Photo credit Gaining complexity in a microservices system certainly isn’t for the faint of heart (though neither is complexity in monoliths!). When there are many services that need to communicate with one another, we might need to coordinate multiple services communicating with multiple other services. We also might code for varying environments such as local, development server, or the cloud. How do services know where to find one another?

Photo credit Our microservices project contains quite a few pieces now. We have two databases, three API services, a user-view service for books, and a service to host our configuration. With so many pieces to manage, it would be nice to have something that orchestrates the individual services into a system, such as Docker Compose. Back in our Level 5 rendition, we did exactly this for our smaller version of the project.

Photo credit In our last blog post, we used Spring Cloud Config to provide database credentials to a microservice application connecting to a cloud-hosted Neo4j database. This post will backport this concept to our existing MongoDB database instance and its related microservices. We will add our MongoDB credentials to the config server, so that it will be the central place for both our Neo4j and MongoDB database access. However, each service only has access to the credentials that it needs to operate, which provides some level of security through "separation of concerns" (versus universal access).