Class Consumer

Consumes an endpoint and invokes a callback delegate when a message is received.

Inheritance

object

Consumer

Consumer<TBroker, TEndpoint, TIdentifier>

Implements

IConsumer

IDisposable

Inherited Members

object.Equals(object)

object.Equals(object, object)

object.GetHashCode()

object.GetType()

object.MemberwiseClone()

object.ReferenceEquals(object, object)

object.ToString()

Namespace: Silverback.Messaging.Broker

Assembly: Silverback.Integration.dll

Syntax

public abstract class Consumer : IConsumer, IDisposable

Constructors

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Consumer(IBroker, IConsumerEndpoint, IBrokerBehaviorsProvider<IConsumerBehavior>, IServiceProvider, ISilverbackLogger<Consumer>)

Initializes a new instance of the Consumer class.

Declaration

protected Consumer(IBroker broker, IConsumerEndpoint endpoint, IBrokerBehaviorsProvider<IConsumerBehavior> behaviorsProvider, IServiceProvider serviceProvider, ISilverbackLogger<Consumer> logger)

Parameters

Type	Name	Description
IBroker	broker	The IBroker that is instantiating the consumer.
IConsumerEndpoint	endpoint	The endpoint to be consumed.
IBrokerBehaviorsProvider<IConsumerBehavior>	behaviorsProvider	The IBrokerBehaviorsProvider<TBehavior>.
IServiceProvider	serviceProvider	The IServiceProvider to be used to resolve the needed services.
ISilverbackLogger<Consumer>	logger	The ISilverbackLogger.

Properties

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Broker

Gets the IBroker that owns this consumer.

Declaration

public IBroker Broker { get; }

Property Value

Type	Description
IBroker

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Endpoint

Gets the IConsumerEndpoint representing the endpoint that is being consumed.

Declaration

public IConsumerEndpoint Endpoint { get; }

Property Value

Type	Description
IConsumerEndpoint

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Id

Gets the InstanceIdentifier uniquely identifying the consumer instance.

Declaration

public InstanceIdentifier Id { get; }

Property Value

Type	Description
InstanceIdentifier

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IsConnected

Gets a value indicating whether this consumer has successfully initialized the connection to the message broker.

Declaration

public bool IsConnected { get; }

Property Value

Type	Description
bool

Remarks

This doesn't necessary mean that it is connected and ready to consume. The underlying library might handle the connection process asynchronously in the background or the protocol might require extra steps (e.g. Kafka might require the partitions to be assigned).

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IsConnecting

Gets a value indicating whether this consumer is initializing the connection to the message broker.

Declaration

public bool IsConnecting { get; }

Property Value

Type	Description
bool

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IsConsuming

Gets a value indicating whether this consumer is connected and consuming (started).

Declaration

public bool IsConsuming { get; protected set; }

Property Value

Type	Description
bool

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IsDisconnecting

Gets a value indicating whether the consumer is being disconnected.

Declaration

public bool IsDisconnecting { get; }

Property Value

Type	Description
bool

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IsStopping

Gets a value indicating whether the consumer is being stopped.

Declaration

protected bool IsStopping { get; }

Property Value

Type	Description
bool

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ServiceProvider

Gets the IServiceProvider to be used to resolve the required services.

Declaration

protected IServiceProvider ServiceProvider { get; }

Property Value

Type	Description
IServiceProvider

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StatusInfo

Gets the IConsumerStatusInfo containing the status details and basic statistics of this consumer.

Declaration

public IConsumerStatusInfo StatusInfo { get; }

Property Value

Type	Description
IConsumerStatusInfo

Methods

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CommitAsync(IBrokerMessageIdentifier)

Confirms that the specified message has been successfully processed. The acknowledgement will be sent to the message broker and the message will never be consumed again (by the same logical consumer / consumer group).

Declaration

public Task CommitAsync(IBrokerMessageIdentifier brokerMessageIdentifier)

Parameters

Type	Name	Description
IBrokerMessageIdentifier	brokerMessageIdentifier	The identifier of the message to be committed.

Returns

Type	Description
Task	A Task representing the asynchronous operation.

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CommitAsync(IReadOnlyCollection<IBrokerMessageIdentifier>)

Confirms that the specified messages have been successfully processed. The acknowledgement will be sent to the message broker and the message will never be consumed again (by the same logical consumer / consumer group).

Declaration

public Task CommitAsync(IReadOnlyCollection<IBrokerMessageIdentifier> brokerMessageIdentifiers)

Parameters

Type	Name	Description
IReadOnlyCollection<IBrokerMessageIdentifier>	brokerMessageIdentifiers	The identifiers of to message be committed.

Returns

Type	Description
Task	A Task representing the asynchronous operation.

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CommitCoreAsync(IReadOnlyCollection<IBrokerMessageIdentifier>)

Commits the specified messages sending the acknowledgement to the message broker.

Declaration

protected abstract Task CommitCoreAsync(IReadOnlyCollection<IBrokerMessageIdentifier> brokerMessageIdentifiers)

Parameters

Type	Name	Description
IReadOnlyCollection<IBrokerMessageIdentifier>	brokerMessageIdentifiers	The identifiers of to message be committed.

Returns

Type	Description
Task	A Task representing the asynchronous operation.

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ConnectAsync()

Connects and starts consuming.

Declaration

public Task ConnectAsync()

Returns

Type	Description
Task	A Task representing the asynchronous operation.

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ConnectCoreAsync()

Connects to the message broker.

Declaration

protected abstract Task ConnectCoreAsync()

Returns

Type	Description
Task	A Task representing the asynchronous operation.

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DisconnectAsync()

Disconnects and stops consuming.

Declaration

public Task DisconnectAsync()

Returns

Type	Description
Task	A Task representing the asynchronous operation.

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DisconnectCoreAsync()

Disconnects from the message broker.

Declaration

protected abstract Task DisconnectCoreAsync()

Returns

Type	Description
Task	A Task representing the asynchronous operation.

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Dispose()

Performs application-defined tasks associated with freeing, releasing, or resetting unmanaged resources.

Declaration

public void Dispose()

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Dispose(bool)

Performs application-defined tasks associated with freeing, releasing, or resetting unmanaged resources.

Declaration

protected virtual void Dispose(bool disposing)

Parameters

Type	Name	Description
bool	disposing	A value indicating whether the method has been called by the `Dispose` method and not from the finalizer.

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GetCurrentSequenceStores()

Gets the ISequenceStore instances used by this consumer. Some brokers will require multiple stores (e.g. the KafkaConsumer will create a store per each assigned partition).

Declaration

public abstract IReadOnlyList<ISequenceStore> GetCurrentSequenceStores()

Returns

Type	Description
IReadOnlyList<ISequenceStore>	The list of ISequenceStore.

Remarks

Used only for testing and maintained to preserve backward compatibility.

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HandleMessageAsync(byte[]?, IReadOnlyCollection<MessageHeader>, string, IBrokerMessageIdentifier, ISequenceStore)

Handles the consumed message invoking each IConsumerBehavior in the pipeline.

Declaration

protected virtual Task HandleMessageAsync(byte[]? message, IReadOnlyCollection<MessageHeader> headers, string sourceEndpointName, IBrokerMessageIdentifier brokerMessageIdentifier, ISequenceStore sequenceStore)

Parameters

Type	Name	Description
byte[]	message	The body of the consumed message.
IReadOnlyCollection<MessageHeader>	headers	The headers of the consumed message.
string	sourceEndpointName	The name of the actual endpoint (topic) where the message has been delivered.
IBrokerMessageIdentifier	brokerMessageIdentifier	The identifier of the consumed message.
ISequenceStore	sequenceStore	The ISequenceStore to be used.

Returns

Type	Description
Task	A Task representing the asynchronous operation.

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IncrementFailedAttempts(IRawInboundEnvelope)

Increments the stored failed attempts count for the specified envelope.

Declaration

public int IncrementFailedAttempts(IRawInboundEnvelope envelope)

Parameters

Type	Name	Description
IRawInboundEnvelope	envelope	The envelope.

Returns

Type	Description
int	The current failed attempts count after the increment.

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RevertReadyStatus()

Called when the connection is lost to transitions the consumer back to Connected.

Declaration

protected void RevertReadyStatus()

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RollbackAsync(IBrokerMessageIdentifier)

Notifies that an error occured while processing the specified message. If necessary the information will be sent to the message broker to ensure that the message will be consumed again.

Declaration

public Task RollbackAsync(IBrokerMessageIdentifier brokerMessageIdentifier)

Parameters

Type	Name	Description
IBrokerMessageIdentifier	brokerMessageIdentifier	The identifier of the message to be rolled back.

Returns

Type	Description
Task	A Task representing the asynchronous operation.

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RollbackAsync(IReadOnlyCollection<IBrokerMessageIdentifier>)

Notifies that an error occured while processing the specified messages. If necessary the information will be sent to the message broker to ensure that the message will be re-processed.

Declaration

public Task RollbackAsync(IReadOnlyCollection<IBrokerMessageIdentifier> brokerMessageIdentifiers)

Parameters

Type	Name	Description
IReadOnlyCollection<IBrokerMessageIdentifier>	brokerMessageIdentifiers	The identifiers of to message be rolled back.

Returns

Type	Description
Task	A Task representing the asynchronous operation.

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RollbackCoreAsync(IReadOnlyCollection<IBrokerMessageIdentifier>)

If necessary notifies the message broker that the specified messages couldn't be processed successfully, to ensure that they will be consumed again.

Declaration

protected abstract Task RollbackCoreAsync(IReadOnlyCollection<IBrokerMessageIdentifier> brokerMessageIdentifiers)

Parameters

Type	Name	Description
IReadOnlyCollection<IBrokerMessageIdentifier>	brokerMessageIdentifiers	The identifiers of to message be rolled back.

Returns

Type	Description
Task	A Task representing the asynchronous operation.

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SetReadyStatus()

Called when fully connected to transitions the consumer to Ready.

Declaration

protected void SetReadyStatus()

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StartAsync()

Starts consuming. Used after StopAsync() has been called to resume consuming.

Declaration

public Task StartAsync()

Returns

Type	Description
Task	A Task representing the asynchronous operation.

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StartCoreAsync()

Starts consuming. Called to resume consuming after StopAsync() has been called.

Declaration

protected abstract Task StartCoreAsync()

Returns

Type	Description
Task	A Task representing the asynchronous operation.

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StopAsync()

Stops the consumer without disconnecting. Can be used to pause and resume consuming.

Declaration

public Task StopAsync()

Returns

Type	Description
Task	A Task representing the asynchronous operation. This Task will complete as soon as the stopping signal has been sent.

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StopCoreAsync()

Stops consuming while staying connected to the message broker.

Declaration

protected abstract Task StopCoreAsync()

Returns

Type	Description
Task	A Task representing the asynchronous operation.

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TriggerReconnectAsync()

Disconnects and stops consuming.

Declaration

public Task TriggerReconnectAsync()

Returns

Type	Description
Task	A Task representing the asynchronous operation.

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WaitUntilConsumingStoppedCoreAsync()

Waits until the consuming is stopped.

Declaration

protected abstract Task WaitUntilConsumingStoppedCoreAsync()

Returns

Type	Description
Task	A Task representing the asynchronous operation.

Implements

IConsumer

IDisposable