ADR-0002-expose-quote-endpoint.md

ADR-0002: Expose a REST Endpoint Instead of ApplicationRunner

Status: Accepted Date: 2025-12-13

Context

This application consumes the quote service. We need to decide when and how to call the quote service and return the result.

Options considered:

1. Fetch on startup using ApplicationRunner (original guide pattern)
2. Expose a REST endpoint that fetches on demand
3. Use a scheduled task

Decision

Expose a /quote endpoint that fetches a random quote from the backend on demand.

Option 1 (ApplicationRunner) is rejected for this module in favor of a normal REST endpoint.

This approach is more practical than the original guide's ApplicationRunner pattern:

• The application stays running as a web server
• Users can fetch quotes whenever they want by calling /quote
• Easier to test and demonstrate
• More representative of real-world service-to-service calls

The consumer runs on port 8081 (configured in application.properties) and calls the quote-service on port 8080.

Consequences

Easier:

• Application stays running, can be called repeatedly
• More realistic microservice pattern
• Easier to test with curl or browser
• No timing issues (quote-service just needs to be running)

Harder:

• Differs from the original Spring guide (which uses ApplicationRunner)
• Requires understanding of both provider and consumer as web services

References

• https://spring.io/guides/gs/consuming-rest/
• https://docs.spring.io/spring-boot/reference/io/rest-client.html