"Bystander" Pulsar Consumer for logging

Question

How do I create a Pulsar consumer that listens to topic(s), but does not acknowledge the messages, basically only "eavesdropping" the conversation.

Answer 1

The Reader interface could be a good fit for this use case. In the beginning, you need to specify from which message you would like to start reading the topic. There is no need to acknowledge messages. When the reader is stopped there will be no subscription left behind. You can find an example here.

One more option is to use interceptors, but it will work only in case you have access to the consumer code.