Gateway网关限流

网关限流基本介绍

网关是所有请求的公共入口，所以可以在网关进行限流，而且限流的方式也很多，我们本次采用前面学过的Sentinel组件来实现网关的限流。Sentinel支持对SpringCloud Gateway、Zuul等主流网关进行限流。

从1.6.0版本开始，Sentinel提供了SpringCloud Gateway的适配模块，可以提供两种资源维度的限流：

route维度：即在Spring配置文件中配置的路由条目，资源名为对应的routeId

自定义API维度：用户可以利用Sentinel提供的API来自定义一些API分组

使用网关限流

在网关模块导入依赖

        <!--引入网关限流-->
        <dependency>
            <groupId>com.alibaba.csp</groupId>
            <artifactId>sentinel-spring-cloud-gateway-adapter</artifactId>
            <version>1.8.1</version>
        </dependency>

编写配置类

基于Sentinel 的Gateway限流是通过其提供的Filter来完成的，使用时只需注入对应的SentinelGatewayFilter实例以及 SentinelGatewayBlockExceptionHandler 实例即可。

package com.apigateway.config;
import com.alibaba.csp.sentinel.adapter.gateway.common.rule.GatewayFlowRule;
import com.alibaba.csp.sentinel.adapter.gateway.common.rule.GatewayRuleManager;
import com.alibaba.csp.sentinel.adapter.gateway.sc.SentinelGatewayFilter;
import com.alibaba.csp.sentinel.adapter.gateway.sc.callback.BlockRequestHandler;
import com.alibaba.csp.sentinel.adapter.gateway.sc.callback.GatewayCallbackManager;
import com.alibaba.csp.sentinel.adapter.gateway.sc.exception.SentinelGatewayBlockExceptionHandler;
import org.springframework.cloud.gateway.filter.GlobalFilter;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.core.Ordered;
import org.springframework.core.annotation.Order;
import org.springframework.http.HttpStatus;
import org.springframework.http.MediaType;
import org.springframework.http.codec.ServerCodecConfigurer;
import org.springframework.web.reactive.function.BodyInserters;
import org.springframework.web.reactive.function.server.ServerResponse;
import org.springframework.web.reactive.result.view.ViewResolver;
import org.springframework.web.server.ServerWebExchange;
import reactor.core.publisher.Mono;
import javax.annotation.PostConstruct;
import java.util.*;
/**
网关限流配置API
*/
@Configuration
public class GatewayConfiguration{
    private final List<ViewResolver> viewResolvers;
    private final ServerCodecConfigurer serverCodecConfigurer;
    public GatewayConfiguration(List<ViewResolver> viewResolversProvider, ServerCodecConfigurer serverCodecConfigurer) {
        this.viewResolvers = viewResolversProvider;
        this.serverCodecConfigurer = serverCodecConfigurer;
    }

     // 初始化一个限流的过滤器
    @Bean
    @Order(Ordered.HIGHEST_PRECEDENCE)
    public GlobalFilter sentinelGatewayFilter() {
        return new SentinelGatewayFilter();
    }

    // 配置初始化的限流参数    
    @PostConstruct
    public void initGatewayRules() {
        Set<GatewayFlowRule> rules = new HashSet<>();
        rules.add(new GatewayFlowRule("api-ce")//资源名称,对应路由id
        .setCount(1) // 限流阈值
        .setIntervalSec(1) // 统计时间窗口，单位是秒，默认是 1 秒      
        );GatewayRuleManager.loadRules(rules);
    }

     // 配置限流的异常处理器    
    @Bean
    @Order(Ordered.HIGHEST_PRECEDENCE)
    public SentinelGatewayBlockExceptionHandler sentinelGatewayBlockExceptionHandler() {
        return new SentinelGatewayBlockExceptionHandler(viewResolvers, serverCodecConfigurer);
    }
    //自定义限流异常页面
    @PostConstruct
    public void initBlockHandlers(){
        BlockRequestHandler blockRequestHandler=new BlockRequestHandler(){
            @Override
            public Mono<ServerResponse> handleRequest(ServerWebExchange serverWebExchange, Throwable throwable) {
                 Map map = new HashMap<>();
                 map.put("code", 0);
                 map.put("message", "接口被限流了");
                 return ServerResponse.status(HttpStatus.OK).
                  contentType(MediaType.APPLICATION_JSON_UTF8).
                  body(BodyInserters.fromObject(map));
            }
        };
        GatewayCallbackManager.setBlockHandler(blockRequestHandler);
    }
}

测试

在一秒钟内多次访问http://localhost:7000/test/index/就可以看到限流启作用了。

自定义API分组

修改配置文件

@Configuration
public class GatewayConfiguration{
    private final List<ViewResolver> viewResolvers;
    private final ServerCodecConfigurer serverCodecConfigurer;
    public GatewayConfiguration(List<ViewResolver> viewResolversProvider, ServerCodecConfigurer serverCodecConfigurer) {
        this.viewResolvers = viewResolversProvider;
        this.serverCodecConfigurer = serverCodecConfigurer;
    }

     // 初始化一个限流的过滤器
    @Bean
    @Order(Ordered.HIGHEST_PRECEDENCE)
    public GlobalFilter sentinelGatewayFilter() {
        return new SentinelGatewayFilter();
    }

    // 配置初始化的限流参数    
    @PostConstruct
    public void initGatewayRules() {
       //product_api1 分组的名称
        Set<GatewayFlowRule> rules = new HashSet<> ();
        rules.add(new GatewayFlowRule( "product_api1").setCount(1).setIntervalSec(1) );
        rules.add(new GatewayFlowRule( "product_api2").setCount(1).setIntervalSec(1) );
        GatewayRuleManager .loadRules (rules);
    }

     // 配置限流的异常处理器    
    @Bean
    @Order(Ordered.HIGHEST_PRECEDENCE)
    public SentinelGatewayBlockExceptionHandler sentinelGatewayBlockExceptionHandler() {
        return new SentinelGatewayBlockExceptionHandler(viewResolvers, serverCodecConfigurer);
    }
    //自定义限流异常页面
    @PostConstruct
    public void initBlockHandlers(){
        BlockRequestHandler blockRequestHandler=new BlockRequestHandler(){
            @Override
            public Mono<ServerResponse> handleRequest(ServerWebExchange serverWebExchange, Throwable throwable) {
                 Map map = new HashMap<>();
                 map.put("code", 0);
                 map.put("message", "接口被限流了");
                 return ServerResponse.status(HttpStatus.OK).
                  contentType(MediaType.APPLICATION_JSON_UTF8).
                  body(BodyInserters.fromObject(map));
            }
        };
        GatewayCallbackManager.setBlockHandler(blockRequestHandler);
    }

    /**
     * 自定义API分组
     */
    @PostConstruct
     private void initCustomizedApis() {
     Set<ApiDefinition> definitions = new HashSet<>();
     ApiDefinition api1 = new ApiDefinition("product_api1")
             .setPredicateItems(new HashSet<ApiPredicateItem>() {{
                 // 以/test/product/api1开头的请求 限流的路径
                 add(new ApiPathPredicateItem().setPattern("/test/api1/**").
                         setMatchStrategy(SentinelGatewayConstants.URL_MATCH_STRATEGY_PREFIX));
             }});
      ApiDefinition api2 = new ApiDefinition("product_api2")
                .setPredicateItems(new HashSet<ApiPredicateItem>() {{
                     // 以/test/api2/demo1 完成的url路径匹配
                    add(new ApiPathPredicateItem().setPattern("/test/api2/demo1"));
             }});
      definitions.add(api1);
      definitions.add(api2);
      GatewayApiDefinitionManager.loadApiDefinitions(definitions);
    }
}

在测试模块编写

@RestController("/test")
public class TestController {

    @RequestMapping("/api1/demo1")
    public String demo1() {
        return "demo1";
    }

    @RequestMapping("/api1/demo2")
    public String demo2() {
        return "demo2";
    }

    @RequestMapping("/api2/demo1")
    public String demo3() {
        return "demo3";
    }

    @RequestMapping("/api2/demo2")
    public String demo4() {
        return "demo4";
    }

}

测试