How to use the charmhelpers.contrib.charmsupport.nrpe function in charmhelpers

def update_nrpe_config(unused=None):
    services = ('nginx',)

    hostname = nrpe.get_nagios_hostname()
    current_unit = nrpe.get_nagios_unit_name()
    nrpe_setup = nrpe.NRPE(hostname=hostname)
    nrpe.add_init_service_checks(nrpe_setup, services, current_unit)
    nrpe_setup.write()

@when('kubernetes-worker.config.created')
@when('nrpe-external-master.available')
@when_any('config.changed.nagios_context',
          'config.changed.nagios_servicegroups')
def update_nrpe_config(unused=None):
    services = ('snap.kubelet.daemon', 'snap.kube-proxy.daemon')
    hostname = nrpe.get_nagios_hostname()
    current_unit = nrpe.get_nagios_unit_name()
    nrpe_setup = nrpe.NRPE(hostname=hostname)
    nrpe.add_init_service_checks(nrpe_setup, services, current_unit)
    nrpe_setup.write()

from charms.kubernetes.common import get_version
from charms.kubernetes.common import retry
from charms.kubernetes.flagmanager import FlagManager

from charmhelpers.core import hookenv
from charmhelpers.core import host
from charmhelpers.core import unitdata
from charmhelpers.core.templating import render
from charmhelpers.fetch import apt_install
from charmhelpers.contrib.charmsupport import nrpe


# Override the default nagios shortname regex to allow periods, which we
# need because our bin names contain them (e.g. 'snap.foo.daemon'). The
# default regex in charmhelpers doesn't allow periods, but nagios itself does.
nrpe.Check.shortname_re = '[\.A-Za-z0-9-_]+$'

os.environ['PATH'] += os.pathsep + os.path.join(os.sep, 'snap', 'bin')


def service_cidr():
    ''' Return the charm's service-cidr config '''
    db = unitdata.kv()
    frozen_cidr = db.get('kubernetes-master.service-cidr')
    return frozen_cidr or hookenv.config('service-cidr')


def freeze_service_cidr():
    ''' Freeze the service CIDR. Once the apiserver has started, we can no
    longer safely change this value. '''
    db = unitdata.kv()
    db.set('kubernetes-master.service-cidr', service_cidr())

@when('kubernetes-master.components.started')
@when('nrpe-external-master.available')
@when_any('config.changed.nagios_context',
          'config.changed.nagios_servicegroups')
def update_nrpe_config(unused=None):
    services = (
        'snap.kube-apiserver.daemon',
        'snap.kube-controller-manager.daemon',
        'snap.kube-scheduler.daemon'
    )
    hostname = nrpe.get_nagios_hostname()
    current_unit = nrpe.get_nagios_unit_name()
    nrpe_setup = nrpe.NRPE(hostname=hostname)
    nrpe.add_init_service_checks(nrpe_setup, services, current_unit)
    nrpe_setup.write()

def update_nrpe_config(unused=None):
    services = ('snap.kubelet.daemon', 'snap.kube-proxy.daemon')
    hostname = nrpe.get_nagios_hostname()
    current_unit = nrpe.get_nagios_unit_name()
    nrpe_setup = nrpe.NRPE(hostname=hostname)
    nrpe.add_init_service_checks(nrpe_setup, services, current_unit)
    nrpe_setup.write()

def update_nrpe_config(unused=None):
    services = (
        'snap.kube-apiserver.daemon',
        'snap.kube-controller-manager.daemon',
        'snap.kube-scheduler.daemon'
    )
    hostname = nrpe.get_nagios_hostname()
    current_unit = nrpe.get_nagios_unit_name()
    nrpe_setup = nrpe.NRPE(hostname=hostname)
    nrpe.add_init_service_checks(nrpe_setup, services, current_unit)
    nrpe_setup.write()

from charms.reactive import set_state, remove_state, is_state
from charms.reactive import when, when_any, when_not, when_none

from charms.kubernetes.common import get_version

from charms.reactive.helpers import data_changed
from charms.templating.jinja2 import render

from charmhelpers.core import hookenv, unitdata
from charmhelpers.core.host import service_stop, service_restart
from charmhelpers.contrib.charmsupport import nrpe

# Override the default nagios shortname regex to allow periods, which we
# need because our bin names contain them (e.g. 'snap.foo.daemon'). The
# default regex in charmhelpers doesn't allow periods, but nagios itself does.
nrpe.Check.shortname_re = '[\.A-Za-z0-9-_]+$'

kubeconfig_path = '/root/cdk/kubeconfig'
kubeproxyconfig_path = '/root/cdk/kubeproxyconfig'
kubeclientconfig_path = '/root/.kube/config'
gcp_creds_env_key = 'GOOGLE_APPLICATION_CREDENTIALS'
snap_resources = ['kubectl', 'kubelet', 'kube-proxy']

os.environ['PATH'] += os.pathsep + os.path.join(os.sep, 'snap', 'bin')
db = unitdata.kv()


@hook('upgrade-charm')
def upgrade_charm():
    # migrate to new flags
    if is_state('kubernetes-worker.restarted-for-cloud'):
        remove_state('kubernetes-worker.restarted-for-cloud')

def update_nrpe_config(unused=None):
    services = ('snap.kubelet.daemon', 'snap.kube-proxy.daemon')
    hostname = nrpe.get_nagios_hostname()
    current_unit = nrpe.get_nagios_unit_name()
    nrpe_setup = nrpe.NRPE(hostname=hostname)
    nrpe.add_init_service_checks(nrpe_setup, services, current_unit)
    nrpe_setup.write()

def update_nrpe_config(unused=None):
    services = (
        'snap.kube-apiserver.daemon',
        'snap.kube-controller-manager.daemon',
        'snap.kube-scheduler.daemon'
    )
    hostname = nrpe.get_nagios_hostname()
    current_unit = nrpe.get_nagios_unit_name()
    nrpe_setup = nrpe.NRPE(hostname=hostname)
    nrpe.add_init_service_checks(nrpe_setup, services, current_unit)
    nrpe_setup.write()

def update_nrpe_config():
    # python-dbus is used by check_upstart_job
    apt_install('python-dbus')
    hostname = nrpe.get_nagios_hostname()
    current_unit = nrpe.get_nagios_unit_name()
    nrpe_setup = nrpe.NRPE(hostname=hostname)
    nrpe.copy_nrpe_checks()
    nrpe.add_init_service_checks(nrpe_setup, services(), current_unit)
    nrpe.add_haproxy_checks(nrpe_setup, current_unit)
    api_port = determine_api_port(config('bind-port'),
                                  singlenode_mode=True)
    nrpe_setup.add_check(
        shortname="swift-proxy-healthcheck",
        description="Check Swift Proxy Healthcheck",
        check_cmd="/usr/lib/nagios/plugins/check_http \
                  -I localhost -u /healthcheck -p {} \
                  -e \"OK\"".format(api_port)
    )
    nrpe_setup.write()