Report used JDK version

[ennru]

Most users will just keep the JDK version we provide in samples.
Over time this might change and we should keep track of used JDKs and their versions.

Refs https://github.com/lightbend/kalix/issues/4722, #1045

[patriknw]

I think we already populate that in the serviceRuntime, which is sent to the proxy in the discovery call.

kalix-jvm-sdk/sdk/java-sdk/src/main/scala/kalix/javasdk/impl/DiscoveryImpl.scala

Lines 57 to 58 in 3dc3664

	serviceRuntime = sys.props.getOrElse("java.runtime.name", "")
	+ " " + sys.props.getOrElse("java.runtime.version", ""),

[beritou]

I think we already populate that in the serviceRuntime, which is sent to the proxy in the discovery call.

This is correct. This information is currently already being logged. Here's an example:

Received Spec from user function: service name: [], service version: [], service runtime: [OpenJDK Runtime Environment 11.0.11+9], protocol version: [1.0], sdk: [kalix-java-sdk-1.0.2], proxy version [1.0.12], project [007ef2b5-d428-4700-a598-33e02b600421], service [realtimetransitdemo], service-uid [dc1fb64e-c2d5-4566-ad87-5e6d0ae38187], env [prod], region [us-east1],

[ennru]

Ok, that's great. We "just" need to make Grafana parse it and report it -- and show it in our Kalix Metrics dashboard.