[BUG] Async Event Hubs Producer cannot create an Event batch to send data

Describe the bug

I’m following the guide here to create an EventHubProducerAsyncClient – which is different than the EventHubProducerCluent used in the documentation. When I try creating an EventDataBatch to send my data, I get the error:

Looking more into the error it seems that EventHubProducerClient is a wrapper on top of EventHubProducerAsyncClient and it uses the library Mono to convert the Mono object returned from EventHubProducerAsycClient.createBatch() to EventDataBatch. But if I try to createBatch() directly from the Async Producer Client I’m unable to cast it into an EventDataBatch.

Exception or Stack Trace

.../test-event-hub-producer/src/main/java/EventHubProducerMain.java:[18,60] incompatible types: reactor.core.publisher.Mono<com.azure.messaging.eventhubs.EventDataBatch> cannot be converted to com.azure.messaging.eventhubs.EventDataBatch

To Reproduce

• Create an EventHubProducerAsyncClient with the proper connection string and Event Hubs name. More info here.
• Try to create an EventDataBatch to add EventData objects to the batch. Get the error in the screenshot above.

Code Snippet

EventHubProducerAsyncClient eventHubProducer = new EventHubClientBuilder().connectionString(connectionString, eventHubName).buildAsyncProducerClient();
EventDataBatch batch = eventHubProducer.createBatch();

Expected behavior

eventHubProducer.createBatch() should return EventDataBatch type or another compatible type which can be casted into EventDataBatch.

Screenshots

Setup (please complete the following information):

• OS: macOS X
• IDE : IntelliJ
• Version of the Library used: 5.0.2

Additional context

I’m using the following dependency in my pom.xml:

        <dependency>
            <groupId>com.azure</groupId>
            <artifactId>azure-messaging-eventhubs</artifactId>
            <version>5.0.2</version>
        </dependency>

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[srnagar]

Thanks for providing the details. I will look into this issue and let you know.

[Yasara-Y]

Hi @srnagar @aaronkorver , I am experiencing the same error when trying to create an event batch to send data and the error trace is as follows.

Timeout on blocking read for 60000000000 NANOSECONDS java.lang.IllegalStateException: Timeout on blocking read for 60000000000 NANOSECONDS| 
at reactor.core.publisher.BlockingSingleSubscriber.blockingGet(BlockingSingleSubscriber.java:123) ~[reactor-core-3.4.12.jar:3.4.12]| 
at reactor.core.publisher.Mono.block(Mono.java:1731) ~[reactor-core-3.4.12.jar:3.4.12]| 
at com.azure.messaging.eventhubs.EventHubProducerClient.createBatch(EventHubProducerClient.java:128) ~[azure-messaging-eventhubs-5.7.0.jar:?]| 

But some batches are created successfully and published to eventhub. Only some events drop when trying to create a batch. Can you please shed some light on how to resolve this issue?

Created a new issue https://github.com/Azure/azure-sdk-for-java/issues/30256