SpringCloudGateway搭建和常见使用方法

**Spring Cloud Gateway：**提供一种简单而有效的方式来对API进行路由，并为他们提供切面，例如：安全性，监控/指标 和弹性等。

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1.如何在工程中引用Spring Cloud Gateway

• 引入jar包

         <dependency>
              <groupId>org.springframework.cloud</groupId>
              <artifactId>spring-cloud-starter-gateway</artifactId>
          </dependency>
  
          <!-- SpringCloud Ailibaba Nacos -->
          <dependency>
              <groupId>com.alibaba.cloud</groupId>
              <artifactId>spring-cloud-starter-alibaba-nacos-discovery</artifactId>
          </dependency>
  
          <!-- SpringCloud Ailibaba Nacos Config -->
          <dependency>
              <groupId>com.alibaba.cloud</groupId>
              <artifactId>spring-cloud-starter-alibaba-nacos-config</artifactId>
          </dependency>
  
          <!-- SpringBoot Actuator -->
          <dependency>
              <groupId>org.springframework.boot</groupId>
              <artifactId>spring-boot-starter-actuator</artifactId>
          </dependency>
  

• 配置注册中心地址

  spring:
    application:
      name: dyzh-gateway
    cloud:
      nacos:
        discovery:
          enabled: true
          register-enabled: true
          server-addr: 127.0.0.1:8848
  
  

• 配置路由

  • Route 路由：gateway的基本构建模块。它由ID、目标URI、断言集合和过滤器集合组成。如果聚合断言结果为真，则匹配到该路由。
  • Predicate 断言：这是一个Java 8 Function Predicate。输入类型是 Spring Framework ServerWebExchange。这允许开发人员可以匹配来自HTTP请求的任何内容，例如Header或参数。
  • Filter 过滤器：这些是使用特定工厂构建的 Spring FrameworkGatewayFilter实例。 。Spring cloud gateway中的filter分为两种类型的Filter，分别是Gateway Filter和Global Filter（全局）。过滤器Filter将会对请求和响应进行修改处理 所以可以在返回请求之前或之后修改请求和响应的内容。

  spring:
    cloud:
      gateway:
        discovery:
          locator:
            # 注册中心自动发现 默认为 false
            enabled: false
            #手动配置路由
        routes:
           #路由id，可以自定义设置
          - id: dyzh-demo-service
          #目标URI， URI上的'lb`前缀,使用Spring Cloud Netflix Ribbon 客户端负载均衡。
            uri: lb://dyzh-demo-service
            predicates:
            - Path=/sys/**
  

2.Actuator API

/gateway的actuator端点允许监视Spring Cloud Gateway应用程序并与之交互。要进行远程访问，必须在应用程序属性中暴露HTTP或JMX 端口。

• 开启actuator

  management:
    endpoint:
      gateway:
      # 默认为false
        enabled: true
    endpoints:
      web:
        exposure:
          include: gateway
  

• 下表列出了Spring Cloud Gateway执行器端点（请注意，每个端点都/actuator/gateway作为基本路径）：

ID	HTTP Method	Description
globalfilters	GET	Displays the list of global filters applied to the routes.
routefilters	GET	Displays the list of GatewayFilter factories applied to a particular route.
refresh	POST	Clears the routes cache.
routes	GET	Displays the list of routes defined in the gateway.
routes/{id}	GET	Displays information about a particular route.
routes/{id}	POST	Adds a new route to the gateway.
routes/{id}	DELETE	Removes an existing route from the gateway.

1.检索所有的路由【 global filters 】

curl -X GET http://localhost:your-port/actuator/gateway/globalfilters

​ 返回结果如下：

{
    "[e-mail]195113de": -1,
    "[e-mail]689": 2147483647,
    "[e-mail]6b0": 0,
    "[e-mail]3e900e1a": -2147482648,
    "[e-mail]9": 0,
    "[e-mail]3ebc955b": -2147483648,
    "[e-mail]5aa781f2": 2147483646,
    "[e-mail]25974207": 10100,
    "[e-mail]21a46ff1": 10000,
    "[e-mail]5f4e2": 2147483647
}

返回结果包含已就绪的global filters的详细信息(如 [e-mail]25974207。对于每个global filters，返回结果字符串对应过滤器链中的相应顺序。

2.检索所有的路由【 global filters 】

curl -X GET http://localhost:9001/actuator/gateway/routefilters

返回结果如下：

{
    "[[e-mail] configClass = RequestSizeGatewayFilterFactory.RequestSizeConfig]": null,
    "[[e-mail] configClass = AbstractNameValueGatewayFilterFactory.NameValueConfig]": null,
    "[[e-mail] configClass = RedirectToGatewayFilterFactory.Config]": null,
    "[[e-mail] configClass = RewritePathGatewayFilterFactory.Config]": null,
    "[[e-mail] configClass = RetryGatewayFilterFactory.RetryConfig]": null,
    "[[e-mail] configClass = AbstractGatewayFilterFactory.NameConfig]": null,
    "[[e-mail] configClass = StripPrefixGatewayFilterFactory.Config]": null,
    "[[e-mail] configClass = RequestHeaderSizeGatewayFilterFactory.Config]": null,
    "[[e-mail] configClass = AbstractNameValueGatewayFilterFactory.NameValueConfig]": null,
    "[[e-mail] configClass = AbstractGatewayFilterFactory.NameConfig]": null,
    "[[e-mail] configClass = SetStatusGatewayFilterFactory.Config]": null,
    "[[e-mail] configClass = ModifyRequestBodyGatewayFilterFactory.Config]": null,
    "[[e-mail] configClass = AbstractNameValueGatewayFilterFactory.NameValueConfig]": null,
    "[[e-mail] configClass = AbstractNameValueGatewayFilterFactory.NameValueConfig]": null,
    "[[e-mail] configClass = RewriteLocationResponseHeaderGatewayFilterFactory.Config]": null,
    "[[e-mail] configClass = DedupeResponseHeaderGatewayFilterFactory.Config]": null,
    "[[e-mail] configClass = Object]": null,
    "[[e-mail] configClass = AbstractGatewayFilterFactory.NameConfig]": null,
    "[[e-mail] configClass = Object]": null,
    "[[e-mail] configClass = AbstractNameValueGatewayFilterFactory.NameValueConfig]": null,
    "[[e-mail] configClass = SetPathGatewayFilterFactory.Config]": null,
    "[[e-mail] configClass = AbstractGatewayFilterFactory.NameConfig]": null,
    "[[e-mail] configClass = RewriteResponseHeaderGatewayFilterFactory.Config]": null,
    "[[e-mail] configClass = MapRequestHeaderGatewayFilterFactory.Config]": null,
    "[[e-mail] configClass = ModifyResponseBodyGatewayFilterFactory.Config]": null,
    "[[e-mail] configClass = PrefixPathGatewayFilterFactory.Config]": null,
    "[[e-mail] configClass = Object]": null
}

返回结果包含应用于所有路由的GatewayFilter的详细信息。显示每个工厂提供字符串格式的相应对象（例如， [[e-mail] configClass = Object]）。请注意，null值是由于endpoint controller实现不完整造成的，因为它尝试在filter chain中设置对象的顺序，这不适用于GatewayFilter工厂对象。

3.清除路由的缓存

curl -X POST http://localhost:9001/actuator/gateway/refresh

没有返回值，只有200的状态码

4.检测网关中定义的路由

curl -X GET http://localhost:9001/actuator/gateway/routes

返回结果如下

[
    {
        "predicate": "Paths: [/sys/**], match trailing slash: true",
        "route_id": "dyzh-demo-service",
        "filters": [],
        "uri": "lb://dyzh-demo-service",
        "order": 0
    }
]

结果中包含网关中所有定义的路由信息

Path	Type	Description
id	String	The route ID.
predicates	Array	The collection of route predicates. Each item defines the name and the arguments of a given predicate.
filters	Array	The collection of filters applied to the route.
uri	String	The destination URI of the route.
order	Number	The route order.

5.获取单个路由信息

curl -X GET http://localhost:9001/actuator/gateway/routes/{id}

返回结果如下：

{
    "predicate": "Paths: [/sys/**], match trailing slash: true",
    "route_id": "dyzh-demo-service",
    "filters": [],
    "uri": "lb://dyzh-demo-service",
    "order": 0
}

6. 创建一个路由

curl -X POST
http://localhost:9001/actuator/gateway/routes/test
-H ‘Content-Type: application/json’
-d ‘{
“id”:“dyzh-back-server”,
“uri”:“lb//dyzh-back-server”
}’

请求成功返回201的状态码

7.删除一个路由

curl -X DELETE http://localhost:9001/actuator/gateway/routes/dyzh-demo-service

3.跨域拦截

spring:
  cloud:
    gateway:
      globalcors:
        corsConfigurations:
          '[/**]':
            allowedOrigins: "https://domain"
            allowedMethods:
            - GET
            allowHeaders:
            - Content-Type

4.过滤器 GateWayFilter

Spring Cloud Gateway的filte只有两个：“pre”和“post”：

• pre:这种过滤器在请求被路由之前调用。可以利用这个过滤器实现身份验证、在集群中选择请求的微服务、记录调试的信息。

• post：这种过滤器在路由到服务器之后执行。这种过滤器可用来为响应添加HTTP Header、统计信息和指标、响应从微服务发送给客户端等。

Spring Cloud gateway的filter分为两种：GatewayFilter和Globalfilter。GlobalFilter会应用到所有的路由上，而Gatewayfilter将应用到单个路由或者一个分组的路由上。

如果要自定义一个GatewayFilter，需要实现GatewayFilterFactory。下面是一个你需要集成的抽象类 AbstractGatewayFilterFactory。

PreGatewayFilterFactory.java.

public class PreGatewayFilterFactory extends AbstractGatewayFilterFactory<PreGatewayFilterFactory.Config> {

    public PreGatewayFilterFactory() {
        super(Config.class);
    }

    @Override
    public GatewayFilter apply(Config config) {
        // grab configuration from Config object
        return (exchange, chain) -> {
            //If you want to build a "pre" filter you need to manipulate the
            //request before calling chain.filter
            ServerHttpRequest.Builder builder = exchange.getRequest().mutate();
            //use builder to manipulate the request
            return chain.filter(exchange.mutate().request(request).build());
        };
    }

    public static class Config {
        //Put the configuration properties for your filter here
    }

}

PostGatewayFilterFactory.java.

public class PostGatewayFilterFactory extends AbstractGatewayFilterFactory<PostGatewayFilterFactory.Config> {

    public PostGatewayFilterFactory() {
        super(Config.class);
    }

    @Override
    public GatewayFilter apply(Config config) {
        // grab configuration from Config object
        return (exchange, chain) -> {
            return chain.filter(exchange).then(Mono.fromRunnable(() -> {
                ServerHttpResponse response = exchange.getResponse();
                //Manipulate the response in some way
            }));
        };
    }

    public static class Config {
        //Put the configuration properties for your filter here
    }

}

5.全局过滤器 GlobalFilter

Spring Cloud Gateway根据作用范围分为GatewayFilter和GlobalFilter，二者区别如下：

GatewayFilter : 需要通过spring.cloud.routes.filters 配置在具体路由下，只作用在当前路由上或通过spring.cloud.default-filters配置在全局，作用在所有路由上。

当请求与路由匹配时，过滤Web处理程序会将的所有实例GlobalFilter和所有特定GatewayFilter于路由的实例添加到过滤器链中。该组合的过滤器链按org.springframework.core.Ordered接口排序，您可以通过实现该getOrder()方法进行设置。

ExampleConfiguration.java

@Bean
public GlobalFilter customFilter() {
    return new CustomGlobalFilter();
}

public class CustomGlobalFilter implements GlobalFilter, Ordered {

    @Override
    public Mono<Void> filter(ServerWebExchange exchange, GatewayFilterChain chain) {
        log.info("custom global filter");
        return chain.filter(exchange);
    }

    @Override
    public int getOrder() {
        return -1;
    }
}

6.http超时配置

connect-timeout必须以毫秒为单位指定。 response-timeout必须指定为java.time.Duration

• 全局http超时示例

spring:
  cloud:
    gateway:
      httpclient:
        connect-timeout: 1000
        response-timeout: 5s

• 要配置每个路由超时：
  connect-timeout必须以毫秒为单位指定。
  response-timeout必须以毫秒为单位指定

- id: per_route_timeouts
        uri: https://example.org
        predicates:
          - name: Path
            args:
              pattern: /delay/{timeout}
        metadata:
          response-timeout: 200
          connect-timeout: 200

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