Summarize the hardware resources for a set of chef nodes

nodes_stats.rb

# hostname patters to search
patterns=["a-search*", "b-search*"]

TERA_SIZE = 1073741824.0*1024
GIGA_SIZE = 1073741824.0
MEGA_SIZE = 1048576.0
KILO_SIZE = 1024.0

# Return the file size with a readable style.
def human_size(size, precision=3)
  if size == 1
    "1 Byte"
  elsif size < KILO_SIZE
    "%d Bytes" % size
  elsif size < MEGA_SIZE
    "%.#{precision}f KB" % (size / KILO_SIZE)
  elsif size < GIGA_SIZE
    "%.#{precision}f MB" % (size / MEGA_SIZE)
  elsif size < TERA_SIZE
    "%.#{precision}f GB" % (size / GIGA_SIZE)
  else
    "%.#{precision}f TB" % (size / TERA_SIZE)
  end
end

def human_freq(mhz, precision=3)
  if mhz < 10**3
    "%d Mhz" % mhz
  elsif mhz < 10**6
    "%.#{precision}f GHz" % (mhz / 10**3.to_f)
  elsif mhz < 10**9
    "%.#{precision}f THz" % (mhz / 10**6.to_f)
  elsif mhz < 10**12
    "%.#{precision}f PHz" % (mhz / 10**9.to_f)
  else
    "#{mhz} MHz"
  end
end



cpus = 0
memory = 0
cpu_freq = 0

patterns.each { |pattern|
  nodes.find(:bootstrap_hostname => pattern).each { |node|
    if node.has_key?('cpu') then
      cpus += node.cpu.total.to_i
      if node['cpu'].has_key?('0')
        cpu_freq+=node['cpu']['0']['mhz'].to_i*node.cpu.total.to_i
      else
        cpu_freq+=node['cpu']['mhz'].to_i*node.cpu.total.to_i
      end
      if node.memory.total =~ /kB/
        memory+=node.memory.total.gsub("kB","").to_i*1024
      else
        memory+=node.memory.total.to_i
      end
    end
  }
}

puts "Search total CPUs : #{cpus}"
puts "Search CPU frequency : #{human_freq(cpu_freq)}"
puts "Search total memory : #{human_size(memory)}"

cpus=0
memory=0
cpu_freq = 0
hosts = 0

nodes.list.each { |node|
  begin
    if node.has_key?('cpu') then
      hosts+=1
      cpus += node.cpu.total.to_i
      if node['cpu'].has_key?('0')
        cpu_freq+=node['cpu']['0']['mhz'].to_i*node.cpu.total.to_i
      else
        cpu_freq+=node['cpu']['mhz'].to_i*node.cpu.total.to_i
      end
      if node.memory.total =~ /kB/
        memory+=node.memory.total.gsub("kB","").to_i*1024
      else
        memory+=node.memory.total.to_i
      end
    end
  rescue Exception => e
    puts "Oops !"
    puts node.name
    raise e
  end
}

puts "number of hosts : #{hosts}"
puts "total CPUs : #{cpus}"
puts "total CPU frequency : #{human_freq(cpu_freq)}"
puts "total memory : #{human_size(memory)}"