Support wildcards in ingress.kubernetes.io/cors-allow-origin

[nabadger]

What are you trying to do

I'm making use of ingress.kubernetes.io/cors-allow-origin across multiple-domains and it would handy if we could support something like:

ingress.kubernetes.io/cors-allow-origin: "*.example.com, *.example2.com"

I think perhaps the current option of * is not restrictive enough for my needs...but at the same time being able to use wildcards for different domains would save a lot of management overhead (we have lots of hosts...).

Related: #477

[wolf-cosmose]

I need a similar feature, though for my usecase it'd be best to support regexes.
From what I've seen, it'd be simple to implement in haproxy config, just a matter of adding -m reg to the ACLs in the template. However, haproxy-ingress's validation of the cors-allow-origin annotation doesn't allow regexes.

Currently I'm working it around using haproxy-ingress.github.io/config-backend with a copy of the CORS logic from the template, except with acl my_cors_allow_origin var(txn.my_hdr_origin) -m reg ^http://localhost:.*$ ...

Would a pull request adding regex support through an annotation like cors-allow-origin-regex be accepted?

[jcmoraisjr]

Hi, thanks for the proposal, sure it'd be a welcome contribution.