Getway網關管理ZUUL

1.ZUUL微服務網關

微服務架構體系中，通常一個業務系統會有很多的微服務，比如：OrderService、ProductService、UserService...，為了讓調用更簡單，一般會在這些服務前端再封裝一層，類似下面這樣：

這樣做，當然能跑起來，但是維護量大，以后各個微服務增加了新方法，都需要在網關層手動增加相應的方法封裝，而spring cloud 中的zuul很好的解決了這一問題，示意圖如下：

Zuul做為網關層，自身也是一個微服務，跟其它服務Service-1，Service-2, ... Service-N一樣，都注冊在eureka server上，可以相互發現，zuul能感知到哪些服務在線，同時通過配置路由規則（后面會給出示例），可以將請求自動轉發到指定的后端微服務上，對於一些公用的預處理（比如：權限認證，token合法性校驗，灰度驗證時部分流量引導之類）,可以放在所謂的過濾器(ZuulFilter)里處理，這樣后端服務以后新增了服務，zuul層幾乎不用修改。

2.代碼實現:

代碼的機構圖如下:

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>

啟動類:

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;

//啟動類加上注解@EnableZuulProxy
//它默認加上了@EnableCircuitBreaker和@EnableDiscoveryClient
@SpringBootApplication
@EnableZuulProxy
public class StuZuulApplication {
    public static void main(String[] args) {
        SpringApplication.run(StuZuulApplication.class, args);
    }
}

熔斷器:

這個地方我用的springboot版本比較高,網上大部分是之前的版本的熔斷器的配置,如果產生沖突可以看下是否有哦依賴版本沖突的問題:

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() {
    // 表明是為哪個微服務提供回退，*表示為所有微服務提供回退
    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("服務不可用，請稍后再試。".getBytes());
      }
      @Override
      public HttpHeaders getHeaders() {
        // headers設定
        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 #配置規則 輪詢
  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

上面已經講到注解了@EnableZuulProxy后,它默認加上了@EnableCircuitBreaker和@EnableDiscoveryClient,

另外他是整合了ribbon的,不需要加額外的注解,但是可以配置相關的負載均衡的規則,下面的配置需要額外注意:

zuul:
  routes:
  #配置服務提供者的前綴,替代服務注冊名,訪問的時候就為http://localhost:8040/api-provider/**
    api-a:
      path: /api-provider/**
      service-id: stu-provide
      sensitive-headers:
    #配置消費者的前綴,替代服務注冊名,訪問的時候就為http://localhost:8040/api-consumer/**
    api-b:
      path: /api-consumer/**
      service-id: stu-consumer,stu-consumer-feign-hytrix

啟動后進行訪問,會得到相關提供者的信息.
附上代碼地址:https://github.com/fengcharly/springCloud-ribbon-turbine.git