@google-cloud/pubsub 0.23.0 » Class: Snapshot

Snapshot

class

A Snapshot object will give you access to your Cloud Pub/Sub snapshot.

Snapshots are sometimes retrieved when using various methods:

• PubSub#getSnapshots
• PubSub#getSnapshotsStream
• PubSub#snapshot

Snapshots may be created with:

• Subscription#createSnapshot

You can use snapshots to seek a subscription to a specific point in time.

• Subscription#seek

Constructor

Snapshot

new Snapshot()

Example

//-
// From {@link PubSub#getSnapshots}:
//-
pubsub.getSnapshots((err, snapshots) => {
  // `snapshots` is an array of Snapshot objects.
});

//-
// From {@link PubSub#getSnapshotsStream}:
//-
pubsub.getSnapshotsStream()
  .on('error', console.error)
  .on('data', (snapshot) => {
    // `snapshot` is a Snapshot object.
  });

//-
// From {@link PubSub#snapshot}:
//-
const snapshot = pubsub.snapshot('my-snapshot');
// snapshot is a Snapshot object.

//-
// Create a snapshot with {module:pubsub/subscription#createSnapshot}:
//-
const subscription = pubsub.subscription('my-subscription');

subscription.createSnapshot('my-snapshot', (err, snapshot) => {
  if (!err) {
    // `snapshot` is a Snapshot object.
  }
});

//-
// Seek to your snapshot:
//-
const subscription = pubsub.subscription('my-subscription');

subscription.seek('my-snapshot', (err) => {
  if (err) {
    // Error handling omitted.
  }
});

Methods

create

create(name, callback)

Create a snapshot with the given name.

This is only available if you accessed this object through Subscription#snapshot.

Parameter
name	string Name of the snapshot.
callback	Optional function() The callback function. Values in callback have the following properties: Parameter err error An error from the API call, may be null. Value may be null. snapshot Snapshot The newly created snapshot. apiResponse object The full API response from the service.

Example

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

const callback = (err, snapshot, apiResponse) => {
  if (!err) {
    // The snapshot was created successfully.
  }
};

snapshot.create('my-snapshot', callback);

//-
// If the callback is omitted, we'll return a Promise.
//-
snapshot.create('my-snapshot').then((data) => {
  const snapshot = data[0];
  const apiResponse = data[1];
});

delete

delete(callback)

Delete the snapshot.

Parameter
callback	Optional function() The callback function. Values in callback have the following properties: Parameter err error An error returned while making this request. Value may be null. apiResponse object The full API response from the service.

Example

snapshot.delete((err, apiResponse) => {});

//-
// If the callback is omitted, we'll return a Promise.
//-
snapshot.delete().then((data) => {
  const apiResponse = data[0];
});

seek

seek(callback)

Seeks an existing subscription to the snapshot.

This is only available if you accessed this object through Subscription#snapshot.

Parameter
callback	function() The callback function. Values in callback have the following properties: Parameter err error An error from the API call, may be null. Value may be null. apiResponse object The full API response from the service.

Example

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

snapshot.seek((err, apiResponse) => {});

//-
// If the callback is omitted, we'll return a Promise.
//-
snapshot.seek().then((data) => {
  const apiResponse = data[0];
});