log_line_durations.rb

#!/bin/ruby

require 'date'

THRESHOLD = ARGV[0].to_i || 10 # seconds
prev_line = ''
prev_dtm = nil
prev_line_printed = false

def seconds_between(dtm1, dtm2)
  seconds_in_a_day = 24 * 60 * 60
  ((dtm2 - dtm1) * seconds_in_a_day).round # dtm - dtm is a Rational of how many days
end

def humanize(seconds)
  hours = seconds / (60*60)
  seconds -= (hours * 60*60)
  minutes = seconds / 60
  seconds -= (minutes * 60)
  '%02d:%02d:%02d' % [hours,minutes,seconds]
end

STDIN.each_line do |line|
  timestamp_str = line.scan(/^\d{4}-\d{2}-\d{2} \d{2}:\d{2}:\d{2}/)

  next if timestamp_str.nil?

  dtm = DateTime.parse(timestamp_str.first) || timestamp_str.empty?

  unless prev_dtm.nil?
    secs = seconds_between(prev_dtm, dtm)
    if secs > THRESHOLD
      unless prev_line_printed
        puts
        puts " "*9 + prev_line
      end
      
      puts humanize(secs) + " " + line
      prev_line_printed = true
    else
      prev_line_printed = false
    end

  end

  prev_dtm = dtm
  prev_line = line
end

         2014-03-31 07:34:38,845 INFO  [TransactionReaderCommand] Read 169359 transactions, 169359 transactions skipped.
01:15:14 2014-03-31 08:49:52,889 INFO  [TransactionReaderCommand] reading transactions from file input