API Gateway

EventStorming Model Preparation

• Open the model in a new tab using the link : Model Link
• If the model doesn't load, click on the avatar icon (person shape) in the upper right, log in with your Github account, and then reload.
• Verify that the model, as needed for the level, is displayed.

Unification of Microservices Endpoints using API Gateway

• Select CODE > ProjectIDE from the menu to load the connected browser IDE.
• Install the http client in the terminal and run Kafka locally with containerization.

pip install httpie
cd infra
docker-compose up

• Run the monolith microservice.

cd monolith
mvn spring-boot:run

• Run the gateway microservice.

cd gateway
mvn spring-boot:run

• Request an order by calling the running monolith service.

  http localhost:8081/orders productId=1 qty=3
  http localhost:8081/orders

• Use the gateway to execute the same URL with a changed port.

 http localhost:8088/orders productId=1 qty=1
 http localhost:8081/orders  # can find the order item here
 http localhost:8088/orders  # can find the order item here also

• Run the inventory microservice.
• Add the following configuration to the spring.cloud.gateway.routes in the application.yaml of the gateway service for routing to the inventory service. (Be careful with indentation)

      - id: inventory
        uri: http://localhost:8082
        predicates:
          - Path=/inventories/** 

• Restart the gateway service.
• Call the service on port 8082 to check and use the gateway to call the service.

http localhost:8082/inventories
http localhost:8088/inventories

Customizing the Gateway

https://www.baeldung.com/spring-cloud-custom-gateway-filters