How to launch fire-and-forget server-streaming RPC inside RPC

[rygx]

I was trying to implement a cascade gRPC (say gRPC service A and gRPC service B), where service A launches B and immediately returns, and B is a server-streaming call.

My problem is that the service B is not successfully executed. Not sure if it was cancelled silently.

Inside service A (gRPC unary call), I implemented like below:

// inside service A
val threadLocalContext = Context.current().fork()
threadLocalContext.run {
  CoroutineScope(GrpcContextElement(threadLocalContext)).launch{
    // intends to call service B here but not successful. Seems nothing happens.
    val result = serviceBStub.invokeServerStreamingService(serviceBRequest)
  }
}

// service A exits

But it turns out that the service B server streaming call was never invoked. If I change B to a unary call it can successfully execute. So it seems that thread local is propagated, but I am not sure if this is the case in server streaming call situation.

Or if the server streaming call was cancelled? I did not see any exceptions being thrown.

Can someone tell me what went wrong and how to make it behave as intended? Thanks!