Merge pull request #32 from 11wizards/feat/skip-topic-check

feature: skip topic check

pkg/googlecloud/publisher.go

@@ -37,6 +37,9 @@ type PublisherConfig struct {
  // ProjectID is the Google Cloud Engine project ID.
  ProjectID string
 
+ // If true, `Publisher` does not check if the topic exists before publishing.
+ DoNotCheckTopicExistence bool
+
  // If false (default), `Publisher` tries to create a topic if there is none with the requested name.
  // Otherwise, trying to subscribe to non-existent subscription results in `ErrTopicDoesNotExist`.
  DoNotCreateTopicIfMissing bool
@@ -222,6 +225,10 @@ func (p *Publisher) topic(ctx context.Context, topic string) (t *pubsub.Topic, e
  t.PublishSettings = *p.config.PublishSettings
  }
 
+ if p.config.DoNotCheckTopicExistence {
+ return t, nil
+ }
+
  exists, err := t.Exists(ctx)
  if err != nil {
  return nil, errors.Wrapf(err, "could not check if topic %s exists", topic)

pkg/googlecloud/pubsub_test.go

@@ -234,6 +234,24 @@ func TestPublishedMessageIdMatchesReceivedMessageId(t *testing.T) {
  }
 }
 
+func TestPublisherDoesNotAttemptToCreateTopic(t *testing.T) {
+ topic := fmt.Sprintf("missing_topic_%d", rand.Int())
+
+ // Set up publisher
+ pub, err := googlecloud.NewPublisher(googlecloud.PublisherConfig{
+ // DoNotCheckTopicExistence is set to true, so the publisher will not check
+ // if the topic exists and will also not attempt to create it.
+ DoNotCheckTopicExistence: true,
+ DoNotCreateTopicIfMissing: false,
+ }, nil)
+ require.NoError(t, err)
+ defer pub.Close()
+
+ // Publish a message
+ publishedMsg := message.NewMessage(watermill.NewUUID(), []byte{})
+ require.Error(t, pub.Publish(topic, publishedMsg), googlecloud.ErrTopicDoesNotExist)
+}
+
 func produceMessages(t *testing.T, topic string, howMany int) {
  pub, err := googlecloud.NewPublisher(googlecloud.PublisherConfig{}, nil)
  require.NoError(t, err)