Introducing Spring Cloud Config & Bus-Refresh

To solve the inefficiency of having to redeploy an entire service just to change a single configuration value in a microservices (MSA) environment, we introduced Spring Cloud Config Server and Bus-Refresh.

Spring Cloud Config Server centrally manages configuration files from a repository such as Git and acts as a conductor that propagates changes to each service in real time. Compared to the existing AWS Parameter Store, it has the advantage of enabling version control and rollback via Git, and structuring complex configuration hierarchies.

The operation process of the built architecture is as follows:

• When a composer (user) pushes a configuration to Git,
• Config Server detects the change and calls the /actuator/busrefresh endpoint.
• This signal is propagated to all microservices via Amazon MQ,
• and each service immediately reflects the new configuration.

When applying configuration, the @RefreshScope annotation must be used to refresh the Bean; however, caution is needed since it cannot be applied in cases where the structure is fixed at compile time, such as DTO class fields in Java/Kotlin.