Class SubscriberClient (2.4.0)

public abstract class SubscriberClient

A PubSub subscriber that is associated with a specific SubscriptionName.

Inheritance

Object > SubscriberClient

Inherited Members

Object.GetHashCode()

Object.GetType()

Object.MemberwiseClone()

Object.ToString()

Derived Types

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
`TimeSpan`

DefaultAckExtensionWindow

public static TimeSpan DefaultAckExtensionWindow { get; }

The default message ACKnowledgement extension window of 15 seconds.

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`

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, SubscriberClient.ClientCreationSettings, SubscriberClient.Settings)

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`	`SubscriberClient.ClientCreationSettings` Optional. SubscriberClient.ClientCreationSettings specifying how to create SubscriberClients.
`settings`	`SubscriberClient.Settings` Optional. SubscriberClient.Settings for creating a SubscriberClient.

Returns
Type	Description
`SubscriberClient`	A SubscriberClient instance associated with the specified SubscriptionName.

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

public static Task<SubscriberClient> CreateAsync(SubscriptionName subscriptionName, SubscriberClient.ClientCreationSettings clientCreationSettings = null, SubscriberClient.Settings settings = null)

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
`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 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

Func<PubsubMessage, CancellationToken, 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
`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.