Add WSGI ignore for specific user agent

[nils-van-zuijlen]

Is your feature request related to a problem? Please describe.

Kubernetes has a liveness and a readiness probe that can be configured to use HTTP.
All of these requests use the kube-probe/<version> user agent.

Describe the solution you'd like

I would like to be able to exclude all requests with the kube-probe user agent, and other specific user agents if needed (the go module mirror comes to my mind)

Describe alternatives you've considered

Entering manually every probing endpoint in the WSGI ignore path, but that does not allow to have a default value that excludes automatically all kube-probe endpoints.

[Kl0ven]

Having a user agent filter would be nice, but i avoided using regex filter to prevent slowdown.
It's the same problem: how to handle the version ?

We could also do a kube-probe specialized filter.

[nils-van-zuijlen]

I think an implementation could be excluded_agent in user_agent or user_agent.startswith(excluded_agent).
Or even excluded_agent == user_agent because the version does not change that often.

[Kl0ven]

Release in latest alpha version.