ConnectToMQ.scala

val connection = Connection()
val exchange = Exchange(exchangeName, Headers, durable = false)

connection.exchangeDeclare(exchange) onComplete {
  case Success(_) =>
    Source[GameEvent](EventPublisherActor.props)
      .map(toMessage)
      .to(Sink(connection.publish(exchange = exchangeName, "")))
      .run()(ActorFlowMaterializer())
  case Failure(ex) =>
    log.error("Cannot create exchange", ex)
    sys.exit(1)
}

def toMessage(event: GameEvent) = {
  val serialized = compact(render(Extraction.decompose(event)))
  Message(
    body = ByteString(serialized),
    contentType = Some(MediaType.JSON_UTF_8),
    contentEncoding = Some("UTF-8"),
    headers = Map(
      "gameId" -> event.id.value,
      "type" -> event.getClass.getSimpleName))
}