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.publishMessage({data: 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 BigQuery Subscription | 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 an exactly-once delivery subscription | source code | | | Create Subscription With Filtering | source code | | | Create Subscription with ordering enabled | source code | | | Create Subscription With Retry Policy | 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 with exactly-once delivery | 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 | | | Validate a schema definition | 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