#! /usr/bin/env python

"""Simple CLI Tool Example to check routing table using ietf-routing YANG model and NETCONF

"""

from ncclient import manager

from ncclient.transport.errors import SSHError

import xmltodict

from xml.dom import minidom

def get_ipv4_default_rib(host, username, password, port=830):

"""Use NETCONF to connect to device, retrieve IPv4 default RIP, and return as dictionary

"""

filter = """

<filter>

<routing-state xmlns="urn:ietf:params:xml:ns:yang:ietf-routing"

xmlns:rt="urn:ietf:params:xml:ns:yang:ietf-routing">

<routing-instance>

<name>default</name>

<ribs>

<rib>

<name>ipv4-default</name>

</rib>

</ribs>

</routing-instance>

</routing-state>

</filter>

"""

# Open NETCONF connection to device

try:

with manager.connect(

host=host,

port=port,

username=username,

password=password,

hostkey_verify=False,

) as m:

r = m.get(filter)

except SSHError:

print(

"Unable to connect to device {} with NETCONF on port {}.".format(

host, port

)

)

exit(1)

# Pretty print raw xml to screen

# xml_doc = minidom.parseString(r.xml)

# print(xml_doc.toprettyxml(indent = " "))

# Process the XML data into Python Dictionary and use

response_dict = xmltodict.parse(r.xml)

routes = response_dict["rpc-reply"]["data"]["routing-state"][

"routing-instance"

]["ribs"]["rib"]["routes"]["route"]

return routes

def print_routes(routes):

"""Print out the routing table based on ietf-routing ipv4 ribs

"""

if len(routes) == 0:

print("No routes found.")

exit(1)

try:

print(

"{route:<20} {source:<10} {nexthop:<20}".format(

route="Prefix", source="Source", nexthop="Next Hop"

)

)

for route in routes:

print(

"{route:<20} {source:<10} {nexthop:<20}".format(

route=route["destination-prefix"],

source=route["source-protocol"],

nexthop=route["next-hop"]["next-hop-address"],

)

)

except Exception:

print("Problem in routing table, unable to print.")

exit(1)

# Script Entry Point

if __name__ == "__main__":

# Use Arg Parse to retrieve device details

import argparse

import os

parser = argparse.ArgumentParser()

parser.add_argument(

"--host", help="Host address for network device", required=True

)

parser.add_argument(

"--port", help="Override default NETCONF port of 830", default=830

)

parser.add_argument("--username", help="Device username", required=False)

parser.add_argument("--password", help="Device password", required=False)

args = parser.parse_args()

username = args.username

password = args.password

# If Username or Password not provided as arguments, check OS ENV

if username is None:

username = os.getenv("USERNAME")

if password is None:

password = os.getenv("PASSWORD")

if username is None or password is None:

print(

"You must provide a username and password as a command argument,"

)

print("or as Environment Variables of USERNAME or PASSWORD")

exit(1)

print("Getting route list from device...")

print("")

# Get route list

routes = get_ipv4_default_rib(

host=args.host, port=args.port, username=username, password=password

)

# Print route list

print_routes(routes)