SpringCloud之Zuul

【前面的話】書接上文，前面已經講過了SpringCloud的註冊中心Eureka、Ribbon和Feign等等，若是有不清楚的也能夠去看看個人微服務系列文章。這篇文章我要說的是微服務中的網關。

---

壹、Zuul的簡介

Zuul的主要功能是路由轉發和過濾器。路由功能是微服務的一部分，好比／api/user轉發到到user服務，/api/shop轉發到到shop服務。zuul默認和Ribbon結合實現了負載均衡的功能。

zuul有如下功能：

Authentication
Insights
Stress Testing
Canary Testing
Dynamic Routing
Service Migration
Load Shedding
Security
Static Response handling
Active/Active traffic management

貳、準備工做

新建一個feign子工程lovin-cloud-zuul，用於後面的操做。下面是主要的pom依賴:

<parent>
        <artifactId>lovincloud</artifactId>
        <groupId>com.eelve.lovincloud</groupId>
        <version>1.0-SNAPSHOT</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>

    <artifactId>lovin-cloud-zuul</artifactId>
    <packaging>jar</packaging>
    <name>lovincloudzuul</name>
    <version>0.0.1</version>
    <description>zuul</description>

    <dependencies>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-security</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-zuul</artifactId>
            <version>1.4.7.RELEASE</version>
        </dependency>
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <optional>true</optional>
        </dependency>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-config</artifactId>
            <version>2.1.3.RELEASE</version>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-actuator</artifactId>
        </dependency>
    </dependencies>

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

• 這裏爲了安全，我這裏仍是添加spring-boot-starter-security，同時配置路由規則發送/api-ribbon/打頭開始的服務轉發到lovinribbonclient而發送/api-feign/打頭的服務轉發到lovinfeignclient，能夠看出這裏是配置相應的路由規則。

server:
  port: 8882   # 服務端口號
spring:
  application:
    name: lovincloudzuul     # 服務名稱
  security:
    basic:
      enabled: true
    user:
      name: lovin
      password: ${REGISTRY_SERVER_PASSWORD:lovin}
zuul:
  routes:
    api-ribbon:
      path: /api-ribbon/**
      serviceId: lovinribbonclient
    api-feign:
      path: /api-feign/**
      serviceId: lovinfeignclient
eureka:
  client:
    serviceUrl:
      defaultZone: http://lovin:lovin@localhost:8881/eureka/   # 註冊到的eureka服務地址
  instance:
    leaseRenewalIntervalInSeconds: 10
    health-check-url-path: /actuator/health
    metadata-map:
      user.name: lovin
      user.password: lovin

• 配置spring-boot-starter-security，這裏爲了方便我這裏放開全部請求

package com.eelve.lovin.config;

import org.springframework.context.annotation.Configuration;
import org.springframework.security.config.annotation.web.builders.HttpSecurity;
import org.springframework.security.config.annotation.web.configuration.WebSecurityConfigurerAdapter;

/**
 * @ClassName WebSecurityConfig
 * @Description TDO
 * @Author zhao.zhilue
 * @Date 2019/8/18 12:17
 * @Version 1.0
 **/
@Configuration
public class WebSecurityConfig extends WebSecurityConfigurerAdapter {

    @Override
    protected void configure(HttpSecurity http) throws Exception {
        http.authorizeRequests().anyRequest().permitAll()
                .and().csrf().disable();
    }
}

• 在主類上添加@EnableZuulProxy ，固然也須要註冊到註冊中心：

package com.eelve.lovin;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.netflix.eureka.EnableEurekaClient;
import org.springframework.cloud.netflix.zuul.EnableZuulProxy;

/**
 * @ClassName LovinEurekaClientApplication
 * @Description TDO
 * @Author zhao.zhilue
 * @Date 2019/8/15 16:37
 * @Version 1.0
 **/
@EnableZuulProxy
@EnableEurekaClient
@SpringBootApplication
public class LovinCloudZuulApplication {
    public static void main(String[] args) {
        SpringApplication.run(LovinCloudZuulApplication.class,args);
    }
}

• 這裏爲了方便測試，這裏配置相應的過濾規則：

package com.eelve.lovin.filter;

import com.netflix.zuul.ZuulFilter;
import com.netflix.zuul.context.RequestContext;
import com.netflix.zuul.exception.ZuulException;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.cloud.context.config.annotation.RefreshScope;
import org.springframework.stereotype.Component;

import javax.servlet.http.HttpServletRequest;

/**
 * @ClassName MyFilter
 * @Description TDO
 * @Author zhao.zhilue
 * @Date 2019/8/18 12:44
 * @Version 1.0
 **/
@Component
@RefreshScope // 使用該註解的類，會在接到SpringCloud配置中心配置刷新的時候，自動將新的配置更新到該類對應的字段中。
@Slf4j
public class MyFilter extends ZuulFilter {

    @Override
    public String filterType() {
        return "pre";
    }

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

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

    @Override
    public Object run() throws ZuulException {
        RequestContext ctx = RequestContext.getCurrentContext();
        HttpServletRequest request = ctx.getRequest();
        log.info(String.format("%s >>> %s", request.getMethod(), request.getRequestURL().toString()));
        Object accessToken = request.getParameter("token");
        if(accessToken == null) {
            log.warn("token is empty");
            ctx.setSendZuulResponse(false);
            ctx.setResponseStatusCode(401);
            try {
                ctx.getResponse().getWriter().write("token is empty");
            }catch (Exception e){}

            return null;
        }else if(!accessToken.equals("lovin")){
            log.warn("token is not correct");
            ctx.setSendZuulResponse(false);
            ctx.setResponseStatusCode(403);
            try {
                ctx.getResponse().getWriter().write("token is not correct");
            }catch (Exception e){}

            return null;
        }
        log.info("ok");
        return null;
    }
}

filterType：返回一個字符串表明過濾器的類型，在zuul中定義了四種不一樣生命週期的過濾器類型，具體以下：
        pre：路由以前
        routing：路由之時
        post： 路由以後
        error：發送錯誤調用
    filterOrder：過濾的順序
    shouldFilter：這裏能夠寫邏輯判斷，是否要過濾，本文true,永遠過濾。
    run：過濾器的具體邏輯。可用很複雜，包括查sql，nosql去判斷該請求到底有沒有權限訪問。

叄、啓動測試

• 依次啓動eureka的服務端和兩個客戶端和lovin-feign-client、lovin-ribbon-client，以及新建的lovin-cloud-zuul
• 而後訪問http://localhost:8882/api-feign/getHello和http://localhost:8882/api-ribbon/hello，而後咱們能夠帶上token訪問來驗證過濾器

肆、網絡架構

• 咱們能夠看到咱們調用的服務再也不是像再上一篇文章中的直接訪問對應的服務，而是經過feign的Ribbon的負載均衡的去調用的，並且這裏說明一點，Ribbon的默認機制是輪詢。

---

• 最後的最後是本博客的源碼,歡迎關注這一套SpringCloud的實踐