Class SubscriberClient (2.3.0)

Version 2.3.0

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public abstract class SubscriberClient

A PubSub subscriber that is associated with a specific SubscriptionName.

Inheritance

System.Object > SubscriberClient

Inherited Members

System.Object.ToString()

System.Object.GetHashCode()

System.Object.GetType()

System.Object.MemberwiseClone()

Derived Types

SubscriberClientImpl

SubscriberClientImpl

Namespace

Google.Cloud.PubSub.V1

Assembly

Google.Cloud.PubSub.V1.dll

Remarks

To receive messages, the StartAsync(Func<PubsubMessage, CancellationToken, Task<SubscriberClient.Reply>>) 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.

Properties

DefaultAckDeadline

public static TimeSpan DefaultAckDeadline { get; }

The default message ACKnowledgement deadline of 60 seconds.

Property Value
Type	Description
System.TimeSpan

DefaultAckExtensionWindow

public static TimeSpan DefaultAckExtensionWindow { get; }

The default message ACKnowledgement extension window of 15 seconds.

Property Value
Type	Description
System.TimeSpan

DefaultFlowControlSettings

public static FlowControlSettings DefaultFlowControlSettings { get; }

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

Property Value
Type	Description
Google.Api.Gax.FlowControlSettings	Default Google.Api.Gax.FlowControlSettings for SubscriberClient.

DefaultMaxTotalAckExtension

public static TimeSpan DefaultMaxTotalAckExtension { get; }

The default maximum total ACKnowledgement extension of 60 minutes.

Property Value
Type	Description
System.TimeSpan

MaximumAckDeadline

public static TimeSpan MaximumAckDeadline { get; }

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

Property Value
Type	Description
System.TimeSpan

MinimumAckDeadline

public static TimeSpan MinimumAckDeadline { get; }

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

Property Value
Type	Description
System.TimeSpan

MinimumAckExtensionWindow

public static TimeSpan MinimumAckExtensionWindow { get; }

The minimum message ACKnowledgement extension window of 50 milliseconds.

Property Value
Type	Description
System.TimeSpan

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
System.TimeSpan

SubscriptionName

public virtual SubscriptionName SubscriptionName { get; }

The associated SubscriptionName.

Property Value
Type	Description
SubscriptionName

Methods

CreateAsync(SubscriptionName, SubscriberClient.ClientCreationSettings, SubscriberClient.Settings)

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.

Parameters
Name	Description
subscriptionName	SubscriptionName The SubscriptionName to receive messages from.
clientCreationSettings	SubscriberClient.ClientCreationSettings Optional. SubscriberClient.ClientCreationSettings specifying how to create SubscriberClients.
settings	SubscriberClient.Settings Optional. SubscriberClient.Settings for creating a SubscriberClient.

Returns
Type	Description
System.Threading.Tasks.Task<SubscriberClient>	A SubscriberClient instance associated with the specified SubscriptionName.

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

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

Starts receiving messages. The returned System.Threading.Tasks.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	System.Func<PubsubMessage, System.Threading.CancellationToken, System.Threading.Tasks.Task<SubscriberClient.Reply>> 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
System.Threading.Tasks.Task	A System.Threading.Tasks.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 System.Threading.Tasks.Task completes when all handled messages have been ACKnowledged. The returned System.Threading.Tasks.Task faults if there is an unrecoverable error with the underlying service. The returned System.Threading.Tasks.Task cancels if hardStopToken is cancelled.

Parameter
Name	Description
hardStopToken	System.Threading.CancellationToken Cancel this System.Threading.CancellationToken to abort handlers and ACKnowledgement.

Returns
Type	Description
System.Threading.Tasks.Task	A System.Threading.Tasks.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 System.Threading.Tasks.Task completes when all handled messages have been ACKnowledged. The returned System.Threading.Tasks.Task faults if there is an unrecoverable error with the underlying service. The returned System.Threading.Tasks.Task cancels if timeout expires.

Parameter
Name	Description
timeout	System.TimeSpan After this period, abort handling and ACKnowledging messages.

Returns
Type	Description
System.Threading.Tasks.Task	A System.Threading.Tasks.Task that completes when all handled messages have been ACKnowledged; faults on unrecoverable service errors; or cancels if timeout expires.