Passing a var from Nornir inventory file into the test

[bxijyoo]

First of all, thanks for putting this together. This is a great project with the right intentions for network engineers wanting to perform validations against their network.

What I was wondering was if there was any way to pass a host specific var into a test? For example for reusability, I was planning to have my inventory have generic hostnames, core_switch1, user_switch1, etc but with hostname that has the FQDN of the device.

For one of my tests, I am trying to lookup Netbox whether an entry exists for an interface IP and as hostname is not specific, I prefer to use the hostname or even any data/var that's specified under the host if that makes sense.

Example inventory file

core1:
  hostname: txcoreswitch1
  platform: ios
  username: admin
  password: admin
  data:
    fqdn: txcoreswitch1.company.local

[ubaumann]

Not sure if I understand your specific use case. Inside a NornirNutsContext, you can access the Nornir object. I did a brief example. Hope it helps:

Custom bundle implementation nb.py:

import pytest
import requests
from typing import Dict, Callable, Any
from nornir.core.task import Task, MultiResult, Result

from nuts.context import NornirNutsContext
from nuts.helpers.result import (
    AbstractHostResultExtractor,
    NutsResult,
)
from nuts.helpers.errors import Error

EXAMPLE = """
- test_module: demo.nb
  test_class: TestNBDevice
  test_data:
    - host: demo1
      model: C9200-48P
"""


class NBTaskError(Error):
    """My Netbox task failed"""


class NBExtractor(AbstractHostResultExtractor):
    def single_transform(self, single_result: MultiResult) -> Dict[str, Dict[str, Any]]:
        cli_result = self._simple_extract(single_result)
        return cli_result


class NBContext(NornirNutsContext):
    """
    - test_module: demo.nb
      test_class: TestNBDevice
      test_data:
        - host: <host>
          model: <model>
    """

    def nuts_task(self) -> Callable[..., Result]:
        return self.query_nb

    def query_nb(self, task: Task, **kwargs: Any) -> Result:
        """ """
        netbox_name = task.host.get("nb_name")
        device_data = requests.get(
            f"https://demo.netbox.dev/api/dcim/devices/?name={netbox_name}",
            headers={"Authorization": "Token b4a...............45"},
        )
        device_data.raise_for_status()
        return Result(host=task.host, result=device_data.json())

    def nuts_extractor(self) -> NBExtractor:
        return NBExtractor(self)


CONTEXT = NBContext


class TestNBDevice:
    @pytest.mark.nuts("model")
    def test_nb_device(self, single_result: NutsResult, model: str) -> None:
        nb_model = (
            single_result.result.get("results", [])[0]
            .get("device_type", {})
            .get("model")
        )
        assert (
            model == nb_model
        ), f"Model was expected to be {model}, but it was {nb_model}!"

Test yaml file test_nb.yaml:

- test_module: demo.nb
  test_class: TestNBDevice
  test_data:
    - host: demo1
      model: C9200-48P

Inventory:

demo1:
  hostname: demo.netbox.dev
  data:
    nb_name: C9200-SW1

[bxijyoo]

Yes apologize for not making it clear but we're definitely headed in the right direction. My intention was to build on the napalm_interfaces.py but instead of checking for IPs and masks defined in the test bundle (ip, mask), check against Netbox that for the given device, interface and IP address, it matches the result returned from napalm get_interfaces.

Instead

  test_data:
    - host: SW1
      name: Vlan3
      ip: 10.2.2.1
      mask: 24

Updated bundle

  test_data:
    - host: SW1
      name: Vlan3

As the context should still query device using napalm for "interfaces", how can I handle task.host.get("nb_name") and pass that down to the test class for assert?

I have the Netbox lookup working and code looks like this currently.

class TestCheckNetboxL3Interfaces:
    @pytest.mark.nuts("host,name")
    def test_interface_configured_ipv4(self, single_result, host, name, get_netbox_token):
        assert get_int_ip_netbox(host, get_netbox_token)[name] == get_ip_mask(single_result, name)

def get_int_ip_netbox(device_name, get_netbox_token):
    # get all interfaces and IP addresses configured on specified device from Netbox

    session = requests.Session()
    session.verify = False
    nb = pynetbox.api(url=NETBOXURL, token=get_netbox_token)
    nb.http_session = session

    # Get the device
    device = nb.dcim.devices.get(name=device_name)
    if not device:
        print(f"Device '{device_name}' not found in Netbox")
        return {}
    
    # Get all interfaces for the device
    interfaces = nb.dcim.interfaces.filter(device_id=device.id)
    
    int_ip_dict = {}
    
    for interface in interfaces:
        # Get IP addresses assigned to this interface
        ip_addresses = nb.ipam.ip_addresses.filter(assigned_object_id=interface.id)
        
        if ip_addresses:
            for ip in ip_addresses:
                int_ip_dict[interface.name] = ip['address']
            
    return int_ip_dict

def get_ip_mask(single_result, name):
    # combine ip address and subnet mask

    ip = str(next(iter(single_result.result[name]["ipv4"])))
    mask = single_result.result[name]["ipv4"][ip]["prefix_length"]
    ip_mask = f'{ip}/{mask}'

    return ip_mask