Class: Logging::Appenders::RollingFile

Inherits:
IO show all
Defined in:
lib/gems/logging-0.9.4/lib/logging/appenders/rolling_file.rb

Overview

An appender that writes to a file and ensures that the file size or age never exceeds some user specified level.

The goal of this class is to write log messages to a file. When the file age or size exceeds a given limit then the log file is closed, the name is changed to indicate it is an older log file, and a new log file is created.

The name of the log file is changed by inserting the age of the log file (as a single number) between the log file name and the extension. If the file has no extension then the number is appended to the filename. Here is a simple example:

/var/log/ruby.log   =>   /var/log/ruby.1.log

New log messages will be appended to a newly opened log file of the same name (/var/log/ruby.log in our example above). The age number for all older log files is incremented when the log file is rolled. The number of older log files to keep can be given, otherwise all the log files are kept.

The actual process of rolling all the log file names can be expensive if there are many, many older log files to process.

Instance Attribute Summary

Attributes inherited from Logging::Appender

#layout, #level, #name

Instance Method Summary collapse

Methods inherited from IO

#close, #flush

Methods inherited from Logging::Appender

#<<, [], []=, #append, #close, #closed?, #flush, #inspect, remove, stderr, stdout

Constructor Details

#initialize(name, opts = {}) ⇒ RollingFile

call-seq:

RollingFile.new( name, opts )

Creates a new Rolling File Appender. The name is the unique Appender name used to retrieve this appender from the Appender hash. The only required option is the filename to use for creating log files.

[:filename]  The base filename to use when constructing new log
             filenames.

The following options are optional:

[:layout]    The Layout that will be used by this appender. The Basic
             layout will be used if none is given.
[:truncate]  When set to true any existing log files will be rolled
             immediately and a new, empty log file will be created.
[:size]      The maximum allowed size (in bytes) of a log file before
             it is rolled.
[:age]       The maximum age (in seconds) of a log file before it is
             rolled. The age can also be given as 'daily', 'weekly',
             or 'monthly'.
[:keep]      The number of rolled log files to keep.
[:safe]      When set to true, extra checks are made to ensure that
             only once process can roll the log files; this option
             should only be used when multiple processes will be
             logging to the same log file (does not work on Windows)

Raises:

  • (ArgumentError) 


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# File 'lib/gems/logging-0.9.4/lib/logging/appenders/rolling_file.rb', line 59

def initialize( name, opts = {} )
  # raise an error if a filename was not given
  @fn = opts.getopt(:filename, name)
  raise ArgumentError, 'no filename was given' if @fn.nil?
  ::Logging::Appenders::File.assert_valid_logfile(@fn)

  # grab the information we need to properly roll files
  ext = ::File.extname(@fn)
  bn = ::File.join(::File.dirname(@fn), ::File.basename(@fn, ext))
  @rgxp = %r/\.(\d+)#{Regexp.escape(ext)}\z/
  @glob = "#{bn}.*#{ext}"
  @logname_fmt = "#{bn}.%d#{ext}"

  # grab our options
  @keep = opts.getopt(:keep, :as => Integer)
  @size = opts.getopt(:size, :as => Integer)

  @lockfile = if opts.getopt(:safe, false) and !::Logging::WIN32
    ::Lockfile.new(
        @fn + '.lck',
        :retries => 1,
        :timeout => 2
    )
  end

  code = 'def sufficiently_aged?() false end'
  @age_fn = @fn + '.age'

  case @age = opts.getopt(:age)
  when 'daily'
    FileUtils.touch(@age_fn) unless test(?f, @age_fn)
    code = <<-CODE
    def sufficiently_aged?
      now = Time.now
      start = ::File.mtime(@age_fn)
      if (now.day != start.day) or (now - start) > 86400
        return true
      end
      false
    end
    CODE
  when 'weekly'
    FileUtils.touch(@age_fn) unless test(?f, @age_fn)
    code = <<-CODE
    def sufficiently_aged?
      if (Time.now - ::File.mtime(@age_fn)) > 604800
        return true
      end
      false
    end
    CODE
  when 'monthly'
    FileUtils.touch(@age_fn) unless test(?f, @age_fn)
    code = <<-CODE
    def sufficiently_aged?
      now = Time.now
      start = ::File.mtime(@age_fn)
      if (now.month != start.month) or (now - start) > 2678400
        return true
      end
      false
    end
    CODE
  when Integer, String
    @age = Integer(@age)
    FileUtils.touch(@age_fn) unless test(?f, @age_fn)
    code = <<-CODE
    def sufficiently_aged?
      if (Time.now - ::File.mtime(@age_fn)) > @age
        return true
      end
      false
    end
    CODE
  end
  meta = class << self; self end
  meta.class_eval code, __FILE__, __LINE__

  # if the truncate flag was set to true, then roll 
  roll_now = opts.getopt(:truncate, false)
  roll_files if roll_now

  super(name, open_logfile, opts)
end