Google Cloud Pub/Sub Integration

Definitions

• Topic: A named resource to which messages are sent by publishers.
• Subscription: A named resource representing the stream of messages from a specific topic, to which subscribers can attach.
• Publisher: An application that sends messages to a topic.
• Subscriber: An application that receives messages from a subscription.

Step-by-Step Setup

1. Go to the Google Cloud Console.
2. Create a new project or select an existing one.
3. Enable the Pub/Sub API for your project.
4. Create a topic:

   gcloud pubsub topics create my-topic

5. Create a subscription:

   gcloud pubsub subscriptions create my-subscription --topic=my-topic

Publishing a Message

To publish a message to a topic, you can use the following code snippet:

                import GoogleCloudPubSub

                let publisher = Publisher(topic: "my-topic")
                let message = "Hello, Pub/Sub!"
                publisher.publish(message: message) { response, error in
                    if let error = error {
                        print("Error publishing message: \(error)")
                    } else {
                        print("Message published: \(response)")
                    }
                }
                

Receiving Messages

To receive messages from a subscription, you can use the following code snippet:

                import GoogleCloudPubSub

                let subscriber = Subscriber(subscription: "my-subscription")
                subscriber.listen { message, error in
                    if let error = error {
                        print("Error receiving message: \(error)")
                    } else {
                        print("Received message: \(message?.data)")
                        subscriber.acknowledge(message: message)
                    }
                }
                

Recommendations

• Use multiple subscriptions to distribute load across multiple services.
• Implement error handling and retries for message processing.
• Monitor message delivery and processing times using Google Cloud Monitoring.