12. Gateway new generation gateway

1. General introduction

1.1 What is it? ?

Spring Cloud Gateway The use of Webflux Medium reactor-netty Responsive programming components , The bottom layer uses Netty Communication framework

gateway Official website ：
https://cloud.spring.io/spring-cloud-static/spring-cloud-gateway/2.2.1.RELEASE/reference/html/
zuul github：
https://github.com/Netflix/zuul/wiki

1.2 What can I do? ？

Reverse proxy
authentication
flow control
Fuse
Log monitoring

Where is the gateway in the microservice architecture ？

1.3 With Zuul Why did you come out again gateway

1.3.1.neflix Not very reliable ,zuul2.0 Keep skipping tickets , Delayed release

1.3.2.SpringCloud Gateway Has the following characteristics

1.3.3 SpringCloud Gateway And Zuul The difference between

Zuul1.x Model

1.3.4 Three core concepts

1.3.5Gateway Workflow

Core logic ： Routing and forwarding + Execute the filter chain

2. newly build Module cloud-gateway-gateway9527

2.1 Change pom

 <dependencies>
        <!-- newly added gateway-->
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-gateway</artifactId>
        </dependency>
        <dependency>
            <groupId>com.atguigu.springcloud</groupId>
            <artifactId>cloud-api-commons</artifactId>
            <version>1.0-SNAPSHOT</version>
        </dependency>
        
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-netflix-hystrix</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-devtools</artifactId>
            <scope>runtime</scope>
            <optional>true</optional>
        </dependency>

        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <optional>true</optional>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>

2.2 Change yml

server:
  port: 9527
spring:
  application:
    name: cloud-gateway
  cloud:
    gateway:
      discovery:
        locator:
          enabled: true  # Enable the function of dynamically creating routes from the registry , Routing with microservice name 
      routes:
        - id: payment_routh # The routing ID, There are no fixed rules, but the requirements are unique , Suggested service name 
          #uri: http://localhost:8001 # The routing address of the service after matching 
          uri: lb://cloud-payment-service
          predicates:
            - Path=/payment/get/**   # Assertion , Route with matching path 

        - id: payment_routh2
          #uri: http://localhost:8001 # The routing address of the service after matching 
          uri: lb://cloud-payment-service
          predicates:
            - Path=/payment/lb/**   # Assertion , Route with matching path 

eureka:
  instance:
    hostname: cloud-gateway-service
  client:
    service-url:
      register-with-eureka: true
      fetch-registry: true
      defaultZone: http://eureka7001.com:7001/eureka

Gateway Gateway routing can be configured in two ways ：
a: In profile yml Middle configuration
b: Inject... Into the code RouteLocator Of Bean ( Not recommended )

2.3 Main startup class

@SpringBootApplication
@EnableEurekaClient
public class GateWayMain9527 {
    
    public static void main(String[] args) {
    
            SpringApplication.run( GateWayMain9527.class,args);
        }
}

2.4 test

We don't want to expose 8001 port , Hope that in 8001 Put a layer on the outside 9527

start-up 7001, start-up 8001, start-up 9527 gateway

Before adding a gateway ：http://localhost:8001/payment/get/31
After adding the gateway ：http://localhost:9527/payment/get/31

2.5 Dynamic routing through microservice name

By default Gateway According to the service list of the registry , Create a dynamic route with the micro service name on the registry as the path to forward , So as to realize the function of dynamic routing . There is no need to ip The address is written in the configuration , Just write the service name .

It should be noted that uri The agreement is lb, Means to enable Gateway Load balancing function of .

lb://serviceName yes spring cloud gateway Load balancing created for us automatically in microservices uri

One eureka7001+ Two service providers 8001/8002,http://localhost:9527/payment/lb 8001/8002 Switch between two ports

3.Predicate Use

3.1 What is it? ？

3.2 Predicate Use

1-3 The method to get the expression in ：

public class TimeUtil {
    
    public static void main(String[] args) {
    
        ZonedDateTime zonedDateTime = ZonedDateTime.now();
        System.out.println(zonedDateTime);
    }
}

2022-06-30T23:06:41.697+08:00[Asia/Shanghai]

• Path： The most common way to match the request path , Others are rarely used

summary ：Predicate Just to implement a set of matching rules , Let the request come and find the corresponding Route To deal with . If it doesn't match , You can't access .

4.Filter Use

The self-contained filter is generally not very useful , All are custom global GlobalFilter

Implement these two interfaces ：GlobalFilter ,Ordered

spring Of order in . The smaller the value , The higher the priority , The higher the value, the lower the priority , Priority first .

@Component
@Slf4j
public class MyLogGateWayFilter implements GlobalFilter,Ordered {
    
    @Override
    public Mono<Void> filter(ServerWebExchange exchange, GatewayFilterChain chain) {
    

        log.info("*********come in MyLogGateWayFilter: "+new Date());
        String uname = exchange.getRequest().getQueryParams().getFirst("username");
        if(StringUtils.isEmpty(uname )){
    
            log.info("***** The user is called Null  Illegal users ,(┬＿┬)");
            exchange.getResponse().setStatusCode(HttpStatus.NOT_ACCEPTABLE);// Give someone a response 
            return exchange.getResponse().setComplete();
        }
        return chain.filter(exchange);
    }

    @Override
    public int getOrder() {
    
        return 0;
    }
}

http://localhost:9527/payment/lb?username=z3 Normal visit . Only with username For normal access .