the way you have here will not work. we don't want to provide the telemetry context at the moment of calling trackCommandsUnbounded. We want to have a different one for each Ctx[Context, SubmitRequest] passed into the Flow, that's why it makes more sense to have it as part of the Ctx object

you could change Ctx to be like this

final case class Ctx[+Context, +Value](context: Context, value: Value, telemetryContext: TelemetryContext = NoOpTelemetryContext)

This won't break existing code and will allow passing the context around. The only missing thing would be to actually propagate that context further at the appropriate places

@danilofaria I dropped another draft PR with the changes you suggested. There are a few drawbacks of this approach, though:

• it doesn't break the existing code only partially, at least the pattern matches have to be modified
• I cannot use the TelemetryContext, as the Akka Streams' Outlet requires the Ctx to be serializable. The TelemetryContext is not, as it contains the Tracer, for example
• I prefer to avoid default arguments, which is minor

Please let me know if we cannot use the changes from here for sure, as each gRPC call will be traced anyway (the client interceptor will create sub-spans).

There is also one more thing to tackle. I did not touch the CommandCompletionService. I assume you'd like to trace it, too.

cc @miklos-da @lucb-da

i confirm the changes from this PR are not usable since we need a new context per submission and we want to provide one from the parent context. i will look at your other PR. i dont think think you need to trace the CommandCompletionService since that doesnt touch the context we're passing to the flow

Thanks, rejecting this one then.