gistfile1.txt

  def filter_repeated
    if @event['check']['name'] == 'keepalive'
      # Keepalives are a special case because they don't emit an interval.
      # They emit a heartbeat every 20 seconds per
      # http://sensuapp.org/docs/0.12/keepalives
      interval = 20
    else
      interval      = @event['check']['interval'].to_i || 0
    end
    alert_after   = @event['check']['alert_after'].to_i || 0
    realert_every = @event['check']['realert_every'].to_i || 1

    initial_failing_occurrences = interval > 0 ? (alert_after / interval) : 0
    number_of_failed_attempts = @event['occurrences'] - initial_failing_occurrences

    # Don't bother acting if we haven't hit the 
    # alert_after threshold
    if number_of_failed_attempts < 1
      bail "Not failing long enough, only #{number_of_failed_attempts} after " \
        "#{initial_failing_occurrences} initial failing occurrences"
    # If we have an interval, and this is a creation event, that means we are
    # an active check
    # Lets also filter based on the realert_every setting
    elsif interval > 0 and @event['action'] == 'create' 
      # Special case of exponential backoff
      if realert_every == -1
        # If our number of failed attempts is an exponent of 2
        if power_of_two?(number_of_failed_attempts)
          # Then This is our MOMENT!
          return nil
        else
          bail "not on a power of two: #{number_of_failed_attempts}"
        end
      elsif (number_of_failed_attempts - 1) % realert_every != 0
        # Now bail if we are not in the realert_every cycle
        bail "only handling every #{realert_every} occurrences, and we are at" \
          " #{number_of_failed_attempts}"
      end
    end
  end