You can find many articles on the internet about creating a Spring Boot configuration server using either a file system or git repository, but this is not true for a configuration server based on a database. In this article, I am going to discuss reasons to use a database as a configuration server and demonstrate how to create it using Spring Boot.

Storing configurations on a database seems to be a better idea than storing it on either a file system or git. Because it is less trackable, it is less secure. I admit that git has security and tracking options, but they seem to be complicated for a developer. However, tracking a database table is just creating a trigger for updates, and securing a database is not an issue for a developer. Again, changing a value in a database table is just so simple and easy to commit; however, it can be a cumbersome task to make a change in a git repository.

The overall architecture is as follows:

Once you have created your Spring Boot project from the Spring initializer, you need to add the following dependencies to your pom.xml file:

...
  
<!-- CONFIG SERVER -->
<dependency>
	<groupId>org.springframework.cloud</groupId>
	<artifactId>spring-cloud-config-server</artifactId>
</dependency>
<!-- /CONFIG SERVER -->
<!-- JDBC -->
<dependency>
	<groupId>com.github.ulisesbocchio</groupId>
	<artifactId>jasypt-spring-boot-starter</artifactId>
	<version>2.0.0</version>
</dependency>
<dependency>
	<groupId>org.springframework</groupId>
	<artifactId>spring-jdbc</artifactId>
	<exclusions>
		<exclusion>
			<groupId>org.apache.tomcat</groupId>
			<artifactId>tomcat-jdbc</artifactId>
		</exclusion>
	</exclusions>
</dependency>
<dependency>
	<groupId>com.zaxxer</groupId>
	<artifactId>HikariCP</artifactId>
</dependency>
<dependency>
	<!-- Your database driver dependencies here -->
</dependency>
<!-- /JDBC -->

...

Next, you will need to create a table in your database to store the configuration:

CREATE TABLE my_properties 
  ( 
     application VARCHAR(200), 
     profile     VARCHAR(200), 
     label       VARCHAR(200), 
     KEY         VARCHAR(200), 
     value       VARCHAR(200) 
  ) 

Finally, you will need to configure your configuration server with a application.yml file as shown below:

...
spring:
  cloud:
    config:
      server:
        jdbc:
          sql: SELECT KEY, VALUE from  MY_PROPERTIES where APPLICATION=? and PROFILE=? and LABEL=?
          order: 1 
  datasource:
    url: <your db url here>
    driver-class-name: <your databases driver class here>
    username: <your user to database>
    password: 
    hikari:
      maximum-pool-size: 10
      connection-timeout: 5000
  profiles:
    active:
    - jdbc
...

Now, you can test your configuration server with a configuration client.