rewritepolicy CRD: regex rewrite-criteria handling

[talbx]

Hi,

I have some issues using the rewritepolicy CRD and I can't tell if it's just not working out or if I miss something.
I have a scenario where I want to rewrite any request containing /somethingblablabla to /someOtherPathblablabla; what is important, is that I want to preserve the appendix of /something, so that in the end it is also attached to the target path.

Therefore I planned to use regex in the rewrite-criteria property like this:

    - servicenames:
        - my-service
      rewrite-policy:
        operation: replace
        target: http.req.url
        modify-expression: '/someOtherPath\1'
        direction: REQUEST
        rewrite-criteria: HTTP.REQ.URL.PATH_REGEX_MATCH('regex(re~(/something.*)~)')

So this doesn't seem to work, the config push failed, when deployed to the k8s cluster. I also did not see any documentation on using regex in the rewrite-criteria field. I then tried out playing around with the multiple-occurence-modify property but that did not work either and that's why I'm here.

How do I specify a rewritepolicy which matches some path containing a regex pattern, and rewrites it to a target path while preserving all of its appendix (I read \n is the equivalent of $n in apache rewrites for preserving path elements) ?

Update:

I found out using multiple-occurence-modify it is possible to provide a regular expression like

    - rewrite-policy:
        comment: HTTP url replace string
        direction: REQUEST
        modify-expression: '"/someOtherPath\1"'
        multiple-occurence-modify: regex(re~(^/something.*)~)
        operation: replace_all
        rewrite-criteria: http.req.url.contains("/something")
        target: http.req.url
      servicenames:
        - my-service

but still, the preserving of the suffix right after /something is questionable. The syntax \n doesn't seem to work here.

Cheers