PubSub

Import the client library
```
const {PubSub} = require('@google-cloud/pubsub');

```

Create a client that uses <a href="https://cloud.google.com/docs/authentication/production#providing_credentials_to_your_application">Application Default Credentials (ADC)</a>:
```
const pubsub = new PubSub();

```

Create a client with <a href="https://cloud.google.com/docs/authentication/production#obtaining_and_providing_service_account_credentials_manually">explicit credentials</a>:
```
const pubsub = new PubSub({
  projectId: 'your-project-id',
  keyFilename: '/path/to/keyfile.json'
});

```

// Imports the Google Cloud client library
import {PubSub} from '@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!')});
}

Members

isEmulator

isIdResolved

v1

Properties:

See:

• v1.PublisherClient
• v1.SubscriberClient

Methods

Parameters:

Returns:

See:

• Schemas: create API Documentation

• Schema#create

Throws:

• If a schema ID or name is not provided.

  Type

  Error

• If an invalid SchemaType is provided.

  Type

  Error

• If an invalid schema definition is provided.

  Type

  Error

Create a schema.
```
const {PubSub} = require('@google-cloud/pubsub');
const pubsub = new PubSub();

await pubsub.createSchema(
  'messageType',
  SchemaTypes.Avro,
  '{...avro definition...}'
);
```

Returns:

Returns:

Parameters:

Returns:

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

pubsub.getSnapshotsStream()
  .on('error', console.error)
  .on('data', function(snapshot) {
    // snapshot is a Snapshot object.
  })
  .on('end', function() {
    // All snapshots retrieved.
  });

//-
// If you anticipate many results, you can end a stream early to prevent
// unnecessary processing and API requests.
//-
pubsub.getSnapshotsStream()
  .on('data', function(snapshot) {
    this.end();
  });
```

Parameters:

Returns:

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

pubsub.getSubscriptionsStream()
  .on('error', console.error)
  .on('data', function(subscription) {
    // subscription is a Subscription object.
  })
  .on('end', function() {
    // All subscriptions retrieved.
  });

//-
// If you anticipate many results, you can end a stream early to prevent
// unnecessary processing and API requests.
//-
pubsub.getSubscriptionsStream()
  .on('data', function(subscription) {
    this.end();
  });
```

Parameters:

Returns:

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

const topic = pubsub.topic('my-topic');

topic.getSubscriptionsStream()
  .on('error', console.error)
  .on('data', (subscription) => {
    // subscription is a Subscription object.
  })
  .on('end', () => {
    // All subscriptions retrieved.
  });

//-
// If you anticipate many results, you can end a stream early to prevent
// unnecessary processing and API requests.
//-
topic.getSubscriptionsStream()
  .on('data', function(subscription) {
    this.end();
  });
```

Parameters:

Returns:

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

pubsub.getTopicsStream()
  .on('error', console.error)
  .on('data', function(topic) {
    // topic is a Topic object.
  })
  .on('end', function() {
    // All topics retrieved.
  });

//-
// If you anticipate many results, you can end a stream early to prevent
// unnecessary processing and API requests.
//-
pubsub.getTopicsStream()
  .on('data', function(topic) {
    this.end();
  });
```

Parameters:

Returns:

See:

• Schemas: list API Documentation

• More about async iterators

```
for await (const s of pubsub.listSchemas()) {
  const moreInfo = await s.get();
}
```

Parameters:

Returns:

Throws:

If a name is not provided.

Type

Error

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

const schema = pubsub.schema('my-schema');
```

Parameters:

Returns:

Throws:

If a name is not provided.

Type

Error

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

const snapshot = pubsub.snapshot('my-snapshot');
```

Parameters:

Returns:

Throws:

If subscription name is omitted.

Type

Error

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

const subscription = pubsub.subscription('my-subscription');

// Register a listener for `message` events.
subscription.on('message', function(message) {
  // Called every time a message is received.
  // message.id = ID of the message.
  // message.ackId = ID used to acknowledge the message receival.
  // message.data = Contents of the message.
  // message.attributes = Attributes of the message.
  // message.publishTime = Date when Pub/Sub received the message.
});
```

Parameters:

Returns:

Throws:

If a name is not provided.

Type

Error

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

const topic = pubsub.topic('my-topic');
```

Parameters:

Returns:

See:

• Schemas: validateSchema API Documentation

Throws:

if the validation fails.

Type

Error