JMeter log file extractor for GnuPlot

logfile_filter.rb

class LogfileFilter

  def initialize regex1, regex2, input_file_name, output_file_name
    @read_file = File.new input_file_name, "r"
    puts "Reading file #{input_file_name}"

    @write_file = File.new output_file_name, "w"
    puts "Writing to file #{output_file_name}"

    @reg_ex_1 = Regexp.new regex1
    @reg_ex_2 = Regexp.new regex2

    @reg_ex_ts = /ts="(\d+)"/
    @reg_ex_t = /t="(\d+)"/

    puts "First condition for filtering: #{@reg_ex_1.inspect}"
    puts "Second condition for filtering: #{@reg_ex_2.inspect}"
    puts "---"

  end


  def parse_file

    @write_file.puts "#Time ElapsedTime"

    matches = 0
    # ... process all lines in the file
    @read_file.each_line do |line|


      if (line.match @reg_ex_1) && (line.match @reg_ex_2)
        matches+=1
        # print line
        # puts line

        m = line.match(@reg_ex_ts)
        epoch_ms = m[1]
        epoch_s = epoch_ms[0...-3] # cut-off milliseconds
        time = Time.at (epoch_s.to_i)

        m = line.match(@reg_ex_t)
        elapsed = m[1]

        @write_file.puts "#{time.utc.strftime("%H:%M:%S")} #{elapsed}"


      end

    end

    puts "---"
    puts "#{@read_file.lineno} lines read"
    puts "#{matches} matches found"
    @read_file.close
  end

end


# commandline

# get file name from command line
if ARGV.size < 4
  puts "Error: Arguments missing"
  puts "Usage: logfile_filter.rb regex filename"
  puts "regex: Regular expression which is used for filtering lines"
  puts "filename: Name of the file to be filtered"
  exit(1)
end

write_file = ARGV.pop
file_name = ARGV.pop
regex2 = ARGV.pop
regex1 = ARGV.pop
analyzer = LogfileFilter.new regex1, regex2, file_name, write_file
analyzer.parse_file

This file belongs to JMeter log file extractor for GnuPlot: http://www.datazoo.de/articles/158/performance-testing-analyzing-jmeter-results

Example reading the log file called jmeter_results.log , writing to file the_start.dat , using two regular expressions lb=\"the start\" and s=\"true\" as conditions to extract elapsed time and timestamp from the line of the logfile:
logfile_filter.rb "lb="the start"" s="true" jmeter_results.log the_start.dat

Regular expressions with spaces inside should be surrounded by double-quotes, see "lb=\"the start\""