@google-cloud/pubsub

What is @google-cloud/pubsub?

The @google-cloud/pubsub npm package is a client library for accessing Google Cloud Pub/Sub, a fully-managed real-time messaging service that allows you to send and receive messages between independent applications. This package provides an easy-to-use API to interact with Google Cloud Pub/Sub and is designed to handle the complexities of the underlying API operations.

What are @google-cloud/pubsub's main functionalities?

Publishing Messages

This feature allows you to publish messages to a topic. The code sample demonstrates how to create a PubSub client, get a reference to a topic, and publish a message to that topic.

const {PubSub} = require('@google-cloud/pubsub');
const pubsub = new PubSub();
const topic = pubsub.topic('my-topic');
const messageBuffer = Buffer.from('Hello, world!');
topic.publish(messageBuffer);

Subscribing to Topics

This feature enables you to subscribe to a topic and receive messages. The code sample shows how to create a PubSub client, get a reference to a subscription, and set up an event handler to process received messages.

const {PubSub} = require('@google-cloud/pubsub');
const pubsub = new PubSub();
const subscription = pubsub.subscription('my-subscription');
subscription.on('message', message => {
  console.log('Received message:', message.data.toString());
  message.ack();
});

Managing Topics and Subscriptions

This feature covers the management of topics and subscriptions, including creating and deleting them. The code sample illustrates how to create a new topic and delete an existing subscription.

const {PubSub} = require('@google-cloud/pubsub');
const pubsub = new PubSub();
// Create a new topic
pubsub.createTopic('new-topic').then(response => {
  console.log('Topic created:', response[0].name);
});
// Delete a subscription
pubsub.subscription('old-subscription').delete();

Other packages similar to @google-cloud/pubsub

aws-sdk

The AWS SDK for JavaScript provides a similar messaging service through Amazon SNS (Simple Notification Service) and SQS (Simple Queue Service). While AWS SDK supports both pub/sub and queue-based messaging, @google-cloud/pubsub is specifically optimized for Google Cloud's Pub/Sub service.

azure-sb

Azure-sb is a client library for Azure Service Bus, which also supports pub/sub messaging patterns. Compared to @google-cloud/pubsub, azure-sb is tailored for integration with Azure's ecosystem and supports additional features like message sessions and dead-letter queues.

rascal

Rascal is an abstraction layer over amqplib for RabbitMQ, a popular open-source message broker. Unlike @google-cloud/pubsub, which is a cloud-native service, Rascal with RabbitMQ can be used both on-premises and in the cloud, offering more flexibility in deployment models.

README

Google Cloud Pub/Sub: Node.js Client

Cloud Pub/Sub is a fully-managed real-time messaging service that allows you to send and receive messages between independent applications.

This document contains links to an API reference, samples, and other resources useful to developing Node.js applications. For additional help developing Pub/Sub applications, in Node.js and other languages, see our Pub/Sub quickstart, publisher, and subscriber guides.

A comprehensive list of changes in each version may be found in the CHANGELOG.

• Google Cloud Pub/Sub Node.js Client API Reference
• Google Cloud Pub/Sub Documentation
• github.com/googleapis/nodejs-pubsub

Read more about the client libraries for Cloud APIs, including the older Google APIs Client Libraries, in Client Libraries Explained.

Table of contents:

• Quickstart
  • Before you begin
  • Installing the client library
  • Using the client library
• Samples
• Versioning
• Contributing
• License

Quickstart

Before you begin

1. Select or create a Cloud Platform project.
2. Enable billing for your project.
3. Enable the Google Cloud Pub/Sub API.
4. Set up authentication with a service account so you can access the API from your local workstation.

Installing the client library

npm install @google-cloud/pubsub

Using the client library

// Imports the Google Cloud client library
const {PubSub} = require('@google-cloud/pubsub');

async function quickstart(
  projectId = 'your-project-id', // Your Google Cloud Platform project ID
  topicNameOrId = 'my-topic', // Name for the new topic to create
  subscriptionName = 'my-sub' // Name for the new subscription to create
) {
  // Instantiates a client
  const pubsub = new PubSub({projectId});

  // Creates a new topic
  const [topic] = await pubsub.createTopic(topicNameOrId);
  console.log(`Topic ${topic.name} created.`);

  // Creates a subscription on that new topic
  const [subscription] = await topic.createSubscription(subscriptionName);

  // Receive callbacks for new messages on the subscription
  subscription.on('message', message => {
    console.log('Received message:', message.data.toString());
    process.exit(0);
  });

  // Receive callbacks for errors on the subscription
  subscription.on('error', error => {
    console.error('Received error:', error);
    process.exit(1);
  });

  // Send a message to the topic
  topic.publish(Buffer.from('Test message!'));
}

Running gRPC C++ bindings

For some workflows and environments it might make sense to use the C++ gRPC implementation, instead of the default one (see: #770):

To configure @google-cloud/pubsub to use an alternative grpc transport:

1. npm install grpc, adding grpc as a dependency.

2. instantiate @google-cloud/pubsub with grpc:

   const {PubSub} = require('@google-cloud/pubsub');
   const grpc = require('grpc');
   const pubsub = new PubSub({grpc});
   

Samples

Samples are in the samples/ directory. Each sample's README.md has instructions for running its sample.

Sample	Source Code	Try it
Create an Avro based Schema	source code
Create a Proto based Schema	source code
Create Push Subscription	source code
Create Subscription	source code
Create Subscription With Dead Letter Policy	source code
Create Subscription With Filtering	source code
Create Subscription with ordering enabled	source code
Create Topic	source code
Create Topic With Schema	source code
Delete a previously created schema	source code
Delete Subscription	source code
Delete Topic	source code
Detach Subscription	source code
Get a previously created schema	source code
Get Subscription	source code
Get Subscription Policy	source code
Get Topic Policy	source code
List All Topics	source code
List schemas on a project	source code
List Subscriptions	source code
List Subscriptions On a Topic	source code
Listen For Avro Records	source code
Listen For Errors	source code
Listen For Messages	source code
Listen For Protobuf Messages	source code
Listen For Messages With Custom Attributes	source code
Modify Push Configuration	source code
OpenTelemetry Tracing	source code
Publish Avro Records to a Topic	source code
Publish Batched Messages	source code
Publish Message	source code
Publish Message With Custom Attributes	source code
Publish Ordered Message	source code
Publish Protobuf Messages to a Topic	source code
Publish with flow control	source code
Publish With Retry Settings	source code
Quickstart	source code
Remove Dead Letter Policy	source code
Resume Publish	source code
Set Subscription IAM Policy	source code
Set Topic IAM Policy	source code
Subscribe With Flow Control Settings	source code
Synchronous Pull	source code
Synchronous Pull with delivery attempt.	source code
Synchronous Pull With Lease Management	source code
Test Subscription Permissions	source code
Test Topic Permissions	source code
Update Dead Letter Policy	source code

The Google Cloud Pub/Sub Node.js Client API Reference documentation also contains samples.

Supported Node.js Versions

Our client libraries follow the Node.js release schedule. Libraries are compatible with all current active and maintenance versions of Node.js. If you are using an end-of-life version of Node.js, we recommend that you update as soon as possible to an actively supported LTS version.

Google's client libraries support legacy versions of Node.js runtimes on a best-efforts basis with the following warnings:

• Legacy versions are not tested in continuous integration.
• Some security patches and features cannot be backported.
• Dependencies cannot be kept up-to-date.

Client libraries targeting some end-of-life versions of Node.js are available, and can be installed through npm dist-tags. The dist-tags follow the naming convention legacy-(version). For example, npm install @google-cloud/pubsub@legacy-8 installs client libraries for versions compatible with Node.js 8.

Versioning

This library follows Semantic Versioning.

This library is considered to be stable. The code surface will not change in backwards-incompatible ways unless absolutely necessary (e.g. because of critical security issues) or with an extensive deprecation period. Issues and requests against stable libraries are addressed with the highest priority.

More Information: Google Cloud Platform Launch Stages

Contributing

Contributions welcome! See the Contributing Guide.

Please note that this README.md, the samples/README.md, and a variety of configuration files in this repository (including .nycrc and tsconfig.json) are generated from a central template. To edit one of these files, make an edit to its templates in directory.

License

Apache Version 2.0

See LICENSE

Changelog

2.19.4 (2022-05-05)

Bug Fixes

• deps: update dependency google-gax to v2.30.3 (#1549) (5810331)