vendor/rails/activesupport/lib/active_support/buffered_logger.rb

   1 module ActiveSupport
   2   # Inspired by the buffered logger idea by Ezra
   3   class BufferedLogger
   4     module Severity
   5       DEBUG   = 0
   6       INFO    = 1
   7       WARN    = 2
   8       ERROR   = 3
   9       FATAL   = 4
  10       UNKNOWN = 5
  11     end
  12     include Severity
  13
  14     MAX_BUFFER_SIZE = 1000
  15
  16     # Set to false to disable the silencer
  17     cattr_accessor :silencer
  18     self.silencer = true
  19
  20     # Silences the logger for the duration of the block.
  21     def silence(temporary_level = ERROR)
  22       if silencer
  23         begin
  24           old_logger_level, self.level = level, temporary_level
  25           yield self
  26         ensure
  27           self.level = old_logger_level
  28         end
  29       else
  30         yield self
  31       end
  32     end
  33
  34     attr_accessor :level
  35     attr_reader :auto_flushing
  36
  37     def initialize(log, level = DEBUG)
  38       @level         = level
  39       @buffer        = {}
  40       @auto_flushing = 1
  41       @guard = Mutex.new
  42
  43       if log.respond_to?(:write)
  44         @log = log
  45       elsif File.exist?(log)
  46         @log = open(log, (File::WRONLY | File::APPEND))
  47         @log.sync = true
  48       else
  49         FileUtils.mkdir_p(File.dirname(log))
  50         @log = open(log, (File::WRONLY | File::APPEND | File::CREAT))
  51         @log.sync = true
  52         @log.write("# Logfile created on %s" % [Time.now.to_s])
  53       end
  54     end
  55
  56     def add(severity, message = nil, progname = nil, &block)
  57       return if @level > severity
  58       message = (message || (block && block.call) || progname).to_s
  59       # If a newline is necessary then create a new message ending with a newline.
  60       # Ensures that the original message is not mutated.
  61       message = "#{message}\n" unless message[-1] == ?\n
  62       buffer << message
  63       auto_flush
  64       message
  65     end
  66
  67     for severity in Severity.constants
  68       class_eval <<-EOT, __FILE__, __LINE__
  69         def #{severity.downcase}(message = nil, progname = nil, &block)
  70           add(#{severity}, message, progname, &block)
  71         end
  72
  73         def #{severity.downcase}?
  74           #{severity} >= @level
  75         end
  76       EOT
  77     end
  78
  79     # Set the auto-flush period. Set to true to flush after every log message,
  80     # to an integer to flush every N messages, or to false, nil, or zero to
  81     # never auto-flush. If you turn auto-flushing off, be sure to regularly
  82     # flush the log yourself -- it will eat up memory until you do.
  83     def auto_flushing=(period)
  84       @auto_flushing =
  85         case period
  86         when true;                1
  87         when false, nil, 0;       MAX_BUFFER_SIZE
  88         when Integer;             period
  89         else raise ArgumentError, "Unrecognized auto_flushing period: #{period.inspect}"
  90         end
  91     end
  92
  93     def flush
  94       @guard.synchronize do
  95         unless buffer.empty?
  96           old_buffer = buffer
  97           clear_buffer
  98           @log.write(old_buffer.join)
  99         end
 100       end
 101     end
 102
 103     def close
 104       flush
 105       @log.close if @log.respond_to?(:close)
 106       @log = nil
 107     end
 108
 109     protected
 110       def auto_flush
 111         flush if buffer.size >= @auto_flushing
 112       end
 113
 114       def buffer
 115         @buffer[Thread.current] ||= []
 116       end
 117
 118       def clear_buffer
 119         @buffer.delete(Thread.current)
 120       end
 121   end
 122 end