A real time microservices supply monitoring project utilizing spring cloud technologies framework. Services can connect/interact with each other or can also connect with external tools as shown in the Architectural layer below.

• Event driven activity such as notifying customers when order has been made was implemented with kafka. The kafka broker was set up using Docker and Spring for Apache kafka.

• Distributed Tracing was implemented with spring-cloud-sleuth and Zipkin for the UI. This helps to track the performance of our app by adding traces and spans id for every api call made to all the services.

• Circuit breaker was implemented using Resilience 4j depency from Spring Cloud circuit breaker framework. This helps to degrade functionality when a method call fails. Since we are implementing a synchronous call to the inventory service, a circuit breaker would ensure clients are routed to a new page when a service fails or takes longer time to respond. More information here.

• Service discovery was implemented with spring cloud discovery Eureka server/client. This helps to persist services on the eureka client side acting as a caching solution when the server is down. This can be seen as an SSG solution for rendering the browser DOM.

• API gateway was implemented with spring cloud gateway to route and filter incoming requests to micro services.

• Order service: Built on mySQL DB. Makes synchronous call to Inventory service to confirm if goods are available and asynchronous call to notification service notifying customers if order was successful.

• Product service: Built on mongoDB. An endpoint to display goods. The frontend would be built on this end point.

• Inventory service: Built on mySQL DB. Takes count of the quantity of goods in stock.

• Notification service: Serveless API to notify cutomers about their orders.