How to read all the messages from a azure bus topic from the beginning

Question

If a publisher publishes messages A,B,C I want the consumer to get A,B,C every time the application is launched. Right now A,B,C is shown only the first time and not displayed again since the message is already read. Also other subscribers don't get the message if they join in late.

In kafka we can have below properties in Consumer to get all the messages from the beginning

properties.put(ConsumerConfig.GROUP_ID_CONFIG, UUID.randomUUID().toString()); properties.put(ConsumerConfig.CLIENT_ID_CONFIG, "your_client_id"); properties.put(ConsumerConfig.AUTO_OFFSET_RESET_CONFIG, "earliest"); consumer.seekToBeginning(consumer.assignment())

I'm following the below spring boot code which sends/receives messages from Azure bus...

https://github.com/hildo/azureSamples

There there some configuration or code which I need to change for the consumer to read all the messages from the beginning?

Answer 1

This probably isn't a good use case for Service Bus, but there is a way you may be able to get this to work with Service Bus. It primarily pivots on knowing how many subscribers you are planning to have. Overestimating a bit is fine. Create one subscription per receiver from the beginning. Since they will all need to be there when the message is sent, having the receivers register as they come online won't work for your scenario.

The better solution is probably going to be to make use of a system that is designed to persist messages. How depends on how long you are planning on keeping the messages around. If you want to keep them long term, then something like storage or a database will work fine.

If what you are looking for is essentially Service Bus + replay then I would suggest looking at Event Hub. It's important to note that Event Hub is usually more expensive to use than Service Bus, but from your description of your issue, it's a better fit for what you are trying to achieve. If you need to keep costs down, than using something like Table Storage + an automated process to remove stale messages or querying the table with a date filter will be more work to build and maintain but can do what you need.