Dev: VlansInventory.py

Hi there, previously I shared a script that would get the vlans and show them on screen. Another useful requirement that I wanted to solve was to store that information on a CSV format as an inventory file.

from netmiko import ConnectHandler

import csv

# inventory with the ip of switches

devices = open('devices')

for ip in devices:

   session = {

       'ip': ip,

       'username': 'silesio',

       'password': 'cisco',

       'device_type': 'cisco_ios'

   }

   login = ConnectHandler(**session)

   # get the vlans

   output_vlan = login.send_command('show vlan brief', use_textfsm=True)

   # get the hostname

   output_hostname = login.send_command('show run | in hostname')

   hostname = output_hostname.split(' ')

   hostname = hostname[1]

   # add hostname to all dictionaries

   counter = 0

   size = len(output_vlan)

   for i in output_vlan:

       while counter < size:

           output_vlan[counter]['hostname'] = hostname

           counter += 1

   # the columns name

   columns = ['vlan_id', 'name', 'status', 'interfaces', 'hostname']

   # save the output to a new file

   with open('Vlans_Inventory.csv', 'a+', newline='') as output_file:

       inventory_file = csv.DictWriter(output_file, fieldnames=columns)

       inventory_file.writeheader()

       inventory_file.writerows(output_vlan)

print(output_vlan)

PS: I Just wanted to share a personal tip that may help you if you’re planning to start using python as well. If your background is anything else except Devops (html, java, python, c, c#...), my suggestion is to try these scripts and see the results. Don’t just take a course on Python or watch videos learning about tuples, dictionaries, thanos, loops, variables… Especially if you’re NE. Just start playing with 2 or 10 devices and automate most of the repetitive tasks that you do daily.

I hope you enjoyed this post, leave your comments below and I'll see you on the next one.