EventHubConsumerClient.ReadEventsAsync Method
Definition
Important
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Overloads
| ReadEventsAsync(CancellationToken) |
Reads events from all partitions of the event hub as an asynchronous enumerable, allowing events to be iterated as they become available on the partition, waiting as necessary should there be no events available. This enumerator may block for an indeterminate amount of time for an |
| ReadEventsAsync(ReadEventOptions, CancellationToken) |
Reads events from all partitions of the event hub as an asynchronous enumerable, allowing events to be iterated as they become available on the partition, waiting as necessary should there be no events available. This enumerator may block for an indeterminate amount of time for an |
| ReadEventsAsync(Boolean, ReadEventOptions, CancellationToken) |
Reads events from all partitions of the event hub as an asynchronous enumerable, allowing events to be iterated as they become available on the partition, waiting as necessary should there be no events available. This enumerator may block for an indeterminate amount of time for an |
ReadEventsAsync(CancellationToken)
- Source:
- EventHubConsumerClient.cs
- Source:
- EventHubConsumerClient.cs
Reads events from all partitions of the event hub as an asynchronous enumerable, allowing events to be iterated as they become available on the partition, waiting as necessary should there be no events available.
This enumerator may block for an indeterminate amount of time for an await if events are not available on the partition, requiring
cancellation via the cancellationToken to be requested in order to return control. It is recommended to set the
MaximumWaitTime for scenarios where a more deterministic maximum waiting period is desired.
public virtual System.Collections.Generic.IAsyncEnumerable<Azure.Messaging.EventHubs.Consumer.PartitionEvent> ReadEventsAsync (System.Threading.CancellationToken cancellationToken = default);abstract member ReadEventsAsync : System.Threading.CancellationToken -> System.Collections.Generic.IAsyncEnumerable<Azure.Messaging.EventHubs.Consumer.PartitionEvent>
override this.ReadEventsAsync : System.Threading.CancellationToken -> System.Collections.Generic.IAsyncEnumerable<Azure.Messaging.EventHubs.Consumer.PartitionEvent>Public Overridable Function ReadEventsAsync (Optional cancellationToken As CancellationToken = Nothing) As IAsyncEnumerable(Of PartitionEvent)Parameters
- cancellationToken
- CancellationToken
An optional CancellationToken instance to signal the request to cancel the operation.
Returns
An IAsyncEnumerable<T> to be used for iterating over events in the partition.
Exceptions
Occurs when an EventHubConsumerClient is unable to read from the Event Hub due to another reader having asserted exclusive ownership. In this case, the EventHubsException.FailureReason will be set to ConsumerDisconnected.
Remarks
This method is not recommended for production use; the EventProcessorClient should be used for reading events from all partitions in a production scenario, as it offers a much more robust experience with higher throughput.
It is important to note that this method does not guarantee fairness amongst the partitions during iteration; each of the partitions compete to publish events to be read by the enumerator. Depending on service communication, there may be a clustering of events per partition and/or there may be a noticeable bias for a given partition or subset of partitions.
Each reader of events is presented with an independent iterator; if there are multiple readers, each receive their own copy of an event to process, rather than competing for them.
See also
Applies to
ReadEventsAsync(ReadEventOptions, CancellationToken)
- Source:
- EventHubConsumerClient.cs
- Source:
- EventHubConsumerClient.cs
Reads events from all partitions of the event hub as an asynchronous enumerable, allowing events to be iterated as they become available on the partition, waiting as necessary should there be no events available.
This enumerator may block for an indeterminate amount of time for an await if events are not available on the partition, requiring
cancellation via the cancellationToken to be requested in order to return control. It is recommended to set the
MaximumWaitTime for scenarios where a more deterministic maximum waiting period is desired.
public virtual System.Collections.Generic.IAsyncEnumerable<Azure.Messaging.EventHubs.Consumer.PartitionEvent> ReadEventsAsync (Azure.Messaging.EventHubs.Consumer.ReadEventOptions readOptions, System.Threading.CancellationToken cancellationToken = default);abstract member ReadEventsAsync : Azure.Messaging.EventHubs.Consumer.ReadEventOptions * System.Threading.CancellationToken -> System.Collections.Generic.IAsyncEnumerable<Azure.Messaging.EventHubs.Consumer.PartitionEvent>
override this.ReadEventsAsync : Azure.Messaging.EventHubs.Consumer.ReadEventOptions * System.Threading.CancellationToken -> System.Collections.Generic.IAsyncEnumerable<Azure.Messaging.EventHubs.Consumer.PartitionEvent>Public Overridable Function ReadEventsAsync (readOptions As ReadEventOptions, Optional cancellationToken As CancellationToken = Nothing) As IAsyncEnumerable(Of PartitionEvent)Parameters
- readOptions
- ReadEventOptions
The set of options to use for configuring read behavior; if not specified the defaults will be used.
- cancellationToken
- CancellationToken
An optional CancellationToken instance to signal the request to cancel the operation.
Returns
An IAsyncEnumerable<T> to be used for iterating over events in the partition.
Exceptions
Occurs when an EventHubConsumerClient is unable to read from the Event Hub due to another reader having asserted exclusive ownership. In this case, the EventHubsException.FailureReason will be set to ConsumerDisconnected.
Remarks
This method is not recommended for production use; the EventProcessorClient should be used for reading events from all partitions in a production scenario, as it offers a much more robust experience with higher throughput.
It is important to note that this method does not guarantee fairness amongst the partitions during iteration; each of the partitions compete to publish events to be read by the enumerator. Depending on service communication, there may be a clustering of events per partition and/or there may be a noticeable bias for a given partition or subset of partitions.
Each reader of events is presented with an independent iterator; if there are multiple readers, each receive their own copy of an event to process, rather than competing for them.
See also
Applies to
ReadEventsAsync(Boolean, ReadEventOptions, CancellationToken)
- Source:
- EventHubConsumerClient.cs
- Source:
- EventHubConsumerClient.cs
Reads events from all partitions of the event hub as an asynchronous enumerable, allowing events to be iterated as they become available on the partition, waiting as necessary should there be no events available.
This enumerator may block for an indeterminate amount of time for an await if events are not available on the partition, requiring
cancellation via the cancellationToken to be requested in order to return control. It is recommended to set the
MaximumWaitTime for scenarios where a more deterministic maximum waiting period is desired.
public virtual System.Collections.Generic.IAsyncEnumerable<Azure.Messaging.EventHubs.Consumer.PartitionEvent> ReadEventsAsync (bool startReadingAtEarliestEvent, Azure.Messaging.EventHubs.Consumer.ReadEventOptions readOptions = default, System.Threading.CancellationToken cancellationToken = default);abstract member ReadEventsAsync : bool * Azure.Messaging.EventHubs.Consumer.ReadEventOptions * System.Threading.CancellationToken -> System.Collections.Generic.IAsyncEnumerable<Azure.Messaging.EventHubs.Consumer.PartitionEvent>
override this.ReadEventsAsync : bool * Azure.Messaging.EventHubs.Consumer.ReadEventOptions * System.Threading.CancellationToken -> System.Collections.Generic.IAsyncEnumerable<Azure.Messaging.EventHubs.Consumer.PartitionEvent>Public Overridable Function ReadEventsAsync (startReadingAtEarliestEvent As Boolean, Optional readOptions As ReadEventOptions = Nothing, Optional cancellationToken As CancellationToken = Nothing) As IAsyncEnumerable(Of PartitionEvent)Parameters
- startReadingAtEarliestEvent
- Boolean
true to begin reading at the first events available in each partition; otherwise, reading will begin at the end of each partition seeing only new events as they are published.
- readOptions
- ReadEventOptions
The set of options to use for configuring read behavior; if not specified the defaults will be used.
- cancellationToken
- CancellationToken
An optional CancellationToken instance to signal the request to cancel the operation.
Returns
An IAsyncEnumerable<T> to be used for iterating over events in the partition.
Exceptions
Occurs when an EventHubConsumerClient is unable to read from the Event Hub due to another reader having asserted exclusive ownership. In this case, the EventHubsException.FailureReason will be set to ConsumerDisconnected.
Remarks
This method is not recommended for production use; the EventProcessorClient should be used for reading events from all partitions in a production scenario, as it offers a much more robust experience with higher throughput.
It is important to note that this method does not guarantee fairness amongst the partitions during iteration; each of the partitions competes to publish events to be read by the enumerator. Depending on service communication, there may be a clustering of events per partition and/or there may be a noticeable bias for a given partition or subset of partitions.
Each reader of events is presented with an independent iterator; if there are multiple readers, each receive their own copy of an event to process, rather than competing for them.
See also
Applies to
Azure SDK for .NET