Ettevõttesüsteemide integreerimine - Kursused

Session 4: Integration with Enterprise Networks Hardware

In this session we discuss integration with network devices using REST APIs. Before we start with the API development, you need to have some basic knowledge and skills of how APIs work, how they are accessed, what are the authorisation methods, and how to pass some header information with our requests.

To answer these questions, we are going to use different tools e.g. cURL, Postman, and simple Python scripts to utilise REST APIs in the context of networking, particularly, network devices. In this video, we provide a step-by-step guide on how to use these APIs and interact with a networking platform.

Please use the following info/credentials to call the APIs.

IOSXE Device
- Host: sandbox-iosxe-latest-1.cisco.com
- Username: developer
- Password: C1sco12345
- SSH Port: 22
- RESTCONF: 443
Test SSH Connection:
- Open Terminal
- ssh developer@sandbox-iosxe-latest-1.cisco.com -p 22
- Enter the password: C1sco12345
Use cURL and REST/RESTCONF to Retrieve ietf-interfaces data in a JSON format
- Open Terminal
- Retrieve data about all interfaces:
  - curl -vk -u developer:C1sco12345 -H "accept:application/yang-data+json" https://sandbox-iosxe-latest-1.cisco.com:443/restconf/data/ietf-interfaces:interfaces
- Retrieve data of a specific interface:
  - curl -vk -u developer:C1sco12345 -H "accept:application/yang-data+json" https://sandbox-iosxe-latest-1.cisco.com:443/restconf/data/ietf-interfaces:interfaces/interface=GigabitEthernet1
- Note: if you don't pass the header -H "accept:application/yang-data+json", the data will be retrieved in default format xml
Using Postman to execute APIs
- Let's call the same API as we did in the cURL example:
  - Install Postmane: sudo snap install postman
  - Open Postman and use this https://sandbox-iosxe-latest-1.cisco.com:443/restconf/data/ietf-interfaces:interfaces request URL with GET method.
  - Navigate to Authorisation, select Basic Auth, and enter your username(developer) and password (C1sco12345).
  - Navigate to Headers and add the Accept header key with application/yang-data+json value.
  - Send request

HTTP Request – Clicking this would display a dropdown list of different requests such as GET, POST, COPY, DELETE, etc. In Postman API testing, the most commonly used requests are GET and POST.
Request URL – Also known as an endpoint, this is where you will identify the link to where the API will communicate with.
Authorisation – In order to access APIs, proper authorisation is needed. It may be in the form of a username and password, bearer token, etc. In our case, we are using Basic Auth in the form of a username and password.
Headers – You can set headers such as content type (Accept) JSON depending on the needs of the organisation.
Status - HTTP Response Status Code and Message
Response Data in JSON format

Using JavaScript

Enable cross-origin requests to anywhere: https://cors-anywhere.herokuapp.com/corsdemo

<!DOCTYPE html>
<html>
<body>
<h1>Calling a REST API using JavaScript</h1>
<button type="button" onclick="loadDoc()">Request data</button>
<p id="demo"></p>

<script>
function loadDoc() {
  var xhttp = new XMLHttpRequest();
  var username="developer";
  var password="C1sco12345";
  xhttp.onreadystatechange = function() {
    if (this.readyState == 4 && this.status == 200) {
      document.getElementById("demo").innerHTML = this.response;
    }
  };
  xhttp.open("GET", "https://cors-anywhere.herokuapp.com/https://sandbox-iosxe-latest-1.cisco.com:443/restconf/data/ietf-interfaces:interfaces", false);
  xhttp.setRequestHeader("Authorization", "Basic " + btoa(username + ":" + password));
  xhttp.setRequestHeader("Accept", "application/yang-data+json");
  xhttp.setRequestHeader("Access-Control-Allow-Origin", "*");
  xhttp.send();
}
</script>
</body>
</html>

Using Python to consume APIs

The following Python script calls the same API as we described in the previous sections. You have greater flexibility in Python or any other programming language to consume APIs and manipulate the extracted data according to your organisation needs.

To run these scripts, please copy and save it as a python file (with .py extension) and run it via terminal:

Python 3.^*: python3 script_name.py
Python 2.^*: python script_name.py

import requests
import json
import urllib3

urllib3.disable_warnings()

HOST = 'sandbox-iosxe-latest-1.cisco.com'
USER = 'developer'
PASS = 'C1sco12345'

url = "https://sandbox-iosxe-latest-1.cisco.com:443/restconf/data/ietf-interfaces:interfaces"
headers = {'Content-Type': 'application/yang-data+json', 'Accept': 'application/yang-data+json'}

response = requests.get(url, auth=(USER, PASS), headers=headers, verify=False)
# print(response.content)
interfaces = response.json()
print("*******All Interfaces*******")
print(json.dumps(interfaces, indent=2))
print("*******The first interface name*******")
print(interfaces['ietf-interfaces:interfaces']['interface'][0]['name'])
print("*******The first interface IP address*******")
print(interfaces['ietf-interfaces:interfaces']['interface'][0]['ietf-ip:ipv4']['address'][0]['ip'])

Calling Cisco DNA Center APIs

In this section we will address Token-based authentication for APIs. Please use the following credentials while you are calling the DNA Center APIs:

Host: sandboxdnac2.cisco.com
Username: devnetuser
Password: Cisco123!

Authentication API

Using Postman:

Method POST
Request URL: https://sandboxdnac2.cisco.com/dna/system/api/v1/auth/token
Authorisation: Basic Auth with username and password
Header: Key:Accept, Value: application/json
Response: Successful Token Generation

Using Python

import requests
import json
import urllib3

urllib3.disable_warnings()
url = 'https://sandboxdnac2.cisco.com/dna/system/api/v1/auth/token'
username = 'devnetuser'
password = 'Cisco123!'

headers={'content-type': 'application/json'}
token = requests.post(url, auth=(username,password),headers=headers,verify=False,)
data = token.json()
print(data['Token'])

Get VLAN Details

In this example we will present how to use Token-based authentication to call an API.

Using Postman:

Method GET
Request URL: https://sandboxdnac2.cisco.com/
Authorisation: Inherit auth from parent
Header: Key:X-Auth-Token, Value: Obtained token from the Authentication API without double quotation
Response: Returns the list of VLAN names in JSON format

Using Python

from textwrap import indent
import requests
import json
import urllib3

urllib3.disable_warnings()

token = "Your Token obtained from the Authentication API"
url = 'https://sandboxdnac2.cisco.com/dna/intent/api/v1/topology/vlan/vlan-names'
headers= {'X-Auth-Token': '{}'.format(token),'content-type': 'application/json',}
response = requests.get(url,headers=headers,verify=False,)
print(json.dumps(response.json(), indent=2))

Additional Scripts

Here you can access a collection of python scripts for network management as well as samples that use exposed external APIs (NETCONF/RESTCONF, SNMP, SSH, REST, etc). The following example demonstrates using Netmiko library to work with interfaces and send configuration commands to device. Device info are stored in a .env file.

Make sure you have installed the below required libraries:

python3 -m pip install netmiko
python3 -m pip install python-decouple

# Import libraries
import os
from netmiko import ConnectHandler
from decouple import config
import json

dev_type = config('device_type')
host = config('host')
user = config('username')
passwd = config('passwd')
port = config('port')

cisco_881 = {
    'device_type': dev_type,
    'host':   host,
    'username': user,
    'password': passwd,
    'port' : port,          # optional, defaults to 22
    'secret': ''     # optional, defaults to ''
}

# Open CLI connection to device
net_connect = ConnectHandler(**cisco_881)
# Enable global configuration mode
net_connect.enable()
# Send command to device
interfaces = net_connect.send_command('show ip int brief', use_textfsm=True)
noi = len(interfaces)
print("This device has " +str(noi) + " Interfaces")
# Print the list of interfaces to the screen
print(interfaces)
config_command = ['int GigabitEthernet3', 'no shut']
output = net_connect.send_config_set(config_command)
# Print the raw command output to the screen
print(output)
# Print the list of interfaces to the screen
print(interfaces)

Ettevõttesüsteemide integreerimine 2021/22 kevad

Session 4: Integration with Enterprise Networks Hardware

Using JavaScript

Using Python to consume APIs

Calling Cisco DNA Center APIs

Authentication API

Using Postman:

Using Python

Get VLAN Details

Using Postman:

Using Python

Additional Scripts