Create heatmap json for Apache Ambari

ambari_heatmap_json.rb

#!/usr/bin/env ruby

require 'optparse'

class OptParse

  # Return a dictionary describing the options.
  #
  def self.parse(args)

    # The options specified on the command line will be collected in *options*.
    # We set default values here.
    options = {}
    options[:hosts] = 10
    options[:racks] = 3

    opt_parser = OptionParser.new do |opts|
      opts.banner = "Usage: example.rb [options]"

      opts.separator ""
      opts.separator "Specific options:"

      opts.on("-h N", OptionParser::DecimalInteger, "Hosts") do |n|
        options[:hosts] = n
      end

      opts.on("-r R", OptionParser::DecimalInteger, "Racks") do |n|
        options[:racks] = n
      end

    end

    opt_parser.parse!(args)
    options
  end  # parse()

end  # class OptParse



class HostsHeatmap

  # Return a hosts document
  #
  def self.generate(h, r)

    oses = ['rhel5', 'rhel6', 'centos5', 'centos6', 'suse11']
    metrics = {
      :cpu => 8.0,
      :disk => 242.884,
      :memory => 8013824
    } 
    comps = ['APP_TIMELINE_SERVER', 'DATANODE', 'GANGLIA_MONITOR', 'GANGLIA_SERVER','HDFS_CLIENT','HISTORYSERVER','MAPREDUCE2_CLIENT','NAGIOS_SERVER','NAMENODE','NODEMANAGER','RESOURCEMANAGER','SECONDARY_NAMENODE','TEZ_CLIENT','YARN_CLIENT','ZOOKEEPER_CLIENT','ZOOKEEPER_SERVER'] 

    header = '{"href":"localhost", "items": ['
    body = ''
    footer = ']}'

    host_template = %|
      {
      "Hosts":{
        "host_name":"%{rack}-%{host}",
        "ip":"127.0.1.%{host}",
        "os_type":"%{os}",
        "public_host_name":"%{rack}-%{host}.org",
        "rack_info":"/%{rack}"
      },
      "metrics":{
        "cpu":{
          "cpu_system":%{cpu_system},
          "cpu_user":%{cpu_user}
        },
        "disk":{
          "disk_free":%{disk_free},
          "disk_total":%{disk_total}
        },
        "memory":{
          "mem_free":%{memory_free},
          "mem_total":%{memory_total}
        }
      },
      "host_components":[
        %{host_components}
       ]
    },|

    component_template = %|{"HostRoles":{"component_name":"%{component}"}},|

    ### Generate rack_ids
    racks = r.times.map{ (0...8).map { ('a'..'z').to_a[rand(26)] }.join }
    
    ### Generate hosts
    (1..h).each do |n|
      host = n.to_s
      rack = racks.sample
      os = oses.sample
      
      cpu_system = rand(metrics[:cpu])
      cpu_user = rand(metrics[:cpu])

      disk_total = rand(metrics[:disk])
      disk_free = rand(disk_total)

      memory_total = rand(metrics[:memory])
      memory_free = rand(memory_total)

      host_components = ''
      components = comps.sample(rand(comps.length))
      components.each do |component|
        host_components << component_template % { :component => component }
      end
      ### Remove last comma
      host_components = host_components[0...-1]

      ### Fill the document
      body << host_template % { 
        :host => host, 
        :rack => rack, 
        :os => os, 
        :cpu_system => cpu_system,
        :cpu_user => cpu_user,
        :disk_free => disk_free,
        :disk_total => disk_total,
        :memory_free => memory_free,
        :memory_total => memory_total,
        :host_components => host_components
      }
    end
    
    ### Remove last comma
    body = body[0...-1]
    ### Get full document
    json = header << body << footer
    json

  end  # generate()
end  # class HostsHeatmap


options = OptParse.parse(ARGV)
print HostsHeatmap.generate(options[:hosts], options[:racks])