferedLogger so I'll keep it
class LineLogger < ActiveSupport::BufferedLogger

  SEVERITIES = Severity.constants.inject([]) {|arr,c| arr[Severity.const_get(c)] = c; arr}

  attr_writer :formatter

  def initialize(log, level = DEBUG, formatter = nil)
    super(log, level)
    @formatter = formatter || Logger::Formatter.new
  end

  def add(severity, message = nil, progname = nil, & block)
    return if @level > severity
    message = @formatter.call(SEVERITIES[severity], Time.now, progname, message)
    buffer << message
    auto_flush
    message
  end

end

production.rb

  begin
    config.logger = LineLogger.new(paths.log.paths[0])
    config.logger.level = LineLogger::WARN
    # This is what Rails does by default in production mode when using the default logger
    config.logger.auto_flushing = false
  rescue StandardError
    #this is also what rails does in case of failure, see initializer.rb
    config.logger = ActiveSupport::BufferedLogger.new(STDERR)
    config.logger.level = ActiveSupport::BufferedLogger::WARN
    config.logger.warn(
            "Rails Error: Unable to access log file. Please ensure that #{paths.log.paths[0]} exists and is chmod 0666. " +
                    "The log level has been raised to WARN and the output directed to STDERR until the problem is fixed."
    )
  end