Prometheus metrics for netdev_keeper

[davidban77]

Environment

• Nautobot version: 1.5.13 (to get metrics.py support)
• nautobot-plugin-device-onboarding version: latest

Proposed Functionality

Expose Prometheus metrics for this app. Examples:

Check Reachability and Netmiko calls

In modules like netdev_keeper there could be value exposing metrics regarding the amount of time check_reachability has been called or even guess_device_type has been called or returned errors:

• nautobot_device_onboarding_reachability_ok_total 27.0
• nautobot_device_onboarding_reachability_failed_total 3.0
• nautobot_guess_device_type_total{guessed_device_type="cisco_xr"} 2.0
• nautobot_guess_device_type_errors_total{error_code="NetMikoAuthenticationException"} 2.0

These are just a few examples.

Use Case

Allow users of the platform to generate time series from their Nautobot instance. In the end this could troubleshoot and get more insight of their Nautobot platform.

[scetron]

The total devices onboarded metric exists already, but it is generated on the worker after netdev keeper runs. Will have to sync to determine the best method of collecting that.