Microservice pattern: Externalized configuration #2679

Description:

The Microservices - Externalized Configuration design pattern is crucial for managing configuration across multiple microservices in a distributed system. This pattern allows for the separation of configuration from the application code, facilitating easier updates and management without redeploying the services. By externalizing configurations, applications can be more flexible and maintainable, adapting to different environments such as development, testing, and production seamlessly.

Main elements of the pattern:

• External Configuration Storage: Store configuration data outside the application, typically in a centralized repository such as a configuration server, database, or environment variables.
• Dynamic Configuration Update: Enable applications to update their configuration dynamically without needing a restart or redeployment.
• Environment-Specific Configurations: Maintain different configurations for various environments (development, testing, production) to ensure appropriate settings are used in each context.
• Security: Secure sensitive configuration data, such as credentials and secrets, to prevent unauthorized access.

References:

1. Microservices Patterns: With examples in Java
2. 12 Factor App: Config
3. Spring Cloud Config Documentation
4. Project Contribution Guidelines
5. Externalized Configuration pattern

Acceptance Criteria:

1. Implement a centralized configuration service that can manage configurations for multiple microservices.
2. Ensure the ability to dynamically update configurations without needing to restart the microservices.
3. Demonstrate the use of environment-specific configurations and secure storage for sensitive data.