Refactoring to asynchronous communication

In the last chapter, we published messages from the Store Management module to the Shopping Baskets module. We focused on creating the mechanisms between the modules and had only logged to the console when a message arrived. What we started in that chapter was adding new inputs and outputs to the modules:

Figure 7.1 – New message inputs and outputs

We will be adding entirely new asynchronous APIs to the modules to implement the sharing of state via events: event-carried state transfer. Also, it would be an excellent time to reflect on the data each module is sharing with its existing gRPC API. We will be trying to determine what data other modules need to know about to function and where that data originates from.

Store Management state transfer

The Store Management module shares Store and Product information with the other modules. It is the origin of all Store and Product data in our application. However...