How Do I Build a GCP Pubsub Subscription?

Introduction

Google Cloud Pub/Sub is a messaging service that allows you to send and receive messages between independent applications. To effectively use this service, you need to create a Pub/Sub topic and a subscription that listens to that topic. This guide provides a step-by-step process to set up a Pub/Sub subscription using TypeScript.

Step-by-Step Process

Step 1: Define the Pub/Sub Topic

The first step in setting up a Pub/Sub subscription is to define the topic. A topic is a named resource to which messages are sent by publishers. In your code, you’ll create a new topic instance.

Step 2: Create a Subscription

Once the topic is defined, the next step is to create a subscription. A subscription represents the stream of messages from a specific topic, which are then delivered to the subscribing application. You’ll configure the subscription to specify the topic it listens to and set other parameters like the acknowledgment deadline.

Step 3: Stack Exports

Finally, include stack exports in your code. Stack exports make it easy for other parts of your infrastructure to access the values you’re working with, such as the topic and subscription names.

Here is the program:

import * as pulumi from "@pulumi/pulumi";
import * as gcp from "@pulumi/gcp";

// Create a Pub/Sub topic
const exampleTopic = new gcp.pubsub.Topic("example_topic", {name: "my-example-topic"});
// Create a Pub/Sub subscription
const exampleSubscription = new gcp.pubsub.Subscription("example_subscription", {
    name: "my-example-subscription",
    topic: exampleTopic.name,
    ackDeadlineSeconds: 20,
});
export const topicName = exampleTopic.name;
export const subscriptionName = exampleSubscription.name;
const config = new pulumi.Config();
// The project ID to deploy resources
const projectId = config.get("projectId") || "my-gcp-project-id";
// The GCP region to deploy resources
const region = config.get("region") || "us-central1";

Key Points

• A Pub/Sub topic is the destination for messages from publishers.
• A subscription allows you to receive messages from a specific topic.
• Stack exports are useful for integrating with other parts of your infrastructure.

Conclusion

In this guide, you have successfully created a Google Cloud Pub/Sub topic and a subscription using TypeScript. By following the outlined steps, you can ensure that your applications are set up to send and receive messages efficiently using Google Cloud’s Pub/Sub service.