Spring Cloud Config with Managing Application Configuration

Source: Spring Cloud Config with Managing Application Configuration

1. What is Spring Cloud Config?

Spring Cloud Config provides server-side and client-side support for externalized configuration in a distributed system. With Spring Cloud Config, you can store your configuration files in a remote repository (e.g., Git, SVN) and access them from multiple applications and environments.

Key Features:
        + Centralized configuration management
        + Dynamic property changes without redeploying applications
        + Support for various backend repositories (Git, SVN, native file system)
        + Encryption and decryption of sensitive properties

2. Setting Up Spring Cloud Config Server

The Spring Cloud Config Server acts as a configuration management service that provides configuration properties to client applications. Let's start by creating a Config Server.

Step 1: Create a New Spring Boot Application

Create a new Spring Boot application with the following dependencies:
         + Spring Cloud Config Server
         + Spring Boot DevTools
         + Spring Web

Maven Configuration (pom.xml):

<dependencies>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-web</artifactId>
    </dependency>
    <dependency>
        <groupId>org.springframework.cloud</groupId>
        <artifactId>spring-cloud-config-server</artifactId>
    </dependency>
</dependencies>

<dependencyManagement>
    <dependencies>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-dependencies</artifactId>
            <version>Hoxton.SR12</version>
            <type>pom</type>
            <scope>import</scope>
        </dependency>
    </dependencies>
</dependencyManagement>

Step 2: Enable the Config Server

In the main application class, annotate with @EnableConfigServer to enable the configuration server.

Main Application Class (ConfigServerApplication.java):

package com.example.configserver;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.config.server.EnableConfigServer;

@SpringBootApplication
@EnableConfigServer
public class ConfigServerApplication {

    public static void main(String[] args) {
        SpringApplication.run(ConfigServerApplication.class, args);
    }
}

Step 3: Configure the Config Server

In the application.yml file, configure the Git repository that the Config Server will use to fetch configuration properties.

application.yml

server:
  port: 8888

spring:
  cloud:
    config:
      server:
        git:
          uri: github.com/your-username/config-repo
          clone-on-start: true

Here, replace github.com/your-username/config-repo with your own Git repository URL containing configuration files.

3. Creating Configuration Files in the Git Repository

In your Git repository, create a new configuration file named application.yml or environment-specific files like application-dev.yml, application-prod.yml.

Example Configuration (application.yml):

server:
  port: 8080

message:
  greeting: "Hello, World!"

4. Setting Up Spring Cloud Config Client

Now, let's create a Spring Boot client application that retrieves its configuration from the Config Server.