class RollCall

# File lib/rollcall.rb, line 4
def self.call_roll
  addr = ['<broadcast>', 33333]# broadcast address

  sending_sock = UDPSocket.new
  sending_sock.setsockopt(Socket::SOL_SOCKET, Socket::SO_BROADCAST, true)
  data = 'roll call!'
  sending_sock.send(data, 0, addr[0], addr[1])

  addr = ['0.0.0.0', 33334]  # host, port
  BasicSocket.do_not_reverse_lookup = true
  #
  # Create socket and bind to address
  receiving_sock = UDPSocket.new
  receiving_sock.bind(addr[0], addr[1])

  server_info = {}

  # listen for 2 seconds
  loop do
    got_something_that_time = nil
    if IO.select([receiving_sock], nil, nil, 2) # 2 seconds
      data, addr = receiving_sock.recvfrom(1024) #1024 = max packet size

      got_something_that_time = true
      hostname,num_cores = data.split
      info = {cores: num_cores.to_i, role: "test_#{server_info.count}".to_sym}
      server_info.store(hostname, info)
    end
   break unless got_something_that_time # stop receiving if we haven't seen any data in a while
  end
  receiving_sock.close

  sending_sock.close
  server_info
end