Add regex for path matching

[fabian4]

Proposed changes

Problem: Add regex for path matching

external (regex path match without any head/method/queryparams condition)

exact: /foo => = /foo
prefix: /foo => = /foo + ^~ /foo/
regex: /foo/(.*)$ => ~ /foo/(.*)$

Closes #3110

Checklist

Before creating a PR, run through this checklist and mark each as complete.

• I have read the CONTRIBUTING doc
• I have added tests that prove my fix is effective or that my feature works
• I have checked that all unit tests pass after adding my changes
• I have updated necessary documentation
• I have rebased my branch onto main
• I will ensure my PR is targeting the main branch and pulling from my branch from my own fork

Release notes

If this PR introduces a change that affects users and needs to be mentioned in the release notes,
please add a brief note that summarizes the change.

Add regex support for path matching

[nginx-bot]

Hi @fabian4!

Thanks for opening this pull request!
Be sure to check out our Contributing Guidelines while you wait for someone on the team to review this.

[salonichf5]

Hey @fabian4, thanks a lot for your contribution to NGINX Gateway Fabric!

I noticed there are still some parts left in this PR—were you looking for initial feedback before continuing development, or are you planning to submit this in parts?

[fabian4]

Hi @salonichf5, thanks a lot for the comment! I kept this PR as a draft since there are still some parts I’d like to finish up. In the meantime, getting some early feedback would be super helpful — that way I can adjust things early and make sure I’m heading in the right direction. Really appreciate your input!

[salonichf5]

Hi @salonichf5, thanks a lot for the comment! I kept this PR as a draft since there are still some parts I’d like to finish up. In the meantime, getting some early feedback would be super helpful — that way I can adjust things early and make sure I’m heading in the right direction. Really appreciate your input!

For sure, we will get some eyes on it. Thank you again for the contribution.

[sjberman]

@fabian4 We'll be sure to review this soon!

In the meantime, I ran the pipeline and there are some linting/unit test errors. Also, please be sure to follow this guide for formatting your main commit message and PR description. And please update the release note section the PR description as well, so we can include a notein our CHANGELOG when this ultimately gets released.