require 'thread' require 'active_support/core_ext/class/attribute_accessors' module ActiveSupport # Inspired by the buffered logger idea by Ezra class BufferedLogger module Severity DEBUG = 0 INFO = 1 WARN = 2 ERROR = 3 FATAL = 4 UNKNOWN = 5 end include Severity MAX_BUFFER_SIZE = 1000 ## # :singleton-method: # Set to false to disable the silencer cattr_accessor :silencer self.silencer = true # Silences the logger for the duration of the block. def silence(temporary_level = ERROR) if silencer begin old_logger_level, self.level = level, temporary_level yield self ensure self.level = old_logger_level end else yield self end end attr_accessor :level attr_reader :auto_flushing def initialize(log, level = DEBUG) @level = level @buffer = {} @auto_flushing = 1 @guard = Mutex.new if log.respond_to?(:write) @log = log elsif File.exist?(log) @log = open(log, (File::WRONLY | File::APPEND)) @log.sync = true else FileUtils.mkdir_p(File.dirname(log)) @log = open(log, (File::WRONLY | File::APPEND | File::CREAT)) @log.sync = true end end 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 # Dynamically add methods such as: # def info # def warn # def debug for severity in Severity.constants class_eval <<-EOT, __FILE__, __LINE__ + 1 def #{severity.downcase}(message = nil, progname = nil, &block) # def debug(message = nil, progname = nil, &block) add(#{severity}, message, progname, &block) # add(DEBUG, message, progname, &block) end # end def #{severity.downcase}? # def debug? #{severity} >= @level # DEBUG >= @level end # end EOT end # Set the auto-flush period. Set to true to flush after every log message, # to an integer to flush every N messages, or to false, nil, or zero to # never auto-flush. If you turn auto-flushing off, be sure to regularly # flush the log yourself -- it will eat up memory until you do. def auto_flushing=(period) @auto_flushing = case period when true; 1 when false, nil, 0; MAX_BUFFER_SIZE when Integer; period else raise ArgumentError, "Unrecognized auto_flushing period: #{period.inspect}" end end def flush @guard.synchronize do unless buffer.empty? old_buffer = buffer all_content = StringIO.new old_buffer.each do |content| all_content << content end @log.write(all_content.string) end # Important to do this even if buffer was empty or else @buffer will # accumulate empty arrays for each request where nothing was logged. clear_buffer end end def close flush @log.close if @log.respond_to?(:close) @log = nil end protected def auto_flush flush if buffer.size >= @auto_flushing end def buffer @buffer[Thread.current] ||= [] end def clear_buffer @buffer.delete(Thread.current) end end end