k8s gateway cluster names

[jenshu]

Description

(reopening the PR that was migrated to https://github.com/k8sgateway/k8sgateway/pull/10286, which was originally copied from https://github.com/solo-io/gloo/pull/10255)

This will make cluster names for kube services look like kube-svc_name_namespace_port or kube-svc_reviews_bookinfo_8080. If we add other resources besides a kube service, this also lets us get things like istio-se_helloworld_backend-ns_5000.

This will only happen for Gateway v2 translation. We can disable it using the env var GG_K8S_GW_LEGACY_CLUSTER_NAMES.

API changes

We can disable it using the env var GG_K8S_GW_LEGACY_CLUSTER_NAMES.

Code changes

• XDS translator now takes options that can customize this new behavior. We instantiate translator separately for v2, so that is the only path to enable it.
• Added another function to customize the generated name rather than modifying the existing cluster name function (it has over 100 usages! mostly in unit tests)
• Use internal labels to propagate the info in a structured way.

Docs changes

We should document this as a breaking change; users who rely on the old format should use the env var or update their EnvoyFilters or whatever config relies on XDS names...

Context

https://github.com/solo-io/solo-projects/issues/7105

Interesting decisions

• Use internal labels to propagate the info in a structured way. This was done so we can support more than just Upstream_Kube upstreams.
• Functional options for translator constructor. I didn't feel like updating the many references to this constructor, so varargs help. In hindsight, a second constructor could have also solved this.

Testing steps

TODO!

API changes

Code changes

CI changes

Docs changes

Context

Interesting decisions

Testing steps

Notes for reviewers

Checklist:

• [ ] I have performed a self-review of my own code
• [ ] I have commented my code, particularly in hard-to-understand areas
• [ ] I have made corresponding changes to the documentation
• [ ] I have added tests that prove my fix is effective or that my feature works

[solo-changelog-bot[bot]]

Issues linked to changelog: https://github.com/solo-io/solo-projects/issues/7105