Connecting Spring Boot to Azure App Configuration: Step-by-Step Guide with Code Examples

Introduction:
In today’s cloud-native world, managing application configurations efficiently is crucial, especially when dealing with microservices and distributed environments. Azure App Configuration is a powerful service that centralizes your application settings and feature flags, making it easy to manage configurations dynamically without redeploying your apps.

Spring Boot, being a popular choice for building microservices, can seamlessly integrate with Azure App Configuration, allowing you to dynamically fetch configurations at runtime. This guide walks you through the entire process of integrating Spring Boot with Azure App Configuration, including setting up your environment and testing the integration.

Why Use Azure App Configuration with Spring Boot?
Managing application settings in a distributed system can be challenging. Hardcoding configuration values or storing them locally can lead to issues when scaling services. Azure App Configuration provides:

• Centralized Configuration Management: Keep all your application settings in one place.
• Dynamic Refresh: Update configuration without restarting your applications.
• Versioning and History: Track changes and rollback if needed.
• Feature Flags: Enable or disable features at runtime.

By integrating Azure App Configuration with Spring Boot, you enhance flexibility and streamline configuration management, especially in multi-environment setups.

Step 1: Add Dependencies to pom.xml
Include the necessary dependencies for Azure App Configuration in your Spring Boot project:

<dependencies>
    <dependency>
        <groupId>com.azure.spring</groupId>
        <artifactId>azure-spring-cloud-starter-appconfiguration-config</artifactId>
        <version>5.4.0</version>
    </dependency>
    <dependency>
        <groupId>com.azure.spring</groupId>
        <artifactId>azure-spring-cloud-starter-appconfiguration-config-web</artifactId>
        <version>5.4.0</version>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-web</artifactId>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-actuator</artifactId>
    </dependency>
</dependencies>

Step 2: Configure Azure App Configuration (application.yml)
Configure your application to connect to Azure App Configuration. Replace placeholder values with actual details from your Azure environment.

spring:
  application:
    name: spring-boot-appconfig-demo

  cloud:
    azure:
      appconfiguration:
        stores:
          - name: your-appconfig-name
            endpoint: https://your-appconfig-name.azconfig.io
            connection-string: YOUR_APP_CONFIG_CONNECTION_STRING

• name: The name of your App Configuration instance.
• endpoint: The endpoint URL of your App Configuration.
• connection-string: The connection string from your Azure App Configuration Access Keys.

Step 3: Create a Configuration Class
This class reads configuration values from Azure App Configuration:

package com.example.appconfigdemo;

import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.stereotype.Component;

@Component
@ConfigurationProperties(prefix = "myapp")
public class AppConfigProperties {

    private String greetingMessage;

    public String getGreetingMessage() {
        return greetingMessage;
    }

    public void setGreetingMessage(String greetingMessage) {
        this.greetingMessage = greetingMessage;
    }
}

Example Key-Value in Azure App Configuration:

• Key: myapp.welcome-message
• Value: Hello from Azure App Configuration!

4. Create a REST Controller to Display the Config Value:
This controller will display the welcome message fetched from Azure App Configuration.

package com.example.appconfigdemo;

import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.beans.factory.annotation.Autowired;

@RestController
public class WelcomeController {

    @Autowired
    private AppConfigProperties appConfigProperties;

    @GetMapping("/welcome")
    public String getWelcomeMessage() {
        return appConfigProperties.getWelcomeMessage();
    }
}

5. Run the Spring Boot Application:
Start your application with:

mvn spring-boot:run

Test the Endpoint:
curl http://localhost:8080/welcome

6. Advanced Configuration:
To auto-refresh configuration without restarting the application, include the following:

spring:
  cloud:
    azure:
      appconfiguration:
        watch:
          enabled: true

Conclusion:
By integrating Azure App Configuration with Spring Boot, you centralize your configuration management, making your applications more flexible and scalable. This approach is ideal for microservices or cloud-native applications where configuration values may change frequently.