Microservices with Clojure

Asynchronous events

Getting data via service endpoints synchronously may become overwhelming for services that maintain a widely used database, like the users database. Therefore, it is recommended for services to maintain a read-only cache for such databases and keep it up to date asynchronously using events, as shown in the following diagram:

For example, instead of looking up the address or order count using service endpoints synchronously, services such as User Service and Orders Service can publish the events of interest on a message queue in order of occurrence. The User Service can then receive the orders event from the Orders Service ...