Class Subscription (2.16.6)

A Subscription object will give you access to your Cloud Pub/Sub subscription.

Subscriptions are sometimes retrieved when using various methods:

Subscription objects may be created directly with:

All Subscription objects are instances of an [EventEmitter](http://nodejs.org/api/events.html). The subscription will pull for messages automatically as long as there is at least one listener assigned for the message event. Available events:

Upon receipt of a message: on(event: 'message', listener: (message: Message) => void): this;

Upon receipt of an error: on(event: 'error', listener: (error: Error) => void): this;

Upon the closing of the subscriber: on(event: 'close', listener: Function): this;

By default Subscription objects allow you to process 100 messages at the same time. You can fine tune this value by adjusting the options.flowControl.maxMessages option.

If your subscription is seeing more re-deliveries than preferable, you might try increasing your options.ackDeadline value or decreasing the options.streamingOptions.maxStreams value.

Subscription objects handle ack management, by automatically extending the ack deadline while the message is being processed, to then issue the ack or nack of such message when the processing is done. **Note:** message redelivery is still possible.

By default each PubSub instance can handle 100 open streams, with default options this translates to less than 20 Subscriptions per PubSub instance. If you wish to create more Subscriptions than that, you can either create multiple PubSub instances or lower the options.streamingOptions.maxStreams value on each Subscription object.

Inheritance

EventEmitter > Subscription

Package

@google-cloud/pubsub!

Constructors

(constructor)(pubsub, name, options)

constructor(pubsub: PubSub, name: string, options?: SubscriptionOptions);

Constructs a new instance of the Subscription class

Parameters

Name	Description
pubsub	`PubSub`
name	`string`
options	`SubscriptionOptions`

Properties

iam

iam: IAM;

Property Value

Type	Description
IAM

isOpen

get isOpen(): boolean;

Indicates if the Subscription is open and receiving messages.

{boolean}

Property Value

Type	Description
boolean

metadata

metadata?: google.pubsub.v1.ISubscription;

Property Value

Type	Description
google.pubsub.v1.ISubscription

name

name: string;

Property Value

Type	Description
string

projectId

get projectId(): string;

{string}

Property Value

Type	Description
string

pubsub

pubsub: PubSub;

Property Value

Type	Description
PubSub

request

request: typeof PubSub.prototype.request;

Property Value

Type	Description
typeof PubSub#request

topic

topic?: Topic | string;

Property Value

Type	Description
Topic \| string

Methods

close()

close(): Promise<void>;

Returns

Type	Description
Promise<void>

close(callback)

close(callback: SubscriptionCloseCallback): void;

Parameter

Name	Description
callback	`SubscriptionCloseCallback`

Returns

Type	Description
void

create(options)

create(options?: CreateSubscriptionOptions): Promise<CreateSubscriptionResponse>;

Parameter

Name	Description
options	`CreateSubscriptionOptions`

Returns

Type	Description
Promise<CreateSubscriptionResponse>

create(callback)

create(callback: CreateSubscriptionCallback): void;

Parameter

Name	Description
callback	`CreateSubscriptionCallback`

Returns

Type	Description
void

create(options, callback)

create(options: CreateSubscriptionOptions, callback: CreateSubscriptionCallback): void;

Parameters

Name	Description
options	`CreateSubscriptionOptions`
callback	`CreateSubscriptionCallback`

Returns

Type	Description
void

createSnapshot(name, gaxOpts)

createSnapshot(name: string, gaxOpts?: CallOptions): Promise<CreateSnapshotResponse>;

Parameters

Name	Description
name	`string`
gaxOpts	`CallOptions`

Returns

Type	Description
Promise<CreateSnapshotResponse>

createSnapshot(name, callback)

createSnapshot(name: string, callback: CreateSnapshotCallback): void;

Parameters

Name	Description
name	`string`
callback	`CreateSnapshotCallback`

Returns

Type	Description
void

createSnapshot(name, gaxOpts, callback)

createSnapshot(name: string, gaxOpts: CallOptions, callback: CreateSnapshotCallback): void;

Parameters

Name	Description
name	`string`
gaxOpts	`CallOptions`
callback	`CreateSnapshotCallback`

Returns

Type	Description
void

delete(gaxOpts)

delete(gaxOpts?: CallOptions): Promise<EmptyResponse>;

Parameter

Name	Description
gaxOpts	`CallOptions`

Returns

Type	Description
Promise<EmptyResponse>

delete(callback)

delete(callback: EmptyCallback): void;

Parameter

Name	Description
callback	`EmptyCallback`

Returns

Type	Description
void

delete(gaxOpts, callback)

delete(gaxOpts: CallOptions, callback: EmptyCallback): void;

Parameters

Name	Description
gaxOpts	`CallOptions`
callback	`EmptyCallback`

Returns

Type	Description
void

detached()

detached(): Promise<DetachedResponse>;

Returns

Type	Description
Promise<DetachedResponse>

detached(callback)

detached(callback: DetachedCallback): void;

Parameter

Name	Description
callback	`DetachedCallback`

Returns

Type	Description
void

exists()

exists(): Promise<ExistsResponse>;

Returns

Type	Description
Promise<ExistsResponse>

exists(callback)

exists(callback: ExistsCallback): void;

Parameter

Name	Description
callback	`ExistsCallback`

Returns

Type	Description
void

formatMetadata_(metadata)

static formatMetadata_(metadata: SubscriptionMetadata): google.pubsub.v1.ISubscription;

Parameter

Name	Description
metadata	`SubscriptionMetadata`

Returns

Type	Description
google.pubsub.v1.ISubscription

formatName_(projectId, name)

static formatName_(projectId: string, name: string): string;

Parameters

Name	Description
projectId	`string`
name	`string`

Returns

Type	Description
string

get(gaxOpts)

get(gaxOpts?: GetSubscriptionOptions): Promise<GetSubscriptionResponse>;

Parameter

Name	Description
gaxOpts	`GetSubscriptionOptions`

Returns

Type	Description
Promise<GetSubscriptionResponse>

get(callback)

get(callback: GetSubscriptionCallback): void;

Parameter

Name	Description
callback	`GetSubscriptionCallback`

Returns

Type	Description
void

get(gaxOpts, callback)

get(gaxOpts: GetSubscriptionOptions, callback: GetSubscriptionCallback): void;

Parameters

Name	Description
gaxOpts	`GetSubscriptionOptions`
callback	`GetSubscriptionCallback`

Returns

Type	Description
void

getMetadata(gaxOpts)

getMetadata(gaxOpts?: CallOptions): Promise<GetSubscriptionMetadataResponse>;

Parameter

Name	Description
gaxOpts	`CallOptions`

Returns

Type	Description
Promise<GetSubscriptionMetadataResponse>

getMetadata(callback)

getMetadata(callback: GetSubscriptionMetadataCallback): void;

Parameter

Name	Description
callback	`GetSubscriptionMetadataCallback`

Returns

Type	Description
void

getMetadata(gaxOpts, callback)

getMetadata(gaxOpts: CallOptions, callback: GetSubscriptionMetadataCallback): void;

Parameters

Name	Description
gaxOpts	`CallOptions`
callback	`GetSubscriptionMetadataCallback`

Returns

Type	Description
void

modifyPushConfig(config, gaxOpts)

modifyPushConfig(config: PushConfig, gaxOpts?: CallOptions): Promise<EmptyResponse>;

Parameters

Name	Description
config	`PushConfig`
gaxOpts	`CallOptions`

Returns

Type	Description
Promise<EmptyResponse>

modifyPushConfig(config, callback)

modifyPushConfig(config: PushConfig, callback: EmptyCallback): void;

Parameters

Name	Description
config	`PushConfig`
callback	`EmptyCallback`

Returns

Type	Description
void

modifyPushConfig(config, gaxOpts, callback)

modifyPushConfig(config: PushConfig, gaxOpts: CallOptions, callback: EmptyCallback): void;

Parameters

Name	Description
config	`PushConfig`
gaxOpts	`CallOptions`
callback	`EmptyCallback`

Returns

Type	Description
void

open()

open(): void;

Opens the Subscription to receive messages. In general this method shouldn't need to be called, unless you wish to receive messages after calling . Alternatively one could just assign a new message event listener which will also re-open the Subscription.

Returns

Type	Description
void

seek(snapshot, gaxOpts)

seek(snapshot: string | Date, gaxOpts?: CallOptions): Promise<SeekResponse>;

Parameters

Name	Description
snapshot	`string \| Date`
gaxOpts	`CallOptions`

Returns

Type	Description
Promise<SeekResponse>

seek(snapshot, callback)

seek(snapshot: string | Date, callback: SeekCallback): void;

Parameters

Name	Description
snapshot	`string \| Date`
callback	`SeekCallback`

Returns

Type	Description
void

seek(snapshot, gaxOpts, callback)

seek(snapshot: string | Date, gaxOpts: CallOptions, callback: SeekCallback): void;

Parameters

Name	Description
snapshot	`string \| Date`
gaxOpts	`CallOptions`
callback	`SeekCallback`

Returns

Type	Description
void

setMetadata(metadata, gaxOpts)

setMetadata(metadata: SubscriptionMetadata, gaxOpts?: CallOptions): Promise<SetSubscriptionMetadataResponse>;

Parameters

Name	Description
metadata	`SubscriptionMetadata`
gaxOpts	`CallOptions`

Returns

Type	Description
Promise<SetSubscriptionMetadataResponse>

setMetadata(metadata, callback)

setMetadata(metadata: SubscriptionMetadata, callback: SetSubscriptionMetadataCallback): void;

Parameters

Name	Description
metadata	`SubscriptionMetadata`
callback	`SetSubscriptionMetadataCallback`

Returns

Type	Description
void

setMetadata(metadata, gaxOpts, callback)

setMetadata(metadata: SubscriptionMetadata, gaxOpts: CallOptions, callback: SetSubscriptionMetadataCallback): void;

Parameters

Name	Description
metadata	`SubscriptionMetadata`
gaxOpts	`CallOptions`
callback	`SetSubscriptionMetadataCallback`

Returns

Type	Description
void

setOptions(options)

setOptions(options: SubscriberOptions): void;

Sets the Subscription options.

Parameter

Name	Description
options	`SubscriberOptions` The options.

Returns

Type	Description
void

snapshot(name)

snapshot(name: string): Snapshot;

Create a Snapshot object. See to create a snapshot.

Parameter

Name	Description
name	`string` The name of the snapshot.

Returns

Type	Description
Snapshot	{Snapshot}