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Spring Cloud Configuration is a part of the Spring Cloud framework that provides support for externalized configuration in distributed systems. It allows you to centralize your application's configuration in a remote repository and retrieve it dynamically at runtime.

You might have noticed that some of the entries in each application’s application.properties file are common, such as registering with the Eureka server, Email, Security, JPA configurations etc. If we can keep these common entries in one central place and make them accessible by each application, it will make our development easier. Therefore, How can we make a central repository to accommodate all these common entries is the requirement of our discussion in this article. Hence our topic is ‘How To Implement Spring Cloud Config Server In Microservices’.

Generally, we create a space to accommodate our common configuration file in one of the most common repositories, such as Github, Gitlab, Bitbucket etc., provided by the Git vendor. The location of this space is mapped into a central server called Config Server provided by Spring Cloud. Each microservice that will use the common configuration entries will have the Config Server location and act as a Config Client for that Config Server. We will discuss all these in detail in this article. Let’s start discussing ‘How To Implement Spring Cloud Config Server In Microservices’ and its related concepts.

Here are the key components and concepts in Spring Cloud Configuration:

1. Configuration Server:

This is the central component responsible for storing and serving the configuration properties. It exposes an API that allows client applications to fetch their configuration from a variety of backends, such as Git, Subversion, or a local file system.

2. Configuration Client:

The configuration client is a Spring Boot application that fetches its configuration from the Configuration Server. It integrates with Spring's Environment abstraction, allowing the client application to access the configuration properties as if they were defined locally.

3. Configuration Repository:

This is the storage backend where the configuration properties are stored. Spring Cloud Configuration supports various repository types, with Git being the most commonly used. Each application can have its own set of configuration files stored in the repository.

4. Profiles:

Profiles allow you to define different sets of configuration properties for different environments or application variants. For example, you can have separate configurations for development, testing, and production environments. The Configuration Server and clients can fetch the appropriate configuration based on the active profile.

5. Refresh Scope:

Spring Cloud Configuration provides a mechanism for refreshing the configuration of a running application without requiring a restart. By annotating beans with @RefreshScope, you can make them refreshable, allowing changes in the configuration to take effect dynamically.

6. Spring Cloud Config Client Libraries:

Spring Cloud Configuration provides client libraries for different programming languages, making it easier to fetch configuration properties from the Configuration Server in non-Java applications.

By leveraging Spring Cloud Configuration, you can achieve centralized and dynamic configuration management across multiple services or instances of an application in a distributed system. It promotes the separation of configuration from code, allowing you to modify configurations without redeploying or restarting the applications.