How to Netmiko – 5 minutes to all devices

# Just modify your inventory.yml file

# Change import settings
import yaml
import sys
import time
from netmiko import ConnectHandler, NetmikoTimeoutException, NetmikoAuthenticationException


# Reusable send command function
def send_command(dev: dict, cmd: str) -> str:
    """
    Send command to device using Netmiko
    :param dev: device info
    :param cmd: command to execute
    :return: Command output from device
    """
    hostname = dev['hostname']
    # remove key hostname from dictionary since it is not expected/valid for netmiko
    del dev['hostname']

    try:
        # Use context manager to open and close the SSH session
        with ConnectHandler(**dev) as ssh:
            ssh.enable()
            output = ssh.send_command(cmd)
        dev['hostname'] = hostname
        output = output.strip()
    except NetmikoTimeoutException:
        output = 'Connection timed out'
    except NetmikoAuthenticationException:
        output =  'Authentication failed'

    # re add key for future use
    dev['hostname'] = hostname

    return output


def get_devices(device_filter: str) -> dict:
    """
    Get match devices from inventory bases on name or IP
    :param device_filter: string to look for
    :return: matching inventory
    """
    with open('inventory.yml') as f:
        inventory = yaml.safe_load(f.read())
    matched_devices = []
    if device_filter != 'all':
        for device in inventory['hosts']:
            if device_filter in device['hostname'] or device_filter in device['host']:
                matched_devices.append(device)
        inventory['hosts'] = matched_devices

    # Show matched inventory and confirm
    text = '\nMatched inventory'
    print('{}\n{}'.format(text, '*' * len(text)))
    for device in inventory['hosts']:
        print('* host: {} - ip: {}'.format(device['hostname'], device['host']))
    confirm = input('\nPlease confirm (y/n): ')

    if confirm.lower() != 'y':
        sys.exit()

    return inventory


if __name__ == "__main__":
    # Type device filter by IP or hostname. Partial values or full. Optionally 'all'
    device_filter = input('\nSpecify device filter: ')

    # Load devices from file with the filter and display matching device
    inventory = get_devices(device_filter)

    # get the common variables for all devices
    credentials = inventory['common_vars']
    devices_counter = len(inventory['hosts'])

    # get command to execute from CLI
    command = input('\nCommand to run: ')
    
    # loop to keep throwing commands to the same selected inventory
    while command.lower() != 'exit':
        print(f'\nExecuting command: {command}\n')
        # Start timer variable
        execution_start_timer = time.perf_counter()
        # Loop to repeat the command in all the inventory
        for device in inventory['hosts']:
            # update the device dictionary with the credentials and send command
            device.update(credentials)
            print('*** host: {} - ip: {}'.format(device['hostname'], device['host']))
            # send command and store results
            result = send_command(device, command)
            # show result
            print(f'{result}\n')

        # Get and print finishing time
        elapsed_time = time.perf_counter() - execution_start_timer
        print(f"\n\"{command}\" executed in {devices_counter} devices in {elapsed_time:0.2f} seconds.\n")
        command = input('Command to run or \'exit\': ')