一起来学SpringCloud之 - 路由网关(Zuul)

文章目录
  1. 1. - Zuul
  2. 2. - 准备工作
    1. 2.1. - battcn-gateway-service
    2. 2.2. - battcn-hello-service
    3. 2.3. - 测试一把
      1. 2.3.1. - 自定义过滤器
      2. 2.3.2. - 路由映射流程
      3. 2.3.3. - Zuul Fallback
  3. 3. - 路由配置详解
  4. 4. - 说点什么

上一篇已经讲了微服务组件中的 分布式配置中心,本章讲述 由JAVA编写的服务路由网关Zuul

- Zuul

路由是微服务体系结构的一个组成部分。例如 / 可以映射到您的Web应用程序,/api/users映射到用户服务,/api/shop映射到商店服务。Zuul是Netflix的基于JVM的开发的路由和服务器端负载均衡器。

为什么需要服务网关?

如果没有服务网关,多个服务提供给前端调用地址管理错综复杂,增加了客户端的复杂性,认证也相对麻烦,每个服务都需要编写相同的认证….

Zuul架构图

画图工具:https://www.processon.com/

Zuul 可以做什么?

  • 身份认证
  • 审查与监控
  • 压力测试
  • 金丝雀测试
  • 动态路由
  • 服务迁移
  • 负载分配
  • 安全
  • 静态响应处理
  • 主动/主动流量管理

Zuul的规则引擎允许基本上写任何JVM语言的规则和过滤器,内置Java和Groovy的支持。

注意:配置属性 zuul.max.host.connections 已被取代的两个新的属性,zuul.host.maxTotalConnections并且zuul.host.maxPerRouteConnections 它的缺省值分别200和20。

注意:所有路线的默认Hystrix隔离模式(ExecutionIsolationStrategy)为SEMAPHOREzuul.ribbonIsolationStrategy 如果此隔离模式是首选,可以更改为THREAD

官方文档:http://cloud.spring.io/spring-cloud-static/Dalston.SR2/#_router_and_filter_zuul

- 准备工作

1.启动Consul
2.创建 battcn-gateway-servicebattcn-hello-service

- battcn-gateway-service

1.在项目 pom.xml 中添加 ZUUL 依赖

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
<dependencies>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-zuul</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-consul-discovery</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-actuator</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
</dependency>
</dependencies>

2.App.java中开启 zuul 代理

1
2
3
4
5
6
7
8
9
@EnableZuulProxy
@EnableDiscoveryClient
@SpringBootApplication
public class ZuulApplication {

public static void main(String[] args) {
SpringApplication.run(ZuulApplication.class, args);
}
}

3.zuul.routes.routesName.ZuulProperties.ZuulRoute 配置的方式,详细可以参考源码org.springframework.cloud.netflix.zuul.filters.ZuulProperties

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
server:
port: 9000

zuul:
routes:
hello-service: #自定义的 路由名称
path: /api-hello/** #路由路径
serviceId: battcn-hello-service #VIP 模式中的 serviceId

spring:
application:
name: battcn-gateway-service
cloud:
consul:
host: localhost
port: 8500
enabled: true
discovery:
enabled: true
prefer-ip-address: true

- battcn-hello-service

hello-service 只需要以下依赖,能注册到consul中就行(单纯的一个服务)

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
<dependencies>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-consul-discovery</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-actuator</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
</dependency>
</dependencies>
1
2
3
4
5
6
7
8
@EnableDiscoveryClient
@SpringBootApplication
public class HelloApplication {

public static void main(String[] args) {
SpringApplication.run(HelloApplication.class, args);
}
}
1
2
3
4
5
6
7
8
9
10
11
12
13
14
server:
port: 9001

spring:
application:
name: battcn-hello-service
cloud:
consul:
host: localhost
port: 8500
enabled: true
discovery:
enabled: true
prefer-ip-address: true

- 测试一把

访问:http://localhost:9000/api-hello/hello 从地址中可以看出我们访问的是 battcn-gateway-service,且满足 zuul.routes.routesName.path 规则,因此实际请求地址是http://localhost:9001/hello

1
hello:battcn-hello-service		#表示请求成功

- 自定义过滤器

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
import com.netflix.zuul.ZuulFilter;
import com.netflix.zuul.context.RequestContext;
import org.springframework.stereotype.Component;

import javax.servlet.http.HttpServletRequest;

/**
* 网关认证过滤器(Demo演示,实际根据自身业务考虑实现)
* @author Levin
* @date 2017-08-14.
*/
@Component
public class GatewayZuulFilter extends ZuulFilter {

/**
* per:路由之前,如实现认证、记录调试信息等
* routing:路由时
* post:路由后,比如添加HTTP Header
* error:发生错误时调用
*/
@Override
public String filterType() {
return "pre";
}

/**
* 过滤器顺序,类似@Filter中的order
*/
@Override
public int filterOrder() {
return 0;
}

/**
* 这里可以写逻辑判断,是否要过滤,本文true,永远过滤。
*/
@Override
public boolean shouldFilter() {
return true;
}

/**
* 过滤器的具体逻辑。可用很复杂,包括查sql,nosql去判断该请求到底有没有权限访问。
*/
@Override
public Object run() {
RequestContext ctx = RequestContext.getCurrentContext();
HttpServletRequest request = ctx.getRequest();
String token = request.getParameter("token");
if(token == null) {
ctx.setSendZuulResponse(false);
ctx.setResponseStatusCode(404);
ctx.setResponseBody("token cannot be empty");
}
return null;
}
}

实际开发中token应该从请求头中获取,该处只是为了方便演示效果

访问:http://localhost:9000/api-hello/hello?token=1

1
hello:battcn-hello-service

访问:http://localhost:9000/api-hello/hello

1
token cannot be empty

- 路由映射流程

图不是很严谨,凑合着看看吧…

HanderMapping

初次启动项目我们可以看到

1
2
3
4
2017-08-14 17:19:06.090  INFO 11544 --- [nio-9000-exec-1] o.s.c.n.zuul.web.ZuulHandlerMapping      : Mapped URL path [/api-hello/**] onto handler of type [class org.springframework.cloud.netflix.zuul.web.ZuulController]
2017-08-14 17:19:06.090 INFO 11544 --- [nio-9000-exec-1] o.s.c.n.zuul.web.ZuulHandlerMapping : Mapped URL path [/battcn-gateway-service/**] onto handler of type [class org.springframework.cloud.netflix.zuul.web.ZuulController]
2017-08-14 17:19:06.090 INFO 11544 --- [nio-9000-exec-1] o.s.c.n.zuul.web.ZuulHandlerMapping : Mapped URL path [/battcn-hello-service/**] onto handler of type [class org.springframework.cloud.netflix.zuul.web.ZuulController]
2017-08-14 17:19:06.090 INFO 11544 --- [nio-9000-exec-1] o.s.c.n.zuul.web.ZuulHandlerMapping : Mapped URL path [/consul/**] onto handler of type [class org.springframework.cloud.netflix.zuul.web.ZuulController]

有兴趣的还可以阅读下 com.netflix.loadbalancer.LoadBalancerContext,通过它可以发现每次请求的IP和端口,需要在application.yml 中配置

1
2
3
logging:
level:
com.netflix: DEBUG
1
2
3
4
5
6
2017-08-14 17:32:16.793 DEBUG 14316 --- [nio-9000-exec-7] c.n.zuul.http.HttpServletRequestWrapper  : Path = null
2017-08-14 17:32:16.793 DEBUG 14316 --- [nio-9000-exec-7] c.n.zuul.http.HttpServletRequestWrapper : Transfer-Encoding = null
2017-08-14 17:32:16.793 DEBUG 14316 --- [nio-9000-exec-7] c.n.zuul.http.HttpServletRequestWrapper : Content-Encoding = null
2017-08-14 17:32:16.793 DEBUG 14316 --- [nio-9000-exec-7] c.n.zuul.http.HttpServletRequestWrapper : Content-Length header = -1
2017-08-14 17:32:16.793 DEBUG 14316 --- [nio-9000-exec-7] c.n.loadbalancer.ZoneAwareLoadBalancer : Zone aware logic disabled or there is only one zone
2017-08-14 17:32:16.793 DEBUG 14316 --- [nio-9000-exec-7] c.n.loadbalancer.LoadBalancerContext : battcn-hello-service using LB returned Server: 192.168.31.221:9001 for request /hello

- Zuul Fallback

定义GatewayZuulFallback 实现 ZuulFallbackProvider 接口

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
/**
* @author Levin
* @date 2017-08-14.
*/
@Component
public class GatewayZuulFallback implements ZuulFallbackProvider {
@Override
public String getRoute() {
return "battcn-hello-service";//指定回退的服务名
}

@Override
public ClientHttpResponse fallbackResponse() {
return new ClientHttpResponse() {
@Override
public HttpStatus getStatusCode() throws IOException {
return HttpStatus.INTERNAL_SERVER_ERROR; //INTERNAL_SERVER_ERROR(500, "Internal Server Error")
}

@Override
public int getRawStatusCode() throws IOException {
return this.getStatusCode().value();// 500
}

@Override
public String getStatusText() throws IOException {
return this.getStatusCode().getReasonPhrase();// Internal Server Error
}

@Override
public void close() {}

@Override
public InputStream getBody() throws IOException {
return new ByteArrayInputStream(getStatusText().getBytes());//也可以随意写自己想返回的内容
}

@Override
public HttpHeaders getHeaders() {
HttpHeaders httpHeaders = new HttpHeaders();
httpHeaders.setContentType(MediaType.APPLICATION_JSON_UTF8);
return httpHeaders;
}
};
}
}

步骤:停掉 battcn-hello-service 启动 battcn-gateway-service

访问:http://localhost:9000/api-hello/hello?token=1

显示:

1
Internal Server Error  # 代表Fallback成功

- 路由配置详解

zuul 相关的官方文档还是比较其全了,本文也是参考官方然后简单讲述应用场景,具体开发请结合自身业务扩展….

1.自定义指定微服务路径,以下两种配置方式结果相同

1
2
3
4
5
6
7
8
9
zuul:
routes:
battcn-hello-service: /api-hello/**
#两种配置方式结果相同
zuul:
routes:
hello-service:
path: /api-hello/**
serviceId: battcn-hello-service

2.忽略指定服务,多个服务逗号分隔,Set<String> ignoredServices 这样一来zuul就会忽略service1和service2,只会代理其它的

1
2
zuul:
ignored-services: battcn-hello-service1,battcn-hello-service2

3.指定Path和Url

1
2
3
4
5
zuul:
routes:
hello-service:
path: /api-hello/** #路由路径
url: http://localhost:9001/ #指定URL地址

4.使用Zuul但不指定Url(该方式在Eureka有效,Consul还未找到解决方法…)

1
2
3
4
5
6
7
8
9
zuul:
routes:
battcn-hello-service: /api-hello/**
ribbon:
eureka:
enabled: false #为Ribbon禁用 eureka,不会破坏Zuul的Hystrix和Ribbon特性
battcn-hello-service:
ribbon:
listOfServers: localhost:9001,localhost:9002

- 说点什么

本章代码(battcn-gateway-service/battcn-hello-service):https://git.oschina.net/battcn/battcn-cloud/tree/master/battcn-cloud-zuul

如有问题请及时与我联系

  • 个人QQ:1837307557
  • Spring Cloud中国社区①:415028731
  • Spring For All 社区⑤:157525002