Combine RSS memory usage and Apache 2 /server-status for heatmap with Datadog.

apache-memory-pid-stats.rb

require 'rubygems'
require 'nokogiri'
require 'open-uri'
require 'pp'
require 'statsd'

statsd = Statsd.new

def get_memory_usage
  memory_usage = {}
  ps = `ps -C apache2 -o pid,rss --no-header`
  memory = ps.split("\n")
  memory = memory.collect{|mem| mem.strip}
  memory.each do |mem|
   usage = mem.split(" ")
   memory_usage[usage[0]] = usage[1]
  end
  memory_usage
end


while true do

  memory = get_memory_usage

  puts "#{memory.count} processes Memory Usage: #{memory.inspect}"

  doc = Nokogiri::HTML(open("http://127.0.0.1/server-status"))

  rows = doc.xpath("//tr")

  running = 1

  rows.each do |row|
    if row.children[0].name == 'td'
      array = row.children.to_a

      if array[1].to_s != "<td>-</td>\n"
        pid = array[1].to_s.scan(/[0-9]*/)
        site = array[11].to_s.scan(/<td nowrap>(.*)<\/td>/)
        puts "We have a running process number #{running}"
        puts "Process: #{pid}"
        puts "Memory: " + memory["#{pid}"] unless memory["#{pid}"].nil?
        puts "Site:    '#{site}' #{site.class}"
        running += 1
        if site.to_s =~ /\*\.bam/
          puts "Not sending stats for bam - not useful"
        elsif site.to_s =~ /\?/
          puts "NOT sending stats for unknown site."
        else
          statsd.histogram('apache.rss_memory_tagged', memory["#{pid}"], :tags => ["site:#{site}"])
          puts "Sent stats for #{site}"
        end
        puts "\n\n"
      end
    end
  end

  sleep(5)

end

datadog.json

{
  "viz": "heatmap",
  "requests": [
    {
      "q": "avg:apache.rss_memory_tagged.max{host:bam} by {site}",
      "type": "area"
    }
  ],
  "events": []
}