# spring-boot-microservices-project

A small e-commerce system on **Spring Boot 4.1.1** and **Spring Cloud 2025.1.3**, written for the article
[Spring Boot Microservices Project: Gateway, Discovery, Config and 3 Services](https://ankurm.com/spring-boot-microservices-project/).

```
client ──> gateway :8080 ──> product-service   :8081
                         ├─> order-service     :8082 ──> product-service   (read the price)
                         │                          └──> inventory-service (reserve stock, circuit breaker)
                         └─> inventory-service :8083
config-server :8888   serves every service's configuration (and the gateway's routes)
discovery-server :8761  (Eureka) every service registers here and finds the others here
```

| Module | What it is |
|---|---|
| `config-server` | Spring Cloud Config Server, native profile; files in `src/main/resources/config/` |
| `discovery-server` | Eureka server |
| `gateway` | Spring Cloud Gateway Server WebMVC; routes come from the config server (`gateway.yml`) |
| `product-service` | `GET /products`, `GET /products/{id}` |
| `inventory-service` | stock levels, `POST /inventory/{id}/reserve`, a switch to simulate an outage |
| `order-service` | `POST /orders`; calls product-service and inventory-service through the load balancer and a Resilience4j circuit breaker |

## Run it (no Docker needed)

Needs JDK 21+, Maven 3.9+, curl and python3.

```bash
./scripts/run-all.sh        # build, start the six services, run the scenarios, stop everything
./scripts/start.sh          # or: start the services and leave them running
./scripts/demo.sh           # re-run the scenarios (rewrites output/)
./scripts/stop.sh
```

Start order matters: **config server first** (everything else reads its configuration from it), then Eureka, then the rest.

## Docker

`Dockerfile` and `docker-compose.yml` are provided but were **not run**: the sandbox this was written in had no Docker.
Treat them as a starting point, not a tested artifact.

## Captured output

Every file in `output/` is written by `scripts/demo.sh` from real requests. Nothing is typed by hand.

| File | What it shows |
|---|---|
| `01-config-server.txt` | What the config server serves and the value the order service ended up with |
| `02-eureka-registry.txt` | The instances registered in Eureka |
| `03-gateway-requests.txt` | Requests through the gateway: products, stock, orders, and the error cases |
| `04-trace-propagation.txt` | One request, one trace id, in the logs of four services |
| `05-circuit-breaker.txt` | The circuit breaker going CLOSED, OPEN, and back to CLOSED |

## Versions

Spring Boot 4.1.1, Spring Framework 7, Spring Cloud 2025.1.3 (its BOM is built against Boot 4.0.8; it ran here on 4.1.1),
Tomcat 11, Java 21 (OpenJDK 21.0.12). JDK 25 was not available when this was written.