spring cloud進階五 [路由閘道器 (zuul)]
在微服務架構中,需要幾個基礎的服務治理元件,包括服務註冊與發現、服務消費、負載均衡、斷路器、智慧路由、配置管理等,由這幾個基礎元件相互協作,共同組建了一個簡單的微服務系統。一個簡答的微服務系統如下圖:
在Spring Cloud微服務系統中,一種常見的負載均衡方式是,客戶端的請求首先經過負載均衡(zuul、Ngnix),再到達服務閘道器(zuul叢集),然後再到具體的服務,服務統一註冊到高可用的服務註冊中心叢集,服務的所有的配置檔案由配置服務管理(下一篇文章講述),配置服務的配置檔案放在git倉庫,方便開發人員隨時改配置。
一、Zuul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,比如/api/user轉發到到user服務,/api/shop轉發到到shop服務。zuul預設和Ribbon結合實現了負載均衡的功能。
zuul有以下功能:
- Authentication
- Insights
- Stress Testing
- Canary Testing
- Dynamic Routing
- Service Migration
- Load Shedding
- Security
- Static Response handling
- Active/Active traffic management
二、建立service-zuul工程
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.gui.springzuul</groupId> <artifactId>serverzuul</artifactId> <version>0.0.1-SNAPSHOT</version> <packaging>jar</packaging> <name>serverzuul</name> <description>Demo project for Spring Boot</description> <parent> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-parent</artifactId> <version>2.0.2.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.RC2</spring-cloud.version> </properties> <dependencies> <dependency> <groupId>org.springframework.cloud</groupId> <artifactId>spring-cloud-starter-netflix-eureka-server</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-web</artifactId> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-test</artifactId> <scope>test</scope> </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> <repositories> <repository> <id>spring-milestones</id> <name>Spring Milestones</name> <url>https://repo.spring.io/milestone</url> <snapshots> <enabled>false</enabled> </snapshots> </repository> </repositories> </project>
application.yml
server: port: 8769 eureka: client: service-url: defaultZone: http://localhost:8761/eureka/ spring: application: name: service-zuul zuul: routes: api-a: path: /api-a/** serviceId: service-ribbon api-b: path: /api-b/** serviceId: service-feign
ServerzuulApplication.java
package com.gui.springzuul.serverzuul; 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; @EnableEurekaClient @EnableZuulProxy @SpringBootApplication public class ServerzuulApplication { public static void main(String[] args) { SpringApplication.run(ServerzuulApplication.class, args); } }
首先指定服務註冊中心的地址為http://localhost:8761/eureka/,服務的埠為8769,服務名為service-zuul;以/api-a/ 開頭的請求都轉發給service-ribbon服務;以/api-b/開頭的請求都轉發給service-feign服務;
依次執行這五個工程;開啟瀏覽器訪問:http://localhost:8769/api-a/hi?name=forezp ;瀏覽器顯示:
hi forezp,i am from port:8762
開啟瀏覽器訪問:http://localhost:8769/api-b/hi?name=forezp ;瀏覽器顯示:
hi forezp,i am from port:8762
這說明zuul起到了路由的作用
四、服務過濾
zuul不僅只是路由,並且還能過濾,做一些安全驗證。繼續改造工程;
@Component
public class MyFilter extends ZuulFilter{
private static Logger log = LoggerFactory.getLogger(MyFilter.class);
@Override
public String filterType() {
return "pre";
}
@Override
public int filterOrder() {
return 0;
}
@Override
public boolean shouldFilter() {
return true;
}
@Override
public Object run() {
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;
}
log.info("ok");
return null;
}
}
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- filterType:返回一個字串代表過濾器的型別,在zuul中定義了四種不同生命週期的過濾器型別,具體如下:
- pre:路由之前
- routing:路由之時
- post: 路由之後
- error:傳送錯誤呼叫
- filterOrder:過濾的順序
- shouldFilter:這裡可以寫邏輯判斷,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許可權訪問。
這時訪問:http://localhost:8769/api-a/hi?name=forezp ;網頁顯示:
token is empty
訪問 http://localhost:8769/api-a/hi?name=forezp&token=22 ;
網頁顯示:
hi forezp,i am from port:8762