Class: Logging::Appenders::RollingFile::Roller

Inherits:
Object
  • Object
show all
Defined in:
lib/logging/appenders/rolling_file.rb

Overview

Not intended for general consumption, but the Roller class is used internally by the RollingFile appender to roll dem log files according to the user's desires.

Constant Summary collapse

RGXP =

The magic regex for finding user-defined roller patterns.

%r/{{(([^%]+)?.*?)}}/

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(filename, age: nil, size: nil, roll_by: nil, keep: nil) ⇒ Roller

Create a new roller. See the RollingFile#initialize documentation for the list of options.

filename - the name of the file to roll age - the age of the file at which it should be rolled size - the size of the file in bytes at which it should be rolled roll_by - roll either by 'number' or 'date' keep - the number of log files to keep when rolling

Raises:

  • (ArgumentError)

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# File 'lib/logging/appenders/rolling_file.rb', line 290

def initialize( filename, age: nil, size: nil, roll_by: nil, keep: nil )
  # raise an error if a filename was not given
  @fn = filename
  raise ArgumentError, 'no filename was given' if @fn.nil?

  if (m = RGXP.match @fn)
    @roll_by = ("#{m[2]}%d" == m[1]) ? :number : :date
  else
    @roll_by =
        case roll_by
        when 'number'; :number
        when 'date'; :date
        else
          (age && !size) ? :date : :number
        end

    ext = ::File.extname(@fn)
    bn  = ::File.join(::File.dirname(@fn), ::File.basename(@fn, ext))

    @fn = if :date == @roll_by && %w[daily weekly monthly].include?(age)
            "#{bn}{{.%Y%m%d}}#{ext}"
          elsif :date == @roll_by
            "#{bn}{{.%Y%m%d-%H%M%S}}#{ext}"
          else
            "#{bn}{{.%d}}#{ext}"
          end
  end

  @fn = ::File.expand_path(@fn)
  ::Logging::Appenders::File.assert_valid_logfile(filename)

  @roll = false
  @keep = keep.nil? ? nil : Integer(keep)
end

Instance Attribute Details

#keepObject (readonly)

Returns the value of attribute keep.


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# File 'lib/logging/appenders/rolling_file.rb', line 325

def keep
  @keep
end

#rollObject

Returns the value of attribute roll.


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# File 'lib/logging/appenders/rolling_file.rb', line 326

def roll
  @roll
end

#roll_byObject (readonly)

Returns the value of attribute roll_by.


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# File 'lib/logging/appenders/rolling_file.rb', line 325

def roll_by
  @roll_by
end

Instance Method Details

#copy_fileObject

Returns the file name to use as the temporary copy location. We are using copy-and-truncate semantics for rolling files so that the IO file descriptor remains valid during rolling.


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# File 'lib/logging/appenders/rolling_file.rb', line 338

def copy_file
  return @copy_file if defined? @copy_file
  @copy_file = filename + '._copy_'
  @copy_file.freeze
end

#filenameObject

Returns the regular log file name without any roller text.


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# File 'lib/logging/appenders/rolling_file.rb', line 329

def filename
  return @filename if defined? @filename
  @filename = (@fn =~ RGXP ?  @fn.sub(RGXP, '') : @fn.dup)
  @filename.freeze
end

#formatObject

Returns the format String used to generate rolled file names. Depending upon the `roll_by` type (:date or :number), this String will be processed by `sprintf` or `Time#strftime`.


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# File 'lib/logging/appenders/rolling_file.rb', line 356

def format
  return @format if defined? @format
  m = RGXP.match @fn
  @format = @fn.sub(RGXP, m[1])
  @format.freeze
end

#globObject

Returns the glob pattern used to find rolled log files. We use this list for pruning older log files and doing the numbered rolling.


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# File 'lib/logging/appenders/rolling_file.rb', line 346

def glob
  return @glob if defined? @glob
  m = RGXP.match @fn
  @glob = @fn.sub(RGXP, (m[2] ? "#{m[2]}*" : '*'))
  @glob.freeze
end

#roll_by_date(files) ⇒ Object

Roll the list of log files optionally removing older files. The “older files” are determined by the mtime of the log files. So touching log files or otherwise messing with them will screw this up.

files - The Array of filename Strings

Returns nil


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# File 'lib/logging/appenders/rolling_file.rb', line 418

def roll_by_date( files )
  length = files.length

  if keep && length >= keep
    files = files.sort do |a,b|
              a = ::File.mtime(a)
              b = ::File.mtime(b)
              b <=> a
            end
    files.last(length-keep+1).each { |fn| ::File.delete fn }
  end

  # rename the copied log file
  ::File.rename(copy_file, Time.now.strftime(format))
end

#roll_by_number(files) ⇒ Object

Roll the list of log files optionally removing older files. The “older files” are determined by extracting the number from the log file name and order by the number.

files - The Array of filename Strings

Returns nil


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# File 'lib/logging/appenders/rolling_file.rb', line 387

def roll_by_number( files )
  @number_rgxp ||= Regexp.new(@fn.sub(RGXP, '\2(\d+)'))

  # sort the files in reverse order based on their count number
  files = files.sort do |a,b|
            a = Integer(@number_rgxp.match(a)[1])
            b = Integer(@number_rgxp.match(b)[1])
            b <=> a
          end

  # for each file, roll its count number one higher
  files.each do |fn|
    cnt = Integer(@number_rgxp.match(fn)[1])
    if keep && cnt >= keep
      ::File.delete fn
      next
    end
    ::File.rename fn, sprintf(format, cnt+1)
  end

  # finally rename the copied log file
  ::File.rename(copy_file, sprintf(format, 1))
end

#roll_filesObject

Roll the log files. This method will collect the list of rolled files and then pass that list to either `roll_by_number` or `roll_by_date` to perform the actual rolling.

Returns nil


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# File 'lib/logging/appenders/rolling_file.rb', line 368

def roll_files
  return unless roll && ::File.exist?(copy_file)

  files = Dir.glob(glob)
  files.delete copy_file

  self.send "roll_by_#{roll_by}", files
  nil
ensure
  self.roll = false
end