How do I use transactions to implement atomic operations in RabbitMQ?
RabbitMQ implements AMQP’s TX message class to support atomic operations with clients that request them. If you need only to acknowledge receipt of a message you should get the consumer to send a basic.ack once its done with processing. There’s no need to use tx in this case. However, if you need to both ack a message and publish some other messages as an atomic unit then you should set tx.select on the channel to start a transaction. When processing the received message, you can publish your messages and ack; only when you finally call tx.commit do the actions of the transaction take effect. In this case, if the consumer crashes, the ack and all publications get forgotten: either all of the actions happen or nothing happens. If, at the application level, you realise that due to some external event everything needs to be cancelled then call tx.rollback on the channel.
