Non-standard platform slug not fully supported

[JostLuebbe]

Hello,

I wasn't sure under which Github repository to leave this issue so if I should open it under the nornir_netmiko library instead let me know.

Issue

The nornir_nautobot library allows us to map non-standard platform slugs to the correct [Nornir Dispatcher class].(https://docs.nautobot.com/projects/plugin-nornir/en/latest/user/app_feature_dispatcher/#configuring-the-dispatcher)

This is very convenient, and I was attempting to take advantage of this but noticed my Nautobot Golden Config backup jobs were still failing. Here is the code trace I've done and what I believe is the root cause of the failure:

1. nornir_nautobot selects the correct dispatched based on the extra configurations we make, and eventually ends up in the get_config method of the NetmikoNautobotNornirDriver class:
   https://github.com/nautobot/nornir-nautobot/blob/develop/nornir_nautobot/plugins/tasks/dispatcher/default.py
2. This method calls the netmiko_send_command task.
3. This then attempts to establish a Netmiko connection object:
   https://github.com/ktbyers/nornir_netmiko/blob/develop/nornir_netmiko/tasks/netmiko_send_command.py
   https://github.com/ktbyers/nornir_netmiko/blob/develop/nornir_netmiko/connections/netmiko.py
4. This connection object attempts to use the platform string to map to the correct Netmiko device_type:

napalm_to_netmiko_map = {
    "ios": "cisco_ios",
    "nxos": "cisco_nxos",
    "nxos_ssh": "cisco_nxos",
    "eos": "arista_eos",
    "junos": "juniper_junos",
    "iosxr": "cisco_xr",
}

However, because we are using a non-standard platform string this mapping fails and throws an exception.

The Ask

Would it be possible to allow us to either also configure the napalm_to_netmiko_map to include our non-standard platform strings, or have some way of passing an overriding platform value when calling the netmiko_send_command task and establishing the Netmiko connection.

Another possibility may be to use the Napalm driver instead, but I also believe there modifications would be necessary to pass a configured platform slug.

I am of course open to any other suggestions or ideas you may have for working around this issue and please let me know if you'd like more information.