[//]: # "This README.md file is auto-generated, all changes to this file will be lost."
[//]: # "To regenerate it, use python -m synthtool."

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][client-docs]
* [Google Cloud Pub/Sub Documentation][product-docs]
* 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][explained].

[explained]: https://cloud.google.com/apis/docs/client-libraries-explained

Table of contents:

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

Quickstart

$3

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

$3

``bash
npm install @google-cloud/pubsub
`

$3

`javascript
// 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.
1. instantiate @google-cloud/pubsub with grpc:

`js
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 | [![Open in Cloud Shell][shell_img]](https://console.cloud.google.com/cloudshell/open?git_repo=https://github.com/googleapis/nodejs-pubsub&page=editor&open_in_editor=samples/createAvroSchema.js,samples/README.md) |
| Create BigQuery Subscription | source code | [![Open in Cloud Shell][shell_img]](https://console.cloud.google.com/cloudshell/open?git_repo=https://github.com/googleapis/nodejs-pubsub&page=editor&open_in_editor=samples/createBigQuerySubscription.js,samples/README.md) |
| Create a Proto based Schema | source code | [![Open in Cloud Shell][shell_img]](https://console.cloud.google.com/cloudshell/open?git_repo=https://github.com/googleapis/nodejs-pubsub&page=editor&open_in_editor=samples/createProtoSchema.js,samples/README.md) |
| Create Push Subscription | source code | [![Open in Cloud Shell][shell_img]](https://console.cloud.google.com/cloudshell/open?git_repo=https://github.com/googleapis/nodejs-pubsub&page=editor&open_in_editor=samples/createPushSubscription.js,samples/README.md) |
| Create Subscription | source code | [![Open in Cloud Shell][shell_img]](https://console.cloud.google.com/cloudshell/open?git_repo=https://github.com/googleapis/nodejs-pubsub&page=editor&open_in_editor=samples/createSubscription.js,samples/README.md) |
| Create Subscription With Dead Letter Policy | source code | [![Open in Cloud Shell][shell_img]](https://console.cloud.google.com/cloudshell/open?git_repo=https://github.com/googleapis/nodejs-pubsub&page=editor&open_in_editor=samples/createSubscriptionWithDeadLetterPolicy.js,samples/README.md) |
| Create an exactly-once delivery subscription | source code | [![Open in Cloud Shell][shell_img]](https://console.cloud.google.com/cloudshell/open?git_repo=https://github.com/googleapis/nodejs-pubsub&page=editor&open_in_editor=samples/createSubscriptionWithExactlyOnceDelivery.js,samples/README.md) |
| Create Subscription With Filtering | source code | [![Open in Cloud Shell][shell_img]](https://console.cloud.google.com/cloudshell/open?git_repo=https://github.com/googleapis/nodejs-pubsub&page=editor&open_in_editor=samples/createSubscriptionWithFiltering.js,samples/README.md) |
| Create Subscription with ordering enabled | source code | [![Open in Cloud Shell][shell_img]](https://console.cloud.google.com/cloudshell/open?git_repo=https://github.com/googleapis/nodejs-pubsub&page=editor&open_in_editor=samples/createSubscriptionWithOrdering.js,samples/README.md) |
| Create Subscription With Retry Policy | source code | [![Open in Cloud Shell][shell_img]](https://console.cloud.google.com/cloudshell/open?git_repo=https://github.com/googleapis/nodejs-pubsub&page=editor&open_in_editor=samples/createSubscriptionWithRetryPolicy.js,samples/README.md) |
| Create Topic | source code | [![Open in Cloud Shell][shell_img]](https://console.cloud.google.com/cloudshell/open?git_repo=https://github.com/googleapis/nodejs-pubsub&page=editor&open_in_editor=samples/createTopic.js,samples/README.md) |
| Create Topic With Schema | source code | [![Open in Cloud Shell][shell_img]](https://console.cloud.google.com/cloudshell/open?git_repo=https://github.com/googleapis/nodejs-pubsub&page=editor&open_in_editor=samples/createTopicWithSchema.js,samples/README.md) |
| Delete a previously created schema | source code | [![Open in Cloud Shell][shell_img]](https://console.cloud.google.com/cloudshell/open?git_repo=https://github.com/googleapis/nodejs-pubsub&page=editor&open_in_editor=samples/deleteSchema.js,samples/README.md) |
| Delete Subscription | source code | [![Open in Cloud Shell][shell_img]](https://console.cloud.google.com/cloudshell/open?git_repo=https://github.com/googleapis/nodejs-pubsub&page=editor&open_in_editor=samples/deleteSubscription.js,samples/README.md) |
| Delete Topic | source code | [![Open in Cloud Shell][shell_img]](https://console.cloud.google.com/cloudshell/open?git_repo=https://github.com/googleapis/nodejs-pubsub&page=editor&open_in_editor=samples/deleteTopic.js,samples/README.md) |
| Detach Subscription | source code | [![Open in Cloud Shell][shell_img]](https://console.cloud.google.com/cloudshell/open?git_repo=https://github.com/googleapis/nodejs-pubsub&page=editor&open_in_editor=samples/detachSubscription.js,samples/README.md) |
| Get a previously created schema | source code | [![Open in Cloud Shell][shell_img]](https://console.cloud.google.com/cloudshell/open?git_repo=https://github.com/googleapis/nodejs-pubsub&page=editor&open_in_editor=samples/getSchema.js,samples/README.md) |
| Get Subscription | source code | [![Open in Cloud Shell][shell_img]](https://console.cloud.google.com/cloudshell/open?git_repo=https://github.com/googleapis/nodejs-pubsub&page=editor&open_in_editor=samples/getSubscription.js,samples/README.md) |
| Get Subscription Policy | source code | [![Open in Cloud Shell][shell_img]](https://console.cloud.google.com/cloudshell/open?git_repo=https://github.com/googleapis/nodejs-pubsub&page=editor&open_in_editor=samples/getSubscriptionPolicy.js,samples/README.md) |
| Get Topic Policy | source code | [![Open in Cloud Shell][shell_img]](https://console.cloud.google.com/cloudshell/open?git_repo=https://github.com/googleapis/nodejs-pubsub&page=editor&open_in_editor=samples/getTopicPolicy.js,samples/README.md) |
| List All Topics | source code | [![Open in Cloud Shell][shell_img]](https://console.cloud.google.com/cloudshell/open?git_repo=https://github.com/googleapis/nodejs-pubsub&page=editor&open_in_editor=samples/listAllTopics.js,samples/README.md) |
| List schemas on a project | source code | [![Open in Cloud Shell][shell_img]](https://console.cloud.google.com/cloudshell/open?git_repo=https://github.com/googleapis/nodejs-pubsub&page=editor&open_in_editor=samples/listSchemas.js,samples/README.md) |
| List Subscriptions | source code | [![Open in Cloud Shell][shell_img]](https://console.cloud.google.com/cloudshell/open?git_repo=https://github.com/googleapis/nodejs-pubsub&page=editor&open_in_editor=samples/listSubscriptions.js,samples/README.md) |
| List Subscriptions On a Topic | source code | [![Open in Cloud Shell][shell_img]](https://console.cloud.google.com/cloudshell/open?git_repo=https://github.com/googleapis/nodejs-pubsub&page=editor&open_in_editor=samples/listTopicSubscriptions.js,samples/README.md) |
| Listen For Avro Records | source code | [![Open in Cloud Shell][shell_img]](https://console.cloud.google.com/cloudshell/open?git_repo=https://github.com/googleapis/nodejs-pubsub&page=editor&open_in_editor=samples/listenForAvroRecords.js,samples/README.md) |
| Listen For Errors | source code | [![Open in Cloud Shell][shell_img]](https://console.cloud.google.com/cloudshell/open?git_repo=https://github.com/googleapis/nodejs-pubsub&page=editor&open_in_editor=samples/listenForErrors.js,samples/README.md) |
| Listen For Messages | source code | [![Open in Cloud Shell][shell_img]](https://console.cloud.google.com/cloudshell/open?git_repo=https://github.com/googleapis/nodejs-pubsub&page=editor&open_in_editor=samples/listenForMessages.js,samples/README.md) |
| Listen with exactly-once delivery | source code | [![Open in Cloud Shell][shell_img]](https://console.cloud.google.com/cloudshell/open?git_repo=https://github.com/googleapis/nodejs-pubsub&page=editor&open_in_editor=samples/listenForMessagesWithExactlyOnceDelivery.js,samples/README.md) |
| Listen For Protobuf Messages | source code | [![Open in Cloud Shell][shell_img]](https://console.cloud.google.com/cloudshell/open?git_repo=https://github.com/googleapis/nodejs-pubsub&page=editor&open_in_editor=samples/listenForProtobufMessages.js,samples/README.md) |
| Listen For Messages With Custom Attributes | source code | [![Open in Cloud Shell][shell_img]](https://console.cloud.google.com/cloudshell/open?git_repo=https://github.com/googleapis/nodejs-pubsub&page=editor&open_in_editor=samples/listenWithCustomAttributes.js,samples/README.md) |
| Modify Push Configuration | source code | [![Open in Cloud Shell][shell_img]](https://console.cloud.google.com/cloudshell/open?git_repo=https://github.com/googleapis/nodejs-pubsub&page=editor&open_in_editor=samples/modifyPushConfig.js,samples/README.md) |
| OpenTelemetry Tracing | source code | [![Open in Cloud Shell][shell_img]](https://console.cloud.google.com/cloudshell/open?git_repo=https://github.com/googleapis/nodejs-pubsub&page=editor&open_in_editor=samples/openTelemetryTracing.js,samples/README.md) |
| Publish Avro Records to a Topic | source code | [![Open in Cloud Shell][shell_img]](https://console.cloud.google.com/cloudshell/open?git_repo=https://github.com/googleapis/nodejs-pubsub&page=editor&open_in_editor=samples/publishAvroRecords.js,samples/README.md) |
| Publish Batched Messages | source code | [![Open in Cloud Shell][shell_img]](https://console.cloud.google.com/cloudshell/open?git_repo=https://github.com/googleapis/nodejs-pubsub&page=editor&open_in_editor=samples/publishBatchedMessages.js,samples/README.md) |
| Publish Message | source code | [![Open in Cloud Shell][shell_img]](https://console.cloud.google.com/cloudshell/open?git_repo=https://github.com/googleapis/nodejs-pubsub&page=editor&open_in_editor=samples/publishMessage.js,samples/README.md) |
| Publish Message With Custom Attributes | source code | [![Open in Cloud Shell][shell_img]](https://console.cloud.google.com/cloudshell/open?git_repo=https://github.com/googleapis/nodejs-pubsub&page=editor&open_in_editor=samples/publishMessageWithCustomAttributes.js,samples/README.md) |
| Publish Ordered Message | source code | [![Open in Cloud Shell][shell_img]](https://console.cloud.google.com/cloudshell/open?git_repo=https://github.com/googleapis/nodejs-pubsub&page=editor&open_in_editor=samples/publishOrderedMessage.js,samples/README.md) |
| Publish Protobuf Messages to a Topic | source code | [![Open in Cloud Shell][shell_img]](https://console.cloud.google.com/cloudshell/open?git_repo=https://github.com/googleapis/nodejs-pubsub&page=editor&open_in_editor=samples/publishProtobufMessages.js,samples/README.md) |
| Publish with flow control | source code | [![Open in Cloud Shell][shell_img]](https://console.cloud.google.com/cloudshell/open?git_repo=https://github.com/googleapis/nodejs-pubsub&page=editor&open_in_editor=samples/publishWithFlowControl.js,samples/README.md) |
| Publish With Retry Settings | source code | [![Open in Cloud Shell][shell_img]](https://console.cloud.google.com/cloudshell/open?git_repo=https://github.com/googleapis/nodejs-pubsub&page=editor&open_in_editor=samples/publishWithRetrySettings.js,samples/README.md) |
| Quickstart | source code | [![Open in Cloud Shell][shell_img]](https://console.cloud.google.com/cloudshell/open?git_repo=https://github.com/googleapis/nodejs-pubsub&page=editor&open_in_editor=samples/quickstart.js,samples/README.md) |
| Remove Dead Letter Policy | source code | [![Open in Cloud Shell][shell_img]](https://console.cloud.google.com/cloudshell/open?git_repo=https://github.com/googleapis/nodejs-pubsub&page=editor&open_in_editor=samples/removeDeadLetterPolicy.js,samples/README.md) |
| Resume Publish | source code | [![Open in Cloud Shell][shell_img]](https://console.cloud.google.com/cloudshell/open?git_repo=https://github.com/googleapis/nodejs-pubsub&page=editor&open_in_editor=samples/resumePublish.js,samples/README.md) |
| Set Subscription IAM Policy | source code | [![Open in Cloud Shell][shell_img]](https://console.cloud.google.com/cloudshell/open?git_repo=https://github.com/googleapis/nodejs-pubsub&page=editor&open_in_editor=samples/setSubscriptionPolicy.js,samples/README.md) |
| Set Topic IAM Policy | source code | [![Open in Cloud Shell][shell_img]](https://console.cloud.google.com/cloudshell/open?git_repo=https://github.com/googleapis/nodejs-pubsub&page=editor&open_in_editor=samples/setTopicPolicy.js,samples/README.md) |
| Subscribe With Flow Control Settings | source code | [![Open in Cloud Shell][shell_img]](https://console.cloud.google.com/cloudshell/open?git_repo=https://github.com/googleapis/nodejs-pubsub&page=editor&open_in_editor=samples/subscribeWithFlowControlSettings.js,samples/README.md) |
| Synchronous Pull | source code | [![Open in Cloud Shell][shell_img]](https://console.cloud.google.com/cloudshell/open?git_repo=https://github.com/googleapis/nodejs-pubsub&page=editor&open_in_editor=samples/synchronousPull.js,samples/README.md) |
| Synchronous Pull with delivery attempt. | source code | [![Open in Cloud Shell][shell_img]](https://console.cloud.google.com/cloudshell/open?git_repo=https://github.com/googleapis/nodejs-pubsub&page=editor&open_in_editor=samples/synchronousPullWithDeliveryAttempts.js,samples/README.md) |
| Synchronous Pull With Lease Management | source code | [![Open in Cloud Shell][shell_img]](https://console.cloud.google.com/cloudshell/open?git_repo=https://github.com/googleapis/nodejs-pubsub&page=editor&open_in_editor=samples/synchronousPullWithLeaseManagement.js,samples/README.md) |
| Test Subscription Permissions | source code | [![Open in Cloud Shell][shell_img]](https://console.cloud.google.com/cloudshell/open?git_repo=https://github.com/googleapis/nodejs-pubsub&page=editor&open_in_editor=samples/testSubscriptionPermissions.js,samples/README.md) |
| Test Topic Permissions | source code | [![Open in Cloud Shell][shell_img]](https://console.cloud.google.com/cloudshell/open?git_repo=https://github.com/googleapis/nodejs-pubsub&page=editor&open_in_editor=samples/testTopicPermissions.js,samples/README.md) |
| Update Dead Letter Policy | source code | [![Open in Cloud Shell][shell_img]](https://console.cloud.google.com/cloudshell/open?git_repo=https://github.com/googleapis/nodejs-pubsub&page=editor&open_in_editor=samples/updateDeadLetterPolicy.js,samples/README.md) |
| Validate a schema definition | source code | [![Open in Cloud Shell][shell_img]](https://console.cloud.google.com/cloudshell/open?git_repo=https://github.com/googleapis/nodejs-pubsub&page=editor&open_in_editor=samples/validateSchema.js,samples/README.md) |

The [Google Cloud Pub/Sub Node.js Client API Reference][client-docs] 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][launch_stages]

[launch_stages]: https://cloud.google.com/terms/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

[client-docs]: https://cloud.google.com/nodejs/docs/reference/pubsub/latest
[product-docs]: https://cloud.google.com/pubsub/docs/
[shell_img]: https://gstatic.com/cloudssh/images/open-btn.png
[projects]: https://console.cloud.google.com/project
[billing]: https://support.google.com/cloud/answer/6293499#enable-billing
[enable_api]: https://console.cloud.google.com/flows/enableapi?apiid=pubsub.googleapis.com
[auth]: https://cloud.google.com/docs/authentication/getting-started