Cilium Feature Proposal

Have the Hubble server send its version to Hubble clients, so they may adapt their behaviour.

Is your proposed feature related to a problem?

Some Hubble changes inevitably introduce small breaking changes. For some of theses changes, the client could send a different query depending on the server version.

Currently, there is no way for a client to know the server version (except through the ServerStatus gRPC call), and consequently the client cannot adapt the queries depending on the server version. See this discussion for more context.

Describe the feature you'd like

There should be a way for a Hubble client to get the server version on connection.

(Optional) Describe your proposed solution

Have the Hubble server send the Cilium version through gRPC metadata (e.g. a custom header) on connection.