Permit Source configuration for weighted routing in VirtualServer

[eanveden]

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

Hi! my team is looking to enable traffic splitting for our NGINX gateway using Virtualserver/VSR. One thing that we are currently interested in is configuring a custom key for the split_client hash to enable weighted routing based on our a custom string/key.

One such as a case is when we have a inc header "http_call_id", for which we would like to route calls to the same upstream, but still split our calls (uniquely identified by call_id) between several upstreams for A/B testing, Blue/green, and Canary testing.

Describe the solution you'd like

One solution could be to allow this field to be configured under each route - for example something like below:

	path: /tea
	splitsKey: "$http_call_id"
	splits:
	- weight: 80
	action:
		pass: coffee-v1
	- weight: 20
	action:
		pass: coffee-v2

Describe alternatives you've considered
Alternatives such as http-snippets works - but its impractical when you want to avoid enabling snippets in general since we have a lot of partner teams using our gateway, and snippets tend to break the overall IC configuration generation.

Additional context
I would be happy to make a contribution myself, but I don't want to waste time implementing something if you guys think its a waste.

[github-actions]

Hi @eanveden thanks for reporting!

Be sure to check out the docs and the Contributing Guidelines while you wait for a human to take a look at this 🙂

Cheers!

[haywoodsh]

Thanks for opening the issue @eanveden. I'm trying to understand your proposal for the traffic-splitting feature.

I deployed the traffic-splitting example, and this is the generated NGINX conf:

split_clients $request_id $vs_default_cafe_splits_0 {
    90% /internal_location_splits_0_split_0;
    10% /internal_location_splits_0_split_1;
}

Having looked at our current implementation, I see that the string$request_id is hardcoded. Did you mean that you would like it to be customisable?

You mentioned that using snippets worked. Could you share your snippets so we can better understand the enhancement you would like to see in the traffic splitting feature?

[eanveden]

Yes, that's what I meant - making $request_id customizable 👍

By snippets I mean basically injecting our configuration using http snippet, like -

http-snippets: |
   split_clients **$http_this_is_my_header** $vs_default_cafe_splits_0 {
       90% /internal_location_splits_0_split_0;
       10% /internal_location_splits_0_split_1;
   }

[haywoodsh]

Would it be useful to you to able to route requests based on an exact or regular expression match of variables with condition in match? https://docs.nginx.com/nginx-ingress-controller/configuration/virtualserver-and-virtualserverroute-resources/#condition
Or is it necessary to hash the variable for your use case?

Regarding the CRD change, note that splits is also available under matches https://docs.nginx.com/nginx-ingress-controller/configuration/virtualserver-and-virtualserverroute-resources/#match. Even though this might not meet your use case as far as I understand, we will need to consider it so that the new string field for the string to be hashed is also associated with splits here.