rmtr.rb

#!/usr/bin/env ruby

# Collects trace stats using mtr. Accepts the following environment variables
# and delegates all real arguments to the underlying call to the mtr program.
#
# VERBOSE=true REPORT_DIR=/path/to/report ENDPOINTS=foo.com,bar.com THRESHOLD=10.0 ./rmtr.rb foo.com -r -c 1000

require 'fileutils'

THRESHOLD  = ENV['THRESHOLD' ].to_i || 10
ENDPOINTS  = ENV['ENDPOINTS' ].split(',')
REPORT_DIR = ENV['REPORT_DIR'] || File.expand_path('../rmtr-report', __FILE__)
VERBOSE    = ENV['VERBOSE'   ] || false

FileUtils.mkdir_p(REPORT_DIR)

while true do
  result = %x[mtr #{ARGV.join(' ')}]
  if VERBOSE
    puts '-'*80
    puts result
    puts '-'*80
  end
  packet_loss = (ENDPOINTS.any? { |endpoint| result =~ /#{endpoint}\s*(\d*.\d*)%/ } ? $1.to_f : 100.0)
  if packet_loss >= THRESHOLD
    puts "WARNING: #{packet_loss}% packet loss"
    file = "#{REPORT_DIR}/#{Time.now.strftime('%Y_%m_%d__%H-%M-%S')}__#{packet_loss}.txt"
    File.open(file, 'w') do |f|
      f.puts result
    end
  end
end