#!/usr/bin/env ruby
############  connectdurations -- brent@mbari.org  #####################
#    Copyright (C) 2008 MBARI
#    MBARI Proprietary Information. All rights reserved.
#
#   Exctract pppd connection durations from /var/log/messages
#
########################################################################

require 'getoptlong'
require 'timehash'

opts = GetoptLong.new(
  ["--help", "-h",  GetoptLong::NO_ARGUMENT],
  ["--minup", "-u", GetoptLong::REQUIRED_ARGUMENT],
  ["--mindown", "-d", GetoptLong::REQUIRED_ARGUMENT],
  ["--year", '-y', GetoptLong::REQUIRED_ARGUMENT],
  ["--gmt", '-g',  GetoptLong::NO_ARGUMENT],
  ["--UTC", '-U',  GetoptLong::NO_ARGUMENT]
)

progName = File.basename $0
minUp = minDown = 0
baseYear = Time.now.year
tz = ''
tzMethod = :localtime
form = '%.2f'

logDate = '([[:alpha:]]+\s+\d+\s+\d+:\d+:\d+)\s+'
logProcess = '(\w+)(\[(\d+)\])?'
logLine = Regexp.new(logDate+logProcess+':\s+(.*)')
# [1] == date
# [2] == process name
# [4] == PID  (optional)
# [-1] == message text

opts.each do |opt, arg|
  case opt
    when '--minup'
      minUp = Float(arg)
    when '--mindown'
      minDown = Float(arg)
    when '--year'
      baseYear = Integer(arg)
    when '--gmt'
      tz = ' UTC'
    when '--UTC'
      tzMethod=:utc
    else
      $stderr.puts "\
Extract ppp connection durations from syslog -- brent@mbari.org  6/12/08
Options:
  --help              #displays this text
  --minup=seconds     #don't report connections shorter than this
  --mindown=seconds   #don't report connection interruptions shorter than this
  --year=#{baseYear}    #assume log entries begin in specified year
  --gmt               #assume log times are UTC (default is local time)
  --UTC               #convert times to UTC

Expects to read a syslog (i.e. /var/log/messages) via STDIN

Examples:
  #{progName} < /var/log/messages
"
    exit
  end
end

downSince = upSince = nil
Time.last = Time("0:0:0.0 1/1/#{baseYear}"<<tz)

def parseTime string
  result = ParseDate.instant string
  Time.last = result - 1e-4  #don't interpret repeated times as change in year
  result
end

while line=gets
  field = logLine.match line
  if field
    if field[2] == 'pppd'
      case field[-1]
        when /.*terminated.*/
          downSince ||= parseTime(field[1]<<tz).send(tzMethod)
          if upSince
            upMins = (downSince - upSince)/60
            puts "#{upSince}    up #{form % upMins} minutes" if upMins >= minUp
            upSince = nil
          end
        when /local.*address.*/
          upSince ||= parseTime(field[1]<<tz).send(tzMethod)
          if downSince
            downMins = (upSince - downSince)/60
            puts "#{downSince}  down #{form%downMins} minutes" if downMins >= minDown
            downSince = nil
          end
      end
    end
  else
    STDERR.puts "parse error on line #{STDIN.lineno}"
  end
end