Zuul gateway use

Zuul Introduce

Zuul And Spring Cloud Gateway It's about the same , Recommend or use Spring Cloud Gateway, After all, Spring The family's , Higher priority . They are all with Nginx equally , It is mainly used for the reverse proxy of the server ; As long as it is reverse proxy , It takes so long to provide routing 、 monitor 、 elastic 、 Safety and other functions ; Generally speaking, it is a gateway , Because the data flows in and out from this way .

Zuul The core of this is the filter , Through these filters, we can extend a lot of functions , such as ：

1. Dynamic routing
   Dynamically route client requests to different back-end services , Do some logical processing , For example, aggregating data returns from multiple services .
2. Request monitoring
   It can monitor the requests of the whole system , Record detailed request response logs , Can be real-time statistics of the current system access and monitoring status .
3. Authentication
   Authenticate every access request , Refuse illegal request , Protect the back-end services .
4. Pressure test
   Stress testing is a very important job , For example, some e-commerce companies need to simulate more real user concurrency to ensure the stability of the system during major events . adopt Zuul Requests can be forwarded dynamically to the cluster of back-end services , You can also identify test traffic and real traffic , So as to do some special treatment .
5. Grayscale Publishing
   Gray level release can guarantee the stability of the whole system , It can be found in the initial grayscale 、 Adjustment issues , In order to ensure its impact .

Zuul Easy to use

Add dependency configuration , modify pom.xml file

		<dependency>
			<groupId>org.springframework.cloud</groupId>
			<artifactId>spring-cloud-starter-netflix-zuul</artifactId>
		</dependency>
		<dependency>
		    <groupId>org.springframework.cloud</groupId>
		    <artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
		</dependency>

Add configuration information , Modify file application.properties

spring.application.name=zuul-demo
server.port=2103

zuul.routes.test.path=/test/* zuul.routes.test.url=http://192.168.1.244:8081 

Activate zuul, Add startup comment @EnableZuulProxy

@EnableZuulProxy
@SpringBootApplication
public class Application {
    

	public static void main(String[] args) {
    
		SpringApplication.run(Application.class, args);
	}

}

test , Application host rest Service interface

Test the proxy gateway

Integrate Eureka, Forward with the registration service name

Modify file application.properties

spring.application.name=zuul-demo
server.port=2103

#zuul.routes.test.path=/test/* #zuul.routes.test.url=http://192.168.1.244:8081 eureka.client.serviceUrl.defaultZone=http://192.168.1.244:8761/eureka/ 

start-up Eureka

Test gateway

Zuul Routing configuration

The default forwarding rule is API default gateway + The name of the service accessed + Interface URI

Default rule example ：

• API default gateway ：http://localhost:2103.
• User service name ：user-service.
• User login interface ：/user/login.

eg. The above test address we visited ：http://localhost:2103/eureka-provider-app/hello

1. Specify specific service routes

zuul.routes.test.path=/test/* zuul.routes.test.url=http://192.168.1.244:8081 

We will serve /test The first interfaces are forwarded to http://192.168.1.244:8081 On

2. Route prefix
   The destination address after forwarding , Add the prefix , Such as

zuul.prefix=v1.0

Zuul filter

be based on Servlet Implement filters , Implement reference classes com.netflix.zuul.http.ZuulServlet, Method service, The flow is shown in the following figure

The corresponding code

            try {
    
                preRoute();
            } catch (ZuulException e) {
    
                error(e);
                postRoute();
                return;
            }
            try {
    
                route();
            } catch (ZuulException e) {
    
                error(e);
                postRoute();
                return;
            }
            try {
    
                postRoute();
            } catch (ZuulException e) {
    
                error(e);
                return;
            }

For example , Define a token filter （ Casually found an implementation class , Such as DebugFilter, Copy it ）

public class TokenFilter extends ZuulFilter {
    

	@Override
	public boolean shouldFilter() {
    
		return true;
	}

	@Override
	public Object run() throws ZuulException {
    
		RequestContext currentContext = RequestContext.getCurrentContext();
		HttpServletRequest request = currentContext.getRequest();
		String token = request.getHeader("H-TOKEN-X");
		if (StringUtils.isBlank(token) || token.length() < 10) {
    
			currentContext.setSendZuulResponse(false);
			currentContext.getResponse().setContentType("application/json; charset=utf-8");
			currentContext.setResponseBody("invalide token.");
		}
		
		return null;
	}

	@Override
	public String filterType() {
    
		return FilterConstants.PRE_TYPE;
	}

	@Override
	public int filterOrder() {
    
		return 1;
	}

}

Inject objects into spring In the container

@Configuration
public class FilterConfig {
    
	@Bean
	public TokenFilter tokenFilter() {
    
		return new TokenFilter();
	}
}

test ,Token Success stories

test ,Token Failure cases

explain error type , You can handle exceptions , But it will eventually jump to /error uri

In the actual development, refer to the example development , More into understanding can study classes FilterProcessor