Building a messaging system

I think that the most suitable way to introduce main Spring Cloud Stream features is through the sample microservices-based system. We will lightly modify an architecture of the system that has been discussed in the previous chapters. Let me provide a short recall of that architecture. Our system is responsible for processing orders. It consists of four independent microservices. The order-service microservice first communicates with product-service in order to collect the details of the selected products, and then with customer-service to retrieve information about the customer and his accounts. Now, the orders sent to order-service will be processed asynchronously. There is still an exposed RESTful HTTP API endpoint for submitting new orders by the clients, but they are not processed by the application. It only saves new orders, sends it to a message broker, and then responds to the client that the order has been approved for processing. The main goal of the...