stats.rb

require 'socket'
require 'rubygems'
require 'collectd/pkt'

class Stats
  def initialize name, instance, opts = {}
    @name, @instance = name, instance

    @sock = UDPSocket.new
    @sock.connect opts[:host] || '239.192.74.66',
                  opts[:port] || 25826

    @hostname = opts[:hostname] || `/bin/hostname -s`.strip
    @interval = opts[:interval] || 10

    @counters, @gauges, @counts = {}, {}, {}
  end

  def counter_set name, val
    flush_outbound
    @counters[name] = val
  end

  def counter_inc name, val
    flush_outbound
    @counters[name] = @counters.has_key?(name) ? @counters[name] + val : val
  end

  def gauge_set name, val
    flush_outbound
    @gauges[name] = @gauges.has_key?(name) ? @gauges[name] + val : val
    @counts[name] = @counts.has_key?(name) ? @counts[name] + 1 : 1.0
  end

  private

  include Collectd

  def flush_outbound
    @time ||= Time.now

    if @time < Time.now - @interval
      @packet = [
        Packet::Host.new(@hostname),
        Packet::Time.new(@time.to_i),
        Packet::Interval.new(@interval),
        Packet::Plugin.new(@name),
        Packet::PluginInstance.new(@instance)
      ]

      @counters.each do |key, val|
        @packet << Packet::Type.new(:counter)
        @packet << Packet::TypeInstance.new(key)
        @packet << Packet::Values.new([ Packet::Values::Counter.new(val) ])
      end

      @gauges.each do |key, val|
        @packet << Packet::Type.new(:gauge)
        @packet << Packet::TypeInstance.new(key)
        @packet << Packet::Values.new([ Packet::Values::Gauge.new(val/@counts[key]) ])
      end
      @gauges = {}
      @counts = {}

      @sock.send @packet.join(''), 0

      @time = Time.now
    end
  end
end

if __FILE__ == $0
  s = Stats.new('ruby', 'test', :interval => 1)

  s.counter_set(:seconds, 5)
  while sleep(0.1)
    s.counter_inc(:seconds, 1)
    s.gauge_set(:sinwave, Math.sin(Time.now.to_f/60) * 100)
  end
end