k8s gateway cluster names

[jenshu]

Description

(reopening the PR that was migrated to k8sgateway#10286, which was originally copied from #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]

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

[jenshu]

getting errors like: "caller":"discovery/discovery.go:151","msg":"failed reconciling upstreams","version":"1.0.0-ci1","discovered_by":"kubernetesplugin","upstreams":14,"error":"reconciling resource kube-system-kube-dns-53: creating kube resource kube-system-kube-dns-53: Upstream.gloo.solo.io \"kube-system-kube-dns-53\" is invalid: [metadata.labels: Invalid value: \"~internal.solo.io/kubernetes-name\": prefix part a lowercase RFC 1123 subdomain must consist of lower case alphanumeric characters, '-' or '.', and must start and end with an alphanumeric character (e.g. 'example.com', regex used for validation is '[a-z0-9]([-a-z0-9]*[a-z0-9])?(\\.[a-z0-9]([-a-z0-9]*[a-z0-9])?)*'), when running this in a cluster