Use dead letter queues instead of sending to the topic

[arsulegai]

The transaction are processed via the input topic. These transactions are sent to Fabric network for processing. In case of an error, it is further analyzed to see if it is due to the recoverable errors or if it is due to an error reported by Fabric. If the reported error is because of blockchain's operation such as the case of no consensus, these are reported back to the user through the output topic.

The concern however is that the output topic is specifically subscribed to report either the block event or the chaincode event. The error event type is a surprise entry in the topic. Typical place to report such errors is through the dead letter queue.

hlf-connector/src/main/java/hlf/java/rest/client/listener/TransactionConsumer.java

Line 173 in 6860023

eventPublishServiceImpl.publishTransactionFailureEvent(