Package com.azure.messaging.eventhubs

Class EventHubProducerClient

java.lang.Object
com.azure.messaging.eventhubs.EventHubProducerClient
All Implemented Interfaces:
Closeable, AutoCloseable
public class EventHubProducerClient extends Object implements Closeable

A synchronous producer responsible for transmitting EventData to a specific Event Hub, grouped together in batches. Depending on the options specified when creating an EventDataBatch, the events may be automatically routed to an available partition or specific to a partition. More information and specific recommendations for strategies to use when publishing events is in: Distribute events to partitions

Allowing automatic routing of partitions is recommended when:

  • The sending of events needs to be highly available.
  • The event data should be evenly distributed among all available partitions.

If no partition id is specified, the following rules are used for automatically selecting one:

  1. Distribute the events equally amongst all available partitions using a round-robin approach.
  2. If a partition becomes unavailable, the Event Hubs service will automatically detect it and forward the message to another available partition.

The examples shown in this document use a credential object named DefaultAzureCredential for authentication, which is appropriate for most scenarios, including local development and production environments. Additionally, we recommend using managed identity for authentication in production environments. You can find more information on different ways of authenticating and their corresponding credential types in the Azure Identity documentation".

Sample: Construct a EventHubProducerClient

The following code sample demonstrates the creation of the synchronous client EventHubProducerClient. The fullyQualifiedNamespace is the Event Hubs Namespace's host name. It is listed under the "Essentials" panel after navigating to the Event Hubs Namespace via Azure Portal. 

 TokenCredential credential = new DefaultAzureCredentialBuilder().build();

 // "<<fully-qualified-namespace>>" will look similar to "{your-namespace}.servicebus.windows.net"
 // "<<event-hub-name>>" will be the name of the Event Hub instance you created inside the Event Hubs namespace.
 EventHubProducerClient producer = new EventHubClientBuilder()
     .credential("<<fully-qualified-namespace>>", "<<event-hub-name>>",
         credential)
     .buildProducerClient();

Sample: Create a producer and publish events to any partition

The following code sample demonstrates publishing events and allowing the service to distribute the events round-robin between all partitions.

 TokenCredential credential = new DefaultAzureCredentialBuilder().build();

 EventHubProducerClient producer = new EventHubClientBuilder()
     .credential("<<fully-qualified-namespace>>", "<<event-hub-name>>",
         credential)
     .buildProducerClient();

 List<EventData> allEvents = Arrays.asList(new EventData("Foo"), new EventData("Bar"));
 EventDataBatch eventDataBatch = producer.createBatch();

 for (EventData eventData : allEvents) {
     if (!eventDataBatch.tryAdd(eventData)) {
         producer.send(eventDataBatch);
         eventDataBatch = producer.createBatch();

         // Try to add that event that couldn't fit before.
         if (!eventDataBatch.tryAdd(eventData)) {
             throw new IllegalArgumentException("Event is too large for an empty batch. Max size: "
                 + eventDataBatch.getMaxSizeInBytes());
         }
     }
 }

 // send the last batch of remaining events
 if (eventDataBatch.getCount() > 0) {
     producer.send(eventDataBatch);
 }

 // Clients are expected to be long-lived objects.
 // Dispose of the producer to close any underlying resources when we are finished with it.
 producer.close();

Sample: Publish events to partition "0"

The following code sample demonstrates publishing events to a specific partition. In the scenario below, all events are sent to partition "0".

 TokenCredential credential = new DefaultAzureCredentialBuilder().build();

 EventHubProducerClient producer = new EventHubClientBuilder()
     .credential("<<fully-qualified-namespace>>", "<<event-hub-name>>",
         credential)
     .buildProducerClient();

 // Creating a batch with partitionId set will route all events in that batch to partition `0`.
 CreateBatchOptions options = new CreateBatchOptions().setPartitionId("0");
 EventDataBatch batch = producer.createBatch(options);

 // Add events to batch and when you want to send the batch, send it using the producer.
 producer.send(batch);

Sample: Publish events to the same partition, grouped together using partition key

The sample code below uses CreateBatchOptions.setPartitionKey(String) when creating the EventDataBatch. All events added to this batch will be published to the same partition. In general, events with the same partitionKey end up in the same partition.

 List<EventData> events = Arrays.asList(new EventData("sourdough"), new EventData("rye"),
     new EventData("wheat"));

 // Creating a batch with partitionKey set will tell the service to hash the partitionKey and decide which
 // partition to send the events to. Events with the same partitionKey are always routed to the same partition.
 CreateBatchOptions options = new CreateBatchOptions().setPartitionKey("bread");
 EventDataBatch batch = producer.createBatch(options);

 events.forEach(event -> batch.tryAdd(event));
 producer.send(batch);

Sample: Publish events using a size-limited EventDataBatch

The sample code below uses CreateBatchOptions.setMaximumSizeInBytes(int) when creating the EventDataBatch. In the example, it limits the size of the batch to 256 bytes. This is useful for scenarios where there are constraints like network throughput, memory, etc.

 List<EventData> telemetryEvents = Arrays.asList(firstEvent, secondEvent, thirdEvent);

 // Setting `setMaximumSizeInBytes` when creating a batch, limits the size of that batch.
 // In this case, all the batches created with these options are limited to 256 bytes.
 CreateBatchOptions options = new CreateBatchOptions().setMaximumSizeInBytes(256);

 EventDataBatch currentBatch = producer.createBatch(options);

 // For each telemetry event, we try to add it to the current batch.
 // When the batch is full, send it then create another batch to add more events to.
 for (EventData event : telemetryEvents) {
     if (!currentBatch.tryAdd(event)) {
         producer.send(currentBatch);
         currentBatch = producer.createBatch(options);

         // Add the event we couldn't before.
         if (!currentBatch.tryAdd(event)) {
             throw new IllegalArgumentException("Event is too large for an empty batch.");
         }
     }
 }
See Also:

  • Method Details

    • getEventHubName

      public String getEventHubName()
      Gets the Event Hub name this client interacts with.
      Returns:
      The Event Hub name this client interacts with.

    • getFullyQualifiedNamespace

      public String getFullyQualifiedNamespace()
      Gets the fully qualified Event Hubs namespace that the connection is associated with. This is likely similar to {yournamespace}.servicebus.windows.net.
      Returns:
      The fully qualified Event Hubs namespace that the connection is associated with.

    • getEventHubProperties

      public EventHubProperties getEventHubProperties()
      Retrieves information about an Event Hub, including the number of partitions present and their identifiers.
      Returns:
      The set of information for the Event Hub that this client is associated with.

    • getPartitionIds

      public com.azure.core.util.IterableStream<String> getPartitionIds()
      Retrieves the identifiers for the partitions of an Event Hub.
      Returns:
      A Flux of identifiers for the partitions of an Event Hub.

    • getPartitionProperties

      public PartitionProperties getPartitionProperties(String partitionId)
      Retrieves information about a specific partition for an Event Hub, including elements that describe the available events in the partition event stream.
      Parameters:
      partitionId - The unique identifier of a partition associated with the Event Hub.
      Returns:
      The set of information for the requested partition under the Event Hub this client is associated with.
      Throws:
      NullPointerException - if partitionId is null.

    • createBatch

      public EventDataBatch createBatch()
      Creates an EventDataBatch that can fit as many events as the transport allows.
      Returns:
      A new EventDataBatch that can fit as many events as the transport allows.

    • createBatch

      public EventDataBatch createBatch(CreateBatchOptions options)
      Creates an EventDataBatch configured with the options specified.
      Parameters:
      options - A set of options used to configure the EventDataBatch.
      Returns:
      A new EventDataBatch that can fit as many events as the transport allows.
      Throws:
      NullPointerException - if options is null.

    • send

      public void send(Iterable<EventData> events)

      Sends a set of events to the associated Event Hub using a batched approach. If the size of events exceed the maximum size of a single batch, an exception will be triggered and the send will fail. By default, the message size is the max amount allowed on the link.

       List<EventData> events = Arrays.asList(new EventData("maple"), new EventData("aspen"),
     new EventData("oak"));
 producer.send(events);

      For more information regarding the maximum event size allowed, see Azure Event Hubs Quotas and Limits.

      Parameters:
      events - Events to send to the service.
      Throws:
      com.azure.core.amqp.exception.AmqpException - if the size of events exceed the maximum size of a single batch.

    • send

      public void send(Iterable<EventData> events, SendOptions options)

      Sends a set of events to the associated Event Hub using a batched approach. If the size of events exceed the maximum size of a single batch, an exception will be triggered and the send will fail. By default, the message size is the max amount allowed on the link.

       TokenCredential credential = new DefaultAzureCredentialBuilder().build();

 EventHubProducerClient producer = new EventHubClientBuilder()
     .credential("<<fully-qualified-namespace>>", "<<event-hub-name>>",
         credential)
     .buildProducerClient();

 List<EventData> events = Arrays.asList(new EventData("Melbourne"), new EventData("London"),
     new EventData("New York"));

 SendOptions sendOptions = new SendOptions().setPartitionKey("cities");
 producer.send(events, sendOptions);

      For more information regarding the maximum event size allowed, see Azure Event Hubs Quotas and Limits.

      Parameters:
      events - Events to send to the service.
      options - The set of options to consider when sending this batch.
      Throws:
      com.azure.core.amqp.exception.AmqpException - if the size of events exceed the maximum size of a single batch.

    • send

      public void send(EventDataBatch batch)
      Sends the batch to the associated Event Hub.
      Parameters:
      batch - The batch to send to the service.
      Throws:
      NullPointerException - if batch is null.
      See Also:

    • close

      public void close()
      Specified by:
      close in interface AutoCloseable
      Specified by:
      close in interface Closeable

    • getIdentifier

      public String getIdentifier()
      Gets the client identifier.
      Returns:
      The unique identifier string for current client.