Publishing events in transactions with help of Forwarder component (MySQL to Google Pub/Sub)

While working with an event-driven application, you may in some point need to store an application state and publish a message telling the rest of the system about what just happened. As it may look trivial at a first glance, it could become a bit tricky if we consider what can go wrong in case we won't pay enough attention to details.

Solution

This example presents a solution to this problem: saving events in transaction along with persisting application state. It also compares two other approaches which lack transactional publishing therefore expose application to a risk of inconsistency across the system.

Requirements

To run this example you will need Docker and docker-compose installed. See installation guide at https://docs.docker.com/compose/install/

Running

bash

docker-compose up