Class: Munchies::Logfile

Inherits:
Object
  • Object
show all
Includes:
Enumerable
Defined in:
lib/munchies.rb

Constant Summary collapse

TIME_REGEXP =

Matches timestamps in logfile

/^\d{4}-\d{2}-\d{2}T\d{2}\:\d{2}\:\d{2}\b/

Instance Method Summary collapse

Constructor Details

#initialize(path, starting_at = Time.now) ⇒ Logfile

Returns a new instance of Logfile.

Raises:

  • (ArgumentError) 


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# File 'lib/munchies.rb', line 11

def initialize path, starting_at = Time.now
  raise ArgumentError unless File.exists?( path )

  @log            = File.open( path )
  @ending_at      = starting_at
  @starting_at    = (@ending_at - 300)
end

Instance Method Details

#backwards ⇒ Object 



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# File 'lib/munchies.rb', line 19

def backwards

  filesize      = @log.stat.size
  buffer_size   = 128000
  offset        = buffer_size

  # Seek to the end of the file
  @log.seek(0, File::SEEK_END)

  timestamp     = @starting_at.strftime("%FT%T")

  while @log.tell > 0
    @log.seek(-offset, File::SEEK_END)

    buffer = @log.read( buffer_size )

    # Look at the first two lines of the buffer and check if we are close
    # to the desired timestamp. First line may be incomplete.
    #
    buffer_line = buffer.split("\n")[1]
    if (t = buffer_line.match(TIME_REGEXP)) && (t[0] < timestamp)

      (1..300).each do |i|

        if index = buffer.index( timestamp )
          # Calculate byte offest and seek to this position
          position = (@log.tell - buffer_size + index)
          @log.seek( position, File::SEEK_SET )
          return
        end

        # If the first timestamp doesn't match count up seconds until it does
        timestamp = (@starting_at + i).strftime("%FT%T")
      end
    end

    offset += buffer_size

    return if offset > filesize
  end

end

#each(&block) ⇒ Object 



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# File 'lib/munchies.rb', line 62

def each &block
  backwards

  @log.each_line do |line|
    yield line
  end
end