pyssh.py

# Utility function for ssh connection driver
# Based on Udemy Python Networking exercises
# Open SSHv2 connection to devices

import datetime

def open_ssh_conn(ip):
    # Change exception message
    try:
        # Define SSH parameters
        selected_user_file = open(user_file, 'r')

        # Starting from the beginning of the file
        selected_user_file.seek(0)

        username = selected_user_file.readlines()[0].split(',')[0]

        # Starting from the beginning of the file
        selected_user_file.seek(0)

        password = selected_user_file.readlines()[0].split(',')[1]

        # Logging into device
        session = paramiko.SSHClient()

        session.set_missing_host_key_policy(
            paramiko.AutoAddPolicy())

        session.connect(ip, username=username, password=password)

        connection = session.invoke_shell()

        # Setting terminal length for entire output - no pagination
        connection.send("terminal length 0\n")
        time.sleep(1)

        # Entering global config mode
        connection.send("\n")
        connection.send("configure terminal\n")
        time.sleep(1)

        # Open user selected file for reading
        selected_cmd_file = open(cmd_file, 'r')

        # Starting from the beginning of the file
        selected_cmd_file.seek(0)

        # Writing each line in the file to the device
        for each_line in selected_cmd_file.readlines():
            connection.send(each_line + '\n')
            time.sleep(2)

        # Closing the user file
        selected_user_file.close()

        # Closing the command file
        selected_cmd_file.close()

        # Checking command output for IOS syntax errors
        output = connection.recv(65535)

        if re.search(r"% Invalid input detected at", output):
            print("* There was at least one IOS syntax error on device %s" % ip)
        else:
            print("\nDONE for device %s" % ip)

        # Test for reading command output
        # print output + "\n"

        # Closing the connection
        session.close()

    except paramiko.AuthenticationException:
        print(
        "* Invalid username or password. \n* Please check the username/password file or the device configuration!")
        print("* Closing program...\n")


# Calling the SSH function
ip = "10.0.2.11"
open_ssh_conn(ip)