Cloud Pub/Sub v1 API - Class SubscriberClient (3.13.0)

public abstract class SubscriberClient : IAsyncDisposable

Reference documentation and code samples for the Cloud Pub/Sub v1 API class SubscriberClient.

A PubSub subscriber that is associated with a specific SubscriptionName.

Inheritance

object > SubscriberClient

Implements

IAsyncDisposable

Derived Types

Namespace

Google.Cloud.PubSub.V1

Assembly

Google.Cloud.PubSub.V1.dll

Remarks

To receive messages, the StartAsync(SubscriptionHandler) method must be called, with a suitable message handler.

The message handler SubscriberClient.Reply states whether to acknowledge the message; if acknowledged then (under normal conditions) it will not be received on this subscription again.

But note that it is always possible to receive duplicate messages. This services guarantees "at least once" delivery, not "only once" delivery.

This class implements the IAsyncDisposable interface. However, it is recommended to create a single SubscriberClient instance, and use it throughout the lifetime of the application. If the SubscriberClient is registered in a dependency injection container, its DisposeAsync method will be called automatically.

Properties

DefaultAckDeadline

public static TimeSpan DefaultAckDeadline { get; }

The default message acknowledgement deadline of 60 seconds.

Property Value
Type Description
TimeSpan

DefaultAckDeadlineForExactlyOnceDelivery

public static TimeSpan DefaultAckDeadlineForExactlyOnceDelivery { get; }

The default message acknowledgement deadline of 60 seconds for exactly-once delivery subscriptions.

Property Value
Type Description
TimeSpan

DefaultAckExtensionWindow

public static TimeSpan DefaultAckExtensionWindow { get; }

The default message acknowledgement extension window of 15 seconds.

Property Value
Type Description
TimeSpan

DefaultDisposeTimeout

public static TimeSpan DefaultDisposeTimeout { get; }

The default DisposeTimeout of 5 seconds for the SubscriberClient.

Property Value
Type Description
TimeSpan

DefaultFlowControlSettings

public static FlowControlSettings DefaultFlowControlSettings { get; }

Default FlowControlSettings for SubscriberClient. Allows 1,000 outstanding messages; and 100Mb outstanding bytes.

Property Value
Type Description
FlowControlSettings

Default FlowControlSettings for SubscriberClient.

DefaultMaxTotalAckExtension

public static TimeSpan DefaultMaxTotalAckExtension { get; }

The default maximum total acknowledgement extension of 60 minutes.

Property Value
Type Description
TimeSpan

MaximumAckDeadline

public static TimeSpan MaximumAckDeadline { get; }

The service-defined maximum message acknowledgement deadline of 10 minutes.

Property Value
Type Description
TimeSpan

MinimumAckDeadline

public static TimeSpan MinimumAckDeadline { get; }

The service-defined minimum message acknowledgement deadline of 10 seconds.

Property Value
Type Description
TimeSpan

MinimumAckExtensionWindow

public static TimeSpan MinimumAckExtensionWindow { get; }

The minimum message acknowledgement extension window of 50 milliseconds.

Property Value
Type Description
TimeSpan

MinimumAckExtensionWindowForExactlyOnceDelivery

[Obsolete("Use DefaultAckDeadlineForExactlyOnceDelivery instead.")]
public static TimeSpan MinimumAckExtensionWindowForExactlyOnceDelivery { get; }

The minimum message acknowledgement extension window of 60 seconds for exactly once delivery subscriptions.

Property Value
Type Description
TimeSpan
Remarks

This property is deprecated. Use DefaultAckDeadlineForExactlyOnceDelivery instead.

MinimumLeaseExtensionDelay

public static TimeSpan MinimumLeaseExtensionDelay { get; }

The enforced 5 second minimum duration between obtaining a lease on a message and when a lease extension can be requested.

Property Value
Type Description
TimeSpan

SubscriptionName

public virtual SubscriptionName SubscriptionName { get; }

The associated SubscriptionName.

Property Value
Type Description
SubscriptionName

Methods

Create(SubscriptionName)

public static SubscriberClient Create(SubscriptionName subscriptionName)

Create a SubscriberClient instance associated with the specified SubscriptionName, using default settings.

Parameter
Name Description
subscriptionName SubscriptionName

The SubscriptionName to receive messages from.
Returns
Type Description
SubscriberClient

A SubscriberClient instance associated with the specified SubscriptionName.

Create(SubscriptionName, ClientCreationSettings, Settings)

[Obsolete("Use SubscriberClient.Create(SubscriptionName) to use the default settings, or SubscriberClientBuilder for customization.")]
public static SubscriberClient Create(SubscriptionName subscriptionName, SubscriberClient.ClientCreationSettings clientCreationSettings = null, SubscriberClient.Settings settings = null)

Create a SubscriberClient instance associated with the specified SubscriptionName. The default settings and clientCreationSettings are suitable for machines with high network bandwidth (e.g. Google Compute Engine instances). If running with more limited network bandwidth, some settings may need changing; especially AckDeadline. By default this method generates a gRPC channel per CPU core; if using a high-core-count machine and using many clients concurrently then this may need reducing; use the setting ClientCount.

Parameters
Name Description
subscriptionName SubscriptionName

The SubscriptionName to receive messages from.
clientCreationSettings SubscriberClientClientCreationSettings

Optional. SubscriberClient.ClientCreationSettings specifying how to create SubscriberClients.
settings SubscriberClientSettings

Optional. SubscriberClient.Settings for creating a SubscriberClient.
Returns
Type Description
SubscriberClient

A SubscriberClient instance associated with the specified SubscriptionName.

CreateAsync(SubscriptionName)

public static Task<SubscriberClient> CreateAsync(SubscriptionName subscriptionName)

Creates a SubscriberClient instance associated with the specified SubscriptionName, using default settings.

Parameter
Name Description
subscriptionName SubscriptionName

The SubscriptionName to receive messages from.
Returns
Type Description
TaskSubscriberClient

A SubscriberClient instance associated with the specified SubscriptionName.

CreateAsync(SubscriptionName, ClientCreationSettings, Settings)

[Obsolete("Use SubscriberClient.Create(SubscriptionName) to use the default settings, or SubscriberClientBuilder for customization.")]
public static Task<SubscriberClient> CreateAsync(SubscriptionName subscriptionName, SubscriberClient.ClientCreationSettings clientCreationSettings = null, SubscriberClient.Settings settings = null)

Create a SubscriberClient instance associated with the specified SubscriptionName. The default settings and clientCreationSettings are suitable for machines with high network bandwidth (e.g. Google Compute Engine instances). If running with more limited network bandwidth, some settings may need changing; especially AckDeadline. By default this method generates a gRPC channel per CPU core; if using a high-core-count machine and using many clients concurrently then this may need reducing; use the setting ClientCount.

Parameters
Name Description
subscriptionName SubscriptionName

The SubscriptionName to receive messages from.
clientCreationSettings SubscriberClientClientCreationSettings

Optional. SubscriberClient.ClientCreationSettings specifying how to create SubscriberClients.
settings SubscriberClientSettings

Optional. SubscriberClient.Settings for creating a SubscriberClient.
Returns
Type Description
TaskSubscriberClient

A SubscriberClient instance associated with the specified SubscriptionName.

DisposeAsync()

public virtual ValueTask DisposeAsync()

Disposes this SubscriberClient asynchronously.

Returns
Type Description
ValueTask
Remarks

This method asynchronously waits for the time interval as specified in the DisposeTimeout for the SubscriberClient to acknowledge the handled messages. If the clean shutdown is not complete after this time, it is aborted; this may leave some handled messages un-acknowledged. The time interval can be customized by setting the DisposeTimeout.

StartAsync(SubscriptionHandler)

public virtual Task StartAsync(SubscriptionHandler handler)

Starts receiving messages. The returned Task completes when either StopAsync(CancellationToken) is called or if an unrecoverable fault occurs. See StopAsync(CancellationToken) for more details. This method cannot be called more than once per SubscriberClient instance.

Parameter
Name Description
handler SubscriptionHandler

The handler that is passed all received messages and acknowledgement results.
Returns
Type Description
Task

A Task that completes when the subscriber is stopped, or if an unrecoverable error occurs.

StartAsync(Func<PubsubMessage, CancellationToken, Task<Reply>>)

public virtual Task StartAsync(Func<PubsubMessage, CancellationToken, Task<SubscriberClient.Reply>> handlerAsync)

Starts receiving messages. The returned Task completes when either StopAsync(CancellationToken) is called or if an unrecoverable fault occurs. See StopAsync(CancellationToken) for more details. This method cannot be called more than once per SubscriberClient instance.

Parameter
Name Description
handlerAsync FuncPubsubMessageCancellationTokenTaskSubscriberClientReply

The handler function that is passed all received messages. This function may be called on multiple threads concurrently. Return Ack from this function to acknowledge this message (implying it won't be received again); or return Nack to Not acknowledge this message (implying it will be received again). If this function throws any Exception, then it behaves as if it returned Nack.
Returns
Type Description
Task

A Task that completes when the subscriber is stopped, or if an unrecoverable error occurs.

StopAsync(CancellationToken)

public virtual Task StopAsync(CancellationToken hardStopToken)

Stop this SubscriberClient. Cancelling hardStopToken aborts the clean stop process, and may leave some handled messages un-acknowledged. The returned Task completes when all handled messages have been acknowledged. The returned Task faults if there is an unrecoverable error with the underlying service. The returned Task cancels if hardStopToken is cancelled.

Parameter
Name Description
hardStopToken CancellationToken

Cancel this CancellationToken to abort handlers and acknowledgement.
Returns
Type Description
Task

A Task that completes when all handled messages have been acknowledged; faults on unrecoverable service errors; or cancels if hardStopToken is cancelled.

StopAsync(TimeSpan)

public virtual Task StopAsync(TimeSpan timeout)

Stop this SubscriberClient. If timeout expires, the clean stop process will be aborted, and may leave some handled messages un-acknowledged. The returned Task completes when all handled messages have been acknowledged. The returned Task faults if there is an unrecoverable error with the underlying service. The returned Task cancels if timeout expires.

Parameter
Name Description
timeout TimeSpan

After this period, abort handling and acknowledging messages.
Returns
Type Description
Task

A Task that completes when all handled messages have been acknowledged; faults on unrecoverable service errors; or cancels if timeout expires.