Appending to MIDDLEWARE happens twice

[nniehoff]

Environment

• Python version: 3.6
• Nautobot version: 1.1.3

Steps to Reproduce

1. In nautobot_config.py append to MIDDLEWARE such as:

MIDDLEWARE.append("some new fancy middleware")

2. Start a python shell invoke nbshell
3. Check the MIDDLEWARE value:

from django.conf import settings
settings.MIDDLEWARE

Expected Behavior

The appended value "some new fancy middleware" should be added 1 time.

Observed Behavior

"some new fancy middleware" is appended to the array twice.

Workaround

if "some new fancy middleware" not in MIDDLEWARE:
    MIDDLEWARE.append("some new fancy middleware")

[nniehoff]

I suspect this is similar to the original issue with INSTALLED_APPS and ultimately we added EXTRA_INSTALLED_APPS which something like EXTRA_MIDDLEWARE might address but order matters in MIDDLEWARE so maybe not.

[jathanism]

Correct. What you should be doing is using EXTRA_MIDDLEWARE so that it is only done once. I know we have this documented, here for extra applications but not for middleware:

https://nautobot.readthedocs.io/en/stable/configuration/optional-settings/#extra-applications

I think we should use this as an excuse to update the documentation to also include "extra middleware" and an example.

[nniehoff]

Thanks @jathanism I'll work on a PR