Passenger - Statsd

passenger-statsd.rb

#! /usr/bin/ruby
require 'socket'

statsd_host      = ""
statsd_port      = "8125"
namespace_prefix = "statsd-ruby"
mode             = "statsd"

ARGV.each do |arg|
  name, value = arg.split '='
  case name
    when 'host'       then statsd_host      = value
    when 'namespace'  then namespace_prefix = value
    when 'port'       then statsd_port      = value
    when 'mode'       then mode             = value
    else
      exit("#{name} is not a valid parameter")
  end
end

namespace = "#{namespace_prefix}.passenger.#{Socket.gethostname}"

loop do
  metrics = []
  `passenger-status`.each_line do |line|
    value = nil
    field = nil
    case line
      when /^Processes/
        field = "processes"
      when /^Requests in top-level queue/
        field = "queue"
    end
    value = line.split(':').pop.strip
    next unless value && field
    metrics << "#{namespace}.#{field}:#{value}|g"
  end

  # Average memory consumption of passenger processes
  line_count = 0
  mem_total = 0
  `passenger-memory-stats 2>/dev/null`.each_line do |line|
    case line
      when /RackApp/
        mem_total  += (line.split(' ')[3]).to_f
        line_count += 1
    end
  end
  if line_count > 0
    value = (mem_total / line_count).to_i
    metrics << "#{namespace}.avg_mem:#{value}|g"
    metrics << "#{namespace}.total_mem:#{mem_total}|g"
  end

  packet = metrics.join("\n")
  if mode == 'statsd'
    socket = UDPSocket.open.send(packet, 0, statsd_host, statsd_port)
  elsif mode == 'stdout'
    puts packet
  else
    puts "#{mode} is not a valid output mode. Valid modes are 'statsd' (default) and 'stdout'."
    exit
  end

  sleep(10)
end