Summary

In this chapter, we discussed the boundary patterns of reactive, cloud-native systems. Although we focus on asynchronous, event-driven inter-component communication, we ultimately need to implement synchronous communication at the boundaries where the system interacts with humans and external systems. The API Gateway pattern provides a secure and scalable foundation for synchronous communication. With the CQRS pattern, we leverage materialized views to decouple upstream dependencies in order to make the synchronous communication responsive, resilient, and elastic. The offline-first database pattern allows some synchronous interactions to operate locally by storing event and materialized view data in local storage and synchronizing with the cloud to increase the availability of the system from the user's perspective. The BFF is a higher-order pattern that pulls all...