gateway-api: Support for BackendRef filters

[chaunceyjiang]

Fixes: #29080

Please ensure your pull request adheres to the following guidelines:

Gateway API BackendRef filters support

[chaunceyjiang]

/test

[acelinkio]

Confirmed this fix works!

Tested by deploying the 1.15.0-rc0 helm chart and using the container image generated in the PR workflow (https://github.com/cilium/cilium/actions/runs/7399979212/job/20132600608). values

operator:
  image:
   override: "quay.io/cilium/operator-generic-ci:a199ad6584be1047dc480e82b87d0e54ad008c24"

[youngnick]

The change looks good with one small query.

However, could you take this chance to add tests?

I think we need a test for one backend with Backend filters, multiple backends with different backend filters, and multiple backends with some with backend filters and some not.

The fixtures for the Gateway will need to be added in operator/pkg/model/ingestion/gateway_fixture_test.go, with the tests in operator/pkg/model/ingestion/gateway_test.go.

Then, you can take the []model.HTTPRoute that you get from that test, and use it as a fixture in operator/pkg/model/translation/fixture_test.go, and test it in operator/pkg/model/translation/translation_test.go.

Sorry to ask for a lot of tests here, but this feature is implementation-specific, so there aren't any tests upstream yet (I think that the tests you add here would be a great basis for optional upstream conformance tests that could move this feature to Extended there).

[chaunceyjiang]

I think we need a test for one backend with Backend filters, multiple backends with different backend filters, and multiple backends with some with backend filters and some not.

Ok, I will try to add some unit tests soon.

[chaunceyjiang]

/test

[youngnick]

Nice work on the tests! LGTM.

[youngnick]

/ci-ipsec-upgrade

[youngnick]

/ci-aks

[chaunceyjiang]

/ci-ipsec-upgrade

[chaunceyjiang]

/cc @sayboras @meyskens Please take a look.

[sayboras]

Thanks a lot

[acelinkio]

Hey! Can this be added to the 1.15.2 release? Thanks!