Executing Arbitrary Junos 'Show' Commands with PyEZ and ncclient

ncclient_demo.py

#!/usr/bin/env python
# Demonstrates the use of the 'command' tag to execute arbritrary 'show' commands.
# This code was inspired by Ebben Aries's command-jnpr.py at
# https://github.com/leopoul/ncclient/blob/master/examples/juniper/command-jnpr.py
#
# usage: python ncclient_demo.py <show command> <xpath expression>
# python ncclient_demo.py 'show route 2600::/64' '//rt-entry/nh'
# 
# Jeff Loughridge
# August 2014

import sys

from lxml import etree as etree
from ncclient import manager
from ncclient.xml_ import *

def connect(host, port, user, password, source):

    try:
        show_command = sys.argv[1]
    except IndexError:
        print "please specify show command as first argument."
        sys.exit(1)

    try:
        xpath_expr = sys.argv[2]
    except IndexError:
        xpath_expr=''

    conn = manager.connect(host=host,
            port=port,
            username=user,
            password=password,
            timeout=3,
            device_params = {'name':'junos'},
            hostkey_verify=False)

    try:
        result = conn.command(command=show_command, format='xml')
    except Exception, e:
        print "ncclient_demo.py: Encountered critical error"
        print e
        sys.exit(1)

    tree = etree.XML(result.tostring)

    if xpath_expr:
        filtered_tree_list = tree.xpath(xpath_expr)
        for element in filtered_tree_list:
            print etree.tostring(element)
    else:
        print etree.tostring(tree)

if __name__ == '__main__':
    connect('ROUTER', 830, 'USER', 'PASSWORD', 'candidate')