crxn-flapping-detector/detector.rb

require 'faye/websocket'
require 'eventmachine'
require 'psych'

class FlappingDetector

  def initialize ws_addr, threshold = 10
    @ws_addr = ws_addr
    @flapping = {}
    @flapping.default = 0
    @threshold = threshold
  end

  def run
    EM.run do
      ws = Faye::WebSocket::Client.new(@ws_addr)

      register_open_handler ws
      register_message_handler ws
      register_close_handler ws
    end
  end

  private

  def check_for_flapping
    time_waited = Time.now - @start
    puts "Checking for flapping... #{time_waited} seconds since the connection was established."
    @flapping.each_pair do |prefix, count|
      if count > ((time_waited.to_i / 60) + 1) * @threshold
        puts "#{prefix} is flapping. I reveived #{count} updates for it."
      end
    end
  end

  def register_open_handler ws
    ws.on :open do
      puts 'Connection established.'
      @start = Time.now
      Thread.new do
        puts "Threshold is #{@threshold} updates per minute."
        loop do
          check_for_flapping
          puts 'Waiting...'
          sleep 1
        end
      end
    end
  end

  def register_message_handler ws
    ws.on :message do |event|
      data = Psych.safe_load event.data
      case data['table']
      when 'route'
        @flapping[data['data']['prefix']] += 1
      when 'neighbour'
        @flapping[data['data']['if']] += 1
      end
    end
  end

  def register_close_handler ws
    ws.on :close do |event|
      ws = nil
      puts "Connection closed. Code: #{event.code}; Reason: #{event.reason}"
    end
  end

end