private static void ensureTopicAndSubscriptionExist(
      PubSub pubsub, String topic, String subscription) {
   
    if (pubsub.getTopic(topic) == null) {
      throw new IllegalStateException("Topic does not exist: " + topic);
    }
   
    if (pubsub.getSubscription(subscription) == null) {
      LOG.info("creating PubSub subscription={} for topic={}", subscription, topic);
      pubsub.create(SubscriptionInfo.of(topic, subscription));
      LOG.info("created PubSub subscription={} for topic={}", subscription, topic);
    }
  }