使用springcloud gateway搭建网关（分流，限流，…

2018-12-17 10:47:39来源：博客园阅读 ()

Spring Cloud Gateway

Spring Cloud Gateway 是 Spring Cloud 的一个全新项目，该项目是基于 Spring 5.0，Spring Boot 2.0 和 Project Reactor 等技术开发的网关，它旨在为微服务架构提供一种简单有效的统一的 API 路由管理方式。

Spring Cloud Gateway 作为 Spring Cloud 生态系统中的网关，目标是替代 Netflix Zuul，其不仅提供统一的路由方式，并且基于 Filter 链的方式提供了网关基本的功能，例如：安全，监控/指标，和限流。

快速上手

引入spring-boot 2.1.1.RELEASE ，springcloud的版本为 Greenwich.M3

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.1.1.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    
    <properties>
        <java.version>1.8</java.version>
        <spring-cloud.version>Greenwich.M3</spring-cloud.version>
    </properties>
    
    <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>

添加的依赖包如下

        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-gateway</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-netflix-hystrix</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-webflux</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-redis-reactive</artifactId>
        </dependency>

注意springcloud gateway使用的web框架为webflux，和springMVC不兼容。引入的限流组件是hystrix。redis底层不再使用jedis，而是lettuce。

路由断言

接下来就是配置了，可以使用java代码硬编码配置路由过滤器，也可以使用yml配置文件配置。下面我们首先介绍配置文件配置方式

application.yml

server.port: 8082

spring:
  application:
    name: gateway
  cloud:
    gateway:
      routes:
        - id: path_route
          uri: http://localhost:8000
          order: 0
          predicates:
            - Path=/foo/**
          filters:
            - StripPrefix=1

上面给出了一个根据请求路径来匹配目标uri的例子，如果请求的路径为/foo/bar，则目标uri为 http://localhost:8000/bar。如果上面例子中没有加一个StripPrefix=1过滤器，则目标uri 为http://localhost:8000/foo/bar，StripPrefix过滤器是去掉一个路径。

其他的路由断言和过滤器使用方法请查看官网

https://cloud.spring.io/spring-cloud-static/spring-cloud-gateway/2.1.0.RC2/single/spring-cloud-gateway.html#gateway-how-it-works

接下来我们来看一下设计一个网关应该需要的一些功能

修改接口返回报文

因为网关路由的接口返回报文格式各异，并且网关也有有一些限流、认证、熔断降级的返回报文，为了统一这些报文的返回格式，网关必须要对接口的返回报文进行修改，过滤器代码如下：

package org.gateway.filter.global;

import java.nio.charset.Charset;

import org.gateway.response.Response;
import org.reactivestreams.Publisher;
import org.springframework.cloud.gateway.filter.GatewayFilterChain;
import org.springframework.cloud.gateway.filter.GlobalFilter;
import org.springframework.core.Ordered;
import org.springframework.core.io.buffer.DataBuffer;
import org.springframework.core.io.buffer.DataBufferFactory;
import org.springframework.core.io.buffer.DataBufferUtils;
import org.springframework.http.server.reactive.ServerHttpResponse;
import org.springframework.http.server.reactive.ServerHttpResponseDecorator;
import org.springframework.stereotype.Component;
import org.springframework.web.server.ServerWebExchange;

import com.alibaba.fastjson.JSON;

import reactor.core.publisher.Flux;
import reactor.core.publisher.Mono;

@Component
public class WrapperResponseFilter implements GlobalFilter, Ordered {
    @Override
    public int getOrder() {
        // -1 is response write filter, must be called before that
        return -2;
    }

    @Override
    public Mono<Void> filter(ServerWebExchange exchange, GatewayFilterChain chain) {
        ServerHttpResponse originalResponse = exchange.getResponse();
        DataBufferFactory bufferFactory = originalResponse.bufferFactory();
        ServerHttpResponseDecorator decoratedResponse = new ServerHttpResponseDecorator(originalResponse) {
            @Override
            public Mono<Void> writeWith(Publisher<? extends DataBuffer> body) {
                if (body instanceof Flux) {
                    Flux<? extends DataBuffer> fluxBody = (Flux<? extends DataBuffer>) body;
                    return super.writeWith(fluxBody.map(dataBuffer -> {
                        // probably should reuse buffers
                        byte[] content = new byte[dataBuffer.readableByteCount()];
                        dataBuffer.read(content);
                        // 释放掉内存
                        DataBufferUtils.release(dataBuffer);
                        String rs = new String(content, Charset.forName("UTF-8"));
                        Response response = new Response();
                        response.setCode("1");
                        response.setMessage("请求成功");
                        response.setData(rs);
                        
                        byte[] newRs = JSON.toJSONString(response).getBytes(Charset.forName("UTF-8"));
                        originalResponse.getHeaders().setContentLength(newRs.length);//如果不重新设置长度则收不到消息。
                        return bufferFactory.wrap(newRs);
                    }));
                }
                // if body is not a flux. never got there.
                return super.writeWith(body);
            }
        };
        // replace response with decorator
        return chain.filter(exchange.mutate().response(decoratedResponse).build());
    }
}

需要注意的是order需要小于-1，需要先于NettyWriteResponseFilter过滤器执行。

有了一个这样的过滤器，我们就可以统一返回报文格式了。

认证

以下提供一个简单的认证过滤器

package org.gateway.filter.global;

import java.nio.charset.StandardCharsets;

import org.gateway.response.Response;
import org.springframework.cloud.gateway.filter.GatewayFilterChain;
import org.springframework.cloud.gateway.filter.GlobalFilter;
import org.springframework.core.io.buffer.DataBuffer;
import org.springframework.http.HttpStatus;
import org.springframework.http.server.reactive.ServerHttpResponse;
import org.springframework.stereotype.Component;
import org.springframework.web.server.ServerWebExchange;

import com.alibaba.fastjson.JSON;

import reactor.core.publisher.Mono;

@Component
public class AuthFilter implements GlobalFilter{
    @Override
    public Mono<Void> filter(ServerWebExchange exchange, GatewayFilterChain chain) {
        String token = exchange.getRequest().getHeaders().getFirst("token");
        if ("token".equals(token)) {
            return chain.filter(exchange);
        }
        ServerHttpResponse response = exchange.getResponse();
        Response data = new Response();
        data.setCode("401");
        data.setMessage("非法请求");
        byte[] datas = JSON.toJSONString(data).getBytes(StandardCharsets.UTF_8);
        DataBuffer buffer = response.bufferFactory().wrap(datas);
        response.setStatusCode(HttpStatus.UNAUTHORIZED);
        response.getHeaders().add("Content-Type", "application/json;charset=UTF-8");
        return response.writeWith(Mono.just(buffer));
    }
}

限流

springcloud gateway 为我们提供了限流过滤器RequestRateLimiterGatewayFilterFactory，和限流的实现类RedisRateLimiter使用令牌桶限流。但是官方的不一定满足我们的需求，所以我们重新写一个过滤器（基本和官方一致），只是将官方的返回报文改了。

package org.gateway.limiter;

import java.nio.charset.StandardCharsets;
import java.util.Map;

import org.gateway.response.Response;
import org.springframework.cloud.gateway.filter.GatewayFilter;
import org.springframework.cloud.gateway.filter.factory.AbstractGatewayFilterFactory;
import org.springframework.cloud.gateway.filter.ratelimit.KeyResolver;
import org.springframework.cloud.gateway.filter.ratelimit.RateLimiter;
import org.springframework.cloud.gateway.route.Route;
import org.springframework.cloud.gateway.support.ServerWebExchangeUtils;
import org.springframework.core.io.buffer.DataBuffer;
import org.springframework.http.HttpStatus;
import org.springframework.http.server.reactive.ServerHttpResponse;

import com.alibaba.fastjson.JSON;

import reactor.core.publisher.Mono;

/**
 * User Request Rate Limiter filter. See https://stripe.com/blog/rate-limiters and
 */
public class RateLimiterGatewayFilterFactory extends AbstractGatewayFilterFactory<RateLimiterGatewayFilterFactory.Config> {

    public static final String KEY_RESOLVER_KEY = "keyResolver";

    private final RateLimiter defaultRateLimiter;
    private final KeyResolver defaultKeyResolver;

    public RateLimiterGatewayFilterFactory(RateLimiter defaultRateLimiter,
                                                  KeyResolver defaultKeyResolver) {
        super(Config.class);
        this.defaultRateLimiter = defaultRateLimiter;
        this.defaultKeyResolver = defaultKeyResolver;
    }

    public KeyResolver getDefaultKeyResolver() {
        return defaultKeyResolver;
    }

    public RateLimiter getDefaultRateLimiter() {
        return defaultRateLimiter;
    }

    @SuppressWarnings("unchecked")
    @Override
    public GatewayFilter apply(Config config) {
        KeyResolver resolver = (config.keyResolver == null) ? defaultKeyResolver : config.keyResolver;
        RateLimiter<Object> limiter = (config.rateLimiter == null) ? defaultRateLimiter : config.rateLimiter;

        return (exchange, chain) -> {
            Route route = exchange.getAttribute(ServerWebExchangeUtils.GATEWAY_ROUTE_ATTR);

            return resolver.resolve(exchange).flatMap(key ->
                    // TODO: if key is empty?
                    limiter.isAllowed(route.getId(), key).flatMap(response -> {

                        for (Map.Entry<String, String> header : response.getHeaders().entrySet()) {
                            exchange.getResponse().getHeaders().add(header.getKey(), header.getValue());
                        }

                        if (response.isAllowed()) {
                            return chain.filter(exchange);
                        }
                        ServerHttpResponse rs = exchange.getResponse();
                        Response data = new Response();
                        data.setCode("101");
                        data.setMessage("访问过快");
                        byte[] datas = JSON.toJSONString(data).getBytes(StandardCharsets.UTF_8);
                        DataBuffer buffer = rs.bufferFactory().wrap(datas);
                        rs.setStatusCode(HttpStatus.UNAUTHORIZED);
                        rs.getHeaders().add("Content-Type", "application/json;charset=UTF-8");
                        return rs.writeWith(Mono.just(buffer));
                    }));
        };
    }

    public static class Config {
        private KeyResolver keyResolver;
        private RateLimiter rateLimiter;
        private HttpStatus statusCode = HttpStatus.TOO_MANY_REQUESTS;

        public KeyResolver getKeyResolver() {
            return keyResolver;
        }

        public Config setKeyResolver(KeyResolver keyResolver) {
            this.keyResolver = keyResolver;
            return this;
        }
        public RateLimiter getRateLimiter() {
            return rateLimiter;
        }

        public Config setRateLimiter(RateLimiter rateLimiter) {
            this.rateLimiter = rateLimiter;
            return this;
        }

        public HttpStatus getStatusCode() {
            return statusCode;
        }

        public Config setStatusCode(HttpStatus statusCode) {
            this.statusCode = statusCode;
            return this;
        }
    }

}

然后限流必须要有一个key，根据什么来进行限流，ip，接口，或者用户来进行限流，所以我们自定义一个KeyResolver

package org.gateway.limiter;

import org.springframework.cloud.gateway.filter.ratelimit.KeyResolver;
import org.springframework.web.server.ServerWebExchange;

import com.alibaba.fastjson.JSON;

import reactor.core.publisher.Mono;

public class CustomKeyResolver implements KeyResolver {

    public static final String BEAN_NAME = "customKeyResolver";

    @Override
    public Mono<String> resolve(ServerWebExchange exchange) {
        return Mono.just(getKey(exchange));
    }

    /**
     * 
     * @param exchange
     * @return
     */
    private String getKey(ServerWebExchange exchange) {
        
        LimitKey limitKey = new LimitKey();
        
        limitKey.setApi(exchange.getRequest().getPath().toString());
        limitKey.setBiz(exchange.getRequest().getQueryParams().getFirst("biz"));

        return JSON.toJSONString(limitKey);
    }
}

最后RedisRateLimiter我们也需要重写，因为不支持多级限流，原生的只会判断一个key。代码如下：

    /**
     * This uses a basic token bucket algorithm and relies on the fact that Redis scripts
     * execute atomically. No other operations can run between fetching the count and
     * writing the new count.
     */
    @Override
    public Mono<Response> isAllowed(String routeId, String id) {
        if (!this.initialized.get()) {
            throw new IllegalStateException("RedisRateLimiter is not initialized");
        }

        LimitConfig limitConfig = getLimitConfig(routeId);
        
        if (limitConfig == null || limitConfig.getTokenConfig().size()==0) {
            return Mono.just(new Response(true,null));
        }

        Map<String, Config> conf = limitConfig.getTokenConfig();
        
        LimitKey limitKey = JSON.parseObject(id, LimitKey.class);
        //api限流
        String api = limitKey.getApi();
        Config apiConf = conf.get(api);
        //业务方限流
        String biz = limitKey.getBiz();
        Config bizConf = conf.get(biz);
        
        if (apiConf!=null) {
            return isSingleAllow(api,routeId,apiConf).flatMap(res -> {
                if (res.isAllowed()) {
                    if(bizConf!=null) {
                        return isSingleAllow(biz, routeId, bizConf);
                    }else {
                        return Mono.just(new Response(true,new HashMap<>()));
                    }
                }else {
                    return Mono.just(res);
                }
            } );
        }else {
            if (bizConf!=null) {
                return isSingleAllow(biz, routeId, bizConf);
            }else {
                return Mono.just(new Response(true,new HashMap<>()));
            }
        }
    }

    /**
     * 单级限流
     * @param api
     * @param routeId
     * @param apiConf
     * @return 
     */
    private Mono<Response> isSingleAllow(String key, String routeId, Config config) {
        // How many requests per second do you want a user to be allowed to do?
        int replenishRate = config.getReplenishRate();

        // How much bursting do you want to allow?
        int burstCapacity = config.getBurstCapacity();

        try {
            List<String> keys = getKeys(routeId+"$"+key);

            // The arguments to the LUA script. time() returns unixtime in seconds.
            List<String> scriptArgs = Arrays.asList(replenishRate + "", burstCapacity + "",
                    Instant.now().getEpochSecond() + "", "1");
            // allowed, tokens_left = redis.eval(SCRIPT, keys, args)
            Flux<List<Long>> flux = this.redisTemplate.execute(this.script, keys, scriptArgs);
                    // .log("redisratelimiter", Level.FINER);
            return flux.onErrorResume(throwable -> Flux.just(Arrays.asList(1L, -1L)))
                    .reduce(new ArrayList<Long>(), (longs, l) -> {
                        longs.addAll(l);
                        return longs;
                    }) .map(results -> {
                        boolean allowed = results.get(0) == 1L;
                        Long tokensLeft = results.get(1);

                        Response response = new Response(allowed, getHeaders(config, tokensLeft));

                        if (log.isDebugEnabled()) {
                            log.debug("response: " + response);
                        }
                        return response;
                    });
        }
        catch (Exception e) {
            /*
             * We don't want a hard dependency on Redis to allow traffic. Make sure to set
             * an alert so you know if this is happening too much. Stripe's observed
             * failure rate is 0.01%.
             */
            log.error("Error determining if user allowed from redis", e);
        }
        return Mono.just(new Response(true, getHeaders(config, -1L)));
    }

    private LimitConfig getLimitConfig(String routeId) {
        Map<String, LimitConfig> map = new HashMap<>();
        LimitConfig limitConfig = new LimitConfig();
        limitConfig.setRouteId("rateLimit_route");
        Map<String, Config> tokenMap = new HashMap<>();
        Config apiConfig = new Config();
        apiConfig.setBurstCapacity(5);
        apiConfig.setReplenishRate(5);
        
        Config bizConfig = new Config();
        bizConfig.setBurstCapacity(1);
        bizConfig.setReplenishRate(1);
        
        tokenMap.put("/hello/rateLimit", apiConfig);
        tokenMap.put("jieyin", bizConfig);
        limitConfig.setTokenConfig(tokenMap);
        map.put("rateLimit_route", limitConfig);
        return limitConfig;
    }

如上的代码是写死的，但是我们可以根据我们的业务需求设计一个自定义key，自定义令牌桶容量和速率的限流规则。

bean配置和yml配置如下

    @Bean
    @Primary
    public CustomRedisRateLimiter customRedisRateLimiter(ReactiveRedisTemplate<String, String> redisTemplate,
                                             @Qualifier(RedisRateLimiter.REDIS_SCRIPT_NAME) RedisScript<List<Long>> redisScript,
                                             Validator validator) {
        return new CustomRedisRateLimiter(redisTemplate, redisScript, validator);
    }
    
    @Bean
    public RateLimiterGatewayFilterFactory rateLimiterGatewayFilterFactory(CustomRedisRateLimiter customRedisRateLimiter, CustomKeyResolver customKeyResolver) {
        return new RateLimiterGatewayFilterFactory(customRedisRateLimiter, customKeyResolver);
    }

server.port: 8082

spring:
  application:
    name: gateway
  redis:
      host: localhost
      port: 6379
      password: 123456
  cloud:
    gateway:
      routes:
        - id: rateLimit_route
          uri: http://localhost:8000
          order: 0
          predicates:
            - Path=/foo/**
          filters:
            - StripPrefix=1
            - name: RateLimiter

熔断

当下游接口负载很大，或者接口不通等其他原因导致超时，如果接口不熔断的话将会影响到下游接口得不到喘息，网关也会因为超时连接一直挂起，很可能因为一个子系统的问题导致整个系统的雪崩。所以我们的网关需要设计熔断，当因为熔断器打开时，网关将返回一个降级的应答。

熔断配置如下：

server.port: 8082

spring:
  application:
    name: gateway
  redis:
      host: localhost
      port: 6379
      password: 123456
  cloud:
    gateway:
      routes:
        - id: rateLimit_route
          uri: http://localhost:8000
          order: 0
          predicates:
            - Path=/foo/**
          filters:
            - StripPrefix=1
            - name: RateLimiter
            - name: Hystrix
              args:
                name: fallbackcmd
                fallbackUri: forward:/fallback

hystrix.command.fallbackcmd.execution.isolation.thread.timeoutInMilliseconds: 5000

package org.gateway.controller;

import org.gateway.response.Response;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
public class FallbackController {

    @GetMapping("/fallback")
    public Response fallback() {
        Response response = new Response();
        response.setCode("100");
        response.setMessage("服务暂时不可用");
        return response;
    }
}

注意需要设置commandKey的超时时间。其他的hystrix配置请访问Hystrix wiki.

动态配置路由和过滤器

最后我们来看一下如何动态配置路由和过滤器。

定义路由实体

/**
 * Gateway的路由定义模型
 */
public class GatewayRouteDefinition {

    /**
     * 路由的Id
     */
    private String id;

    /**
     * 路由断言集合配置
     */
    private List<GatewayPredicateDefinition> predicates = new ArrayList<>();

    /**
     * 路由过滤器集合配置
     */
    private List<GatewayFilterDefinition> filters = new ArrayList<>();

    /**
     * 路由规则转发的目标uri
     */
    private String uri;

    /**
     * 路由执行的顺序
     */
    private int order = 0;
}

路由断言实体

/**
 * 路由断言定义模型
 */
public class GatewayPredicateDefinition {

    /**
     * 断言对应的Name
     */
    private String name;

    /**
     * 配置的断言规则
     */
    private Map<String, String> args = new LinkedHashMap<>();
}

过滤器实体

/**
 * 过滤器定义模型
 */
public class GatewayFilterDefinition {

    /**
     * Filter Name
     */
    private String name;

    /**
     * 对应的路由规则
     */
    private Map<String, String> args = new LinkedHashMap<>();
}

路由增删改controller

package org.gateway.controller;

import java.net.URI;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import org.gateway.model.GatewayFilterDefinition;
import org.gateway.model.GatewayPredicateDefinition;
import org.gateway.model.GatewayRouteDefinition;
import org.gateway.route.DynamicRouteServiceImpl;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.cloud.gateway.filter.FilterDefinition;
import org.springframework.cloud.gateway.handler.predicate.PredicateDefinition;
import org.springframework.cloud.gateway.route.RouteDefinition;
import org.springframework.util.CollectionUtils;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.util.UriComponentsBuilder;

@RestController
@RequestMapping("/route")
public class RouteController {

    @Autowired
    private DynamicRouteServiceImpl dynamicRouteService;

    /**
     * 增加路由
     * @param gwdefinition
     * @return
     */
    @PostMapping("/add")
    public String add(@RequestBody GatewayRouteDefinition gwdefinition) {
        try {
            RouteDefinition definition = assembleRouteDefinition(gwdefinition);
            return this.dynamicRouteService.add(definition);
        } catch (Exception e) {
            e.printStackTrace();
        }
        return "succss";
    }

    @GetMapping("/delete/{id}")
    public String delete(@PathVariable String id) {
        return this.dynamicRouteService.delete(id);
    }

    @PostMapping("/update")
    public String update(@RequestBody GatewayRouteDefinition gwdefinition) {
        RouteDefinition definition = assembleRouteDefinition(gwdefinition);
        return this.dynamicRouteService.update(definition);
    }

    private RouteDefinition assembleRouteDefinition(GatewayRouteDefinition gwdefinition) {
        RouteDefinition definition = new RouteDefinition();
        List<PredicateDefinition> pdList=new ArrayList<>();
        definition.setId(gwdefinition.getId());
        List<GatewayPredicateDefinition> gatewayPredicateDefinitionList=gwdefinition.getPredicates();
        for (GatewayPredicateDefinition gpDefinition: gatewayPredicateDefinitionList) {
            PredicateDefinition predicate = new PredicateDefinition();
            predicate.setArgs(gpDefinition.getArgs());
            predicate.setName(gpDefinition.getName());
            pdList.add(predicate);
        }
        
        List<GatewayFilterDefinition> gatewayFilterDefinitions = gwdefinition.getFilters();
        List<FilterDefinition> filterList = new ArrayList<>();
        if (!CollectionUtils.isEmpty(gatewayFilterDefinitions)) {
            for (GatewayFilterDefinition gatewayFilterDefinition : gatewayFilterDefinitions) {
                FilterDefinition filterDefinition = new FilterDefinition();
                filterDefinition.setName(gatewayFilterDefinition.getName());
                filterDefinition.setArgs(gatewayFilterDefinition.getArgs());
                filterList.add(filterDefinition);
            }
        }
        definition.setPredicates(pdList);
        definition.setFilters(filterList);
        URI uri = UriComponentsBuilder.fromHttpUrl(gwdefinition.getUri()).build().toUri();
        definition.setUri(uri);
        return definition;
    }
}

动态路由service

package org.gateway.route;

import java.net.URI;
import java.util.Arrays;
import java.util.HashMap;
import java.util.Map;

import org.gateway.model.GatewayPredicateDefinition;
import org.gateway.model.GatewayRouteDefinition;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.cloud.gateway.event.RefreshRoutesEvent;
import org.springframework.cloud.gateway.handler.predicate.PredicateDefinition;
import org.springframework.cloud.gateway.route.RouteDefinition;
import org.springframework.cloud.gateway.route.RouteDefinitionWriter;
import org.springframework.context.ApplicationEventPublisher;
import org.springframework.context.ApplicationEventPublisherAware;
import org.springframework.stereotype.Service;
import org.springframework.web.util.UriComponentsBuilder;

import com.alibaba.fastjson.JSON;

import reactor.core.publisher.Mono;

@Service
public class DynamicRouteServiceImpl implements ApplicationEventPublisherAware {

    @Autowired
    private RouteDefinitionWriter routeDefinitionWriter;

    private ApplicationEventPublisher publisher;


    /**
     * 增加路由
     * @param definition
     * @return
     */
    public String add(RouteDefinition definition) {
        routeDefinitionWriter.save(Mono.just(definition)).subscribe();
        this.publisher.publishEvent(new RefreshRoutesEvent(this));
        return "success";
    }


    /**
     * 更新路由
     * @param definition
     * @return
     */
    public String update(RouteDefinition definition) {
        try {
            this.routeDefinitionWriter.delete(Mono.just(definition.getId()));
        } catch (Exception e) {
            return "update fail,not find route  routeId: "+definition.getId();
        }
        try {
            routeDefinitionWriter.save(Mono.just(definition)).subscribe();
            this.publisher.publishEvent(new RefreshRoutesEvent(this));
            return "success";
        } catch (Exception e) {
            return "update route  fail";
        }


    }
    /**
     * 删除路由
     * @param id
     * @return
     */
    public String delete(String id) {
        try {
            this.routeDefinitionWriter.delete(Mono.just(id));
            return "delete success";
        } catch (Exception e) {
            e.printStackTrace();
            return "delete fail";
        }

    }

    @Override
    public void setApplicationEventPublisher(ApplicationEventPublisher applicationEventPublisher) {
        this.publisher = applicationEventPublisher;
    }
}

 上面 routeDefinitionWriter的实现默认是InMemoryRouteDefinitionRepository，将路由存在内存中，我们可以自己实现一个将路由存在redis中的repository。

this.publisher.publishEvent(new RefreshRoutesEvent(this));则会将CachingRouteLocator中的路由缓存清空。


以上只是springcloud gateway支持的一小部分功能。

虽然springcloud gateway 才发布不久，相关的文档还不是很完善，代码中充满了TODO的地方，react代码友好性低。但是由于它的高性能而且是spring自己的框架，未来取代zuul不是没有可能。

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