Package com.azure.messaging.eventhubs.checkpointstore.blob

Class BlobCheckpointStore

java.lang.Object

com.azure.messaging.eventhubs.checkpointstore.blob.BlobCheckpointStore

All Implemented Interfaces:

CheckpointStore

public class BlobCheckpointStore
extends Object
implements CheckpointStore

Implementation of CheckpointStore that uses Storage Blobs for persisting partition ownership and checkpoint information. EventProcessors can use this implementation to load balance and update checkpoints.

See Also:

EventProcessorClient

Field Summary

Fields

Modifier and Type	Field	Description
static String	EMPTY_STRING	An empty string.

Constructor Summary

Constructors

Constructor	Description
BlobCheckpointStore(com.azure.storage.blob.BlobContainerAsyncClient blobContainerAsyncClient)	Creates an instance of BlobCheckpointStore.

Method Summary

Modifier and Type	Method	Description
Flux<PartitionOwnership>	claimOwnership(List<PartitionOwnership> requestedPartitionOwnerships)	This method is called by the EventProcessorClient to claim ownership of a list of partitions.
Flux<Checkpoint>	listCheckpoints(String fullyQualifiedNamespace, String eventHubName, String consumerGroup)
Flux<PartitionOwnership>	listOwnership(String fullyQualifiedNamespace, String eventHubName, String consumerGroup)	This method is called by the EventProcessorClient to get the list of all existing partition ownership from the Storage Blobs.
Mono<Void>	updateCheckpoint(Checkpoint checkpoint)	Updates the checkpoint in Storage Blobs for a partition.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

EMPTY_STRING

public static final String EMPTY_STRING

An empty string.

See Also:

Constant Field Values

Constructor Detail

BlobCheckpointStore

public BlobCheckpointStore(com.azure.storage.blob.BlobContainerAsyncClient blobContainerAsyncClient)

Creates an instance of BlobCheckpointStore.

Parameters:

blobContainerAsyncClient - The BlobContainerAsyncClient this instance will use to read and update blobs in the storage container.

Method Detail

listOwnership

public Flux<PartitionOwnership> listOwnership(String fullyQualifiedNamespace,
                                              String eventHubName,
                                              String consumerGroup)

This method is called by the EventProcessorClient to get the list of all existing partition ownership from the Storage Blobs. Could return empty results if there are is no existing ownership information.

Specified by:

listOwnership in interface CheckpointStore

Parameters:

eventHubName - The Event Hub name to get ownership information.

consumerGroup - The consumer group name.

Returns:

A flux of partition ownership details of all the partitions that have/had an owner.

listCheckpoints

public Flux<Checkpoint> listCheckpoints(String fullyQualifiedNamespace,
                                        String eventHubName,
                                        String consumerGroup)

Specified by:

listCheckpoints in interface CheckpointStore

claimOwnership

public Flux<PartitionOwnership> claimOwnership(List<PartitionOwnership> requestedPartitionOwnerships)

This method is called by the EventProcessorClient to claim ownership of a list of partitions. This will return the list of partitions that were owned successfully.

Specified by:

claimOwnership in interface CheckpointStore

Parameters:

requestedPartitionOwnerships - List of partition ownerships this instance is requesting to own.

Returns:

A flux of partitions this instance successfully claimed ownership.

updateCheckpoint

public Mono<Void> updateCheckpoint(Checkpoint checkpoint)

Updates the checkpoint in Storage Blobs for a partition.

Specified by:

updateCheckpoint in interface CheckpointStore

Parameters:

checkpoint - Checkpoint information containing sequence number and offset to be stored for this partition.

Returns:

The new ETag on successful update.