spring.cloud.gateway

This project try to show how use spring cloud gateway in spring project
and how can use spring cloud gateway features

features of spring cloud gateway

• Able to match routes on any request attribute.
• we can use predicate for route request to any internal services by config file or class config
• use spring cloud discovery service for find another services
• use filter for modify request (header, url, body) and ...
• use ServerWebExchangeUtils.addOriginalRequestUrl() for store original url
• once we've applied the rewrite logic, we must save the modified URL in the GATEWAY_REQUEST_URL_ATTR exchange's attribute in filters
• use Path rewrite for get request and modify route for internal services
• use circuit breaker pattern
• Request Rate Limiting
• use Retry mechanism with Circuit Breaker to communicate with externalService and become dependent on the upstream service.
  The order-module is written as example of Retry and you can see https://reflectoring.io/retry-with-springboot-resilience4j/ for more detail
• use Project Reactor and Spring Boot 2.0

Run debugMode:

1 - add -Dspring.profiles.active=debug at vm option and start project.

Run project container base

1 - use dockerfile and docker-compose command for run app

• creat package:

mvn clean package

• build image

docker compose build

• run image

docker compose up

manual command for build image:

docker build ./gateway-service/ -t gateway-service:latest
docker build ./discovery-service/ -t discovery-service:latest

manual command for Run container:

docker network create -d bridge my-network
docker run -d --name redis -p 6379:6379 --network my-network redis
docker run -d --name discovery-service -p 8761:8761 --network my-network discovery-service
docker run -d --name gateway-service -p 8091:8091 --network gateway-service

Glossary

- Route: The basic building block of the gateway. It is defined by an ID, a destination URI, a collection of predicates, and a collection of filters. A route is matched if the aggregate predicate is true.
- Predicate: This is a Java 8 Function Predicate. The input type is a Spring Framework ServerWebExchange. This lets you match on anything from the HTTP request, such as headers or parameters.
- Filter: These are instances of GatewayFilter that have been constructed with a specific factory. Here, you can modify requests and responses before or after sending the downstream request.