localip.rb

def get_ifs_and_addrs
  interfaces = {}
  curr_inf = ""
  IO.popen("ip a").each do |line|
    if line =~ /^\d+?: (.*):/
      interfaces[$1] = Array.new
      curr_inf = $1
    end
    if line =~ /\s+inet\s(.*)\//
      interfaces[curr_inf] << $1
    end
  end
  return interfaces
end

def local_ip
  require 'ipaddr'
  local_space = IPAddr.new("10.0.0.0/8")
  # Return the loopback is exists                                                                        
  interfaces = get_ifs_and_addrs
  if interfaces["lo"] && interfaces["lo"].size > 1
    interfaces["lo"].each do |addr|
      return addr if local_space.include?(addr)
    end
  end
  # Use the default ip if it is local                                                                    
  return node[:ipaddress] if local_space.include?(node[:ipaddress])
  interfaces.sort.each do |iface,addrs|
    addrs.each do |addr|
      return addr if local_space.include?(addr)
    end
  end
  return node[:ipaddress]
end