text: from charms.reactive import when, when_not, set_flag
  from charmhelpers import fetch
  from charmhelpers.contrib.charmsupport import nrpe
  from lib_infra_node import InfranodeHelper
  
  helper = InfranodeHelper()
  
  
  @when_not('infra-node.installed')
  def install_infra_node():
      set_flag('infra-node.installed')
  
  
  @when('nrpe-external-master.available')
  def update_nrpe_config():
      # python-dbus is used by check_upstart_job
      fetch.apt_install('python-dbus', fatal=True)
      hostname = nrpe.get_nagios_hostname()
      current_unit = nrpe.get_nagios_unit_name()
      nrpe_setup = nrpe.NRPE(hostname=hostname)
      helper.create_nrpe_checks(nrpe_setup, hostname, current_unit)
  