Add middleware feature

[mike-code]

Ingress resource supports backend-config-snippet annotation, however there is no convenient way to share the same logic (ie. snippet) across many Ingress resources.

The idea is to have a kind of "middleware" where you define backend-snippet in global ConfigMap and then load it via haproxy.org/middleware: run_me.

Note: the controller would have to watch configmap for changes and update all Ingress'es should the run_me function/logic change.

[oktalz]

hi @mike-code,

for that purpose you can use backend CRD we do not plan to add more options for snippets, since you can do the same with CRDs, and custom resources are better in basically every way (scheme, validation ...)