Getway网关管理ZUUL

1.ZUUL微服务网关

微服务架构体系中，通常一个业务系统会有很多的微服务，比如：OrderService、ProductService、UserService...，为了让调用更简单，一般会在这些服务前端再封装一层，类似下面这样：

image.png

这样做，当然能跑起来，但是维护量大，以后各个微服务增加了新方法，都需要在网关层手动增加相应的方法封装，而spring cloud 中的zuul很好的解决了这一问题，示意图如下：

image.png

Zuul做为网关层，自身也是一个微服务，跟其它服务Service-1，Service-2, ... Service-N一样，都注册在eureka server上，可以相互发现，zuul能感知到哪些服务在线，同时通过配置路由规则（后面会给出示例），可以将请求自动转发到指定的后端微服务上，对于一些公用的预处理（比如：权限认证，token合法性校验，灰度验证时部分流量引导之类）,可以放在所谓的过滤器(ZuulFilter)里处理，这样后端服务以后新增了服务，zuul层几乎不用修改。

2.代码实现:

代码的机构图如下:

image.png

pom.xml:

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>com</groupId>
    <artifactId>stu-zuul</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <packaging>jar</packaging>

    <name>stu-zuul</name>
    <description>Demo project for Spring Boot</description>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.0.3.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
        <java.version>1.8</java.version>
        <spring-cloud.version>Finchley.RELEASE</spring-cloud.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </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-ribbon</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-netflix-zuul</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>

        <!-- https://mvnrepository.com/artifact/org.springframework.cloud/spring-cloud-starter-eureka -->
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-eureka</artifactId>
            <version>1.3.1.RELEASE</version>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-actuator</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-feign</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-hystrix</artifactId>
        </dependency>

    </dependencies>

    <dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-dependencies</artifactId>
                <version>${spring-cloud.version}</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
        </dependencies>
    </dependencyManagement>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>
</project>

启动类:

StuZuulApplication:

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.client.discovery.EnableDiscoveryClient;
import org.springframework.cloud.netflix.zuul.EnableZuulProxy;

//启动类加上注解@EnableZuulProxy
//它默认加上了@EnableCircuitBreaker和@EnableDiscoveryClient
@SpringBootApplication
@EnableZuulProxy
public class StuZuulApplication {
    public static void main(String[] args) {
        SpringApplication.run(StuZuulApplication.class, args);
    }
}

熔断器:

这个地方我用的springboot版本比较高,网上大部分是之前的版本的熔断器的配置,如果产生冲突可以看下是否有哦依赖版本冲突的问题:

MyFallbackProvider

import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.nio.charset.Charset;
import com.netflix.hystrix.exception.HystrixTimeoutException;
import org.springframework.cloud.netflix.zuul.filters.route.FallbackProvider;
import org.springframework.http.HttpHeaders;
import org.springframework.http.HttpStatus;
import org.springframework.http.MediaType;
import org.springframework.http.client.ClientHttpResponse;
import org.springframework.stereotype.Component;

@Component
public class MyFallbackProvider implements FallbackProvider {
  @Override
  public String getRoute() {
    // 表明是为哪个微服务提供回退，*表示为所有微服务提供回退
    return "*";
  }

  @Override
  public ClientHttpResponse fallbackResponse(String route, Throwable cause) {
    return null;
  }

  public ClientHttpResponse fallbackResponse(Throwable cause) {
    if (cause instanceof HystrixTimeoutException) {
      return response(HttpStatus.GATEWAY_TIMEOUT);
    } else {
      return this.fallbackResponse();
    }
  }
  public ClientHttpResponse fallbackResponse() {
    return this.response(HttpStatus.INTERNAL_SERVER_ERROR);
  }
  private ClientHttpResponse response(final HttpStatus status) {
    return new ClientHttpResponse() {
      @Override
      public HttpStatus getStatusCode() throws IOException {
        return status;
      }
      @Override
      public int getRawStatusCode() throws IOException {
        return status.value();
      }
      @Override
      public String getStatusText() throws IOException {
        return status.getReasonPhrase();
      }
      @Override
      public void close() {
      }
      @Override
      public InputStream getBody() throws IOException {
        return new ByteArrayInputStream("服务不可用，请稍后再试。".getBytes());
      }
      @Override
      public HttpHeaders getHeaders() {
        // headers设定
        HttpHeaders headers = new HttpHeaders();
        MediaType mt = new MediaType("application", "json", Charset.forName("UTF-8"));
        headers.setContentType(mt);
        return headers;
      }
    };
  }
}

bootstrap.yml:

server:
  port: 8040
spring:
  application:
    name: stu-zuul
eureka:
  client:
    service-url:
      defaultZone: http://user:password123@localhost:8761/eureka
  instance:
      prefer-ip-address: true
      instance-id: ${spring.application.name}:${spring.cloud.client.ipAddress}:${spring.application.instance_id:${server.port}}
      hostname: localhost
      ip-address: localhost
hystrix.command.default.execution.isolation.thread.timeoutInMilliseconds: 60000
ribbon:
  NFLoadBalancerRuleClassName: com.netflix.loadbalancer.RoundRobinRule #配置规则 轮询
  ConnectTimeout: 3000
  ReadTimeout: 60000
zuul:
  routes:
    api-a:
      path: /api-provider/**
      service-id: stu-provide
      sensitive-headers:
    api-b:
      path: /api-consumer/**
      service-id: stu-consumer,stu-consumer-feign-hytrix

上面已经讲到注解了@EnableZuulProxy后,它默认加上了@EnableCircuitBreaker和@EnableDiscoveryClient,

另外他是整合了ribbon的,不需要加额外的注解,但是可以配置相关的负载均衡的规则,下面的配置需要额外注意:

zuul:
  routes:
  #配置服务提供者的前缀,替代服务注册名,访问的时候就为http://localhost:8040/api-provider/**
    api-a:
      path: /api-provider/**
      service-id: stu-provide
      sensitive-headers:
    #配置消费者的前缀,替代服务注册名,访问的时候就为http://localhost:8040/api-consumer/**
    api-b:
      path: /api-consumer/**
      service-id: stu-consumer,stu-consumer-feign-hytrix

启动后进行访问,会得到相关提供者的信息.