spring cloud gateway通过nacos实现动态路由

---
title: Spring Cloud Gateway通过nacos实现动态路由
date: 2019-07-15 08:03:34
categories:
- Nacos
- Spring Cloud Gateway
tags:
- nacos
- Gateway
- 动态路由
---

这两天搭了下Spring Cloud Gateway，在配置文件里配置路由，可以成功转发。但是现阶段Spring Cloud Gateway用配置文件的方式不支持动态路由，而网关作为所有访问的入口，必须保证高可用，动态路由能让网关服务不重启动态改变路由。实现方法比较简单，但是中间也踩了一些坑。

1.增加一个类，代码如下：

package com.zp.gateway;

import com.alibaba.fastjson.JSONObject;
import com.alibaba.nacos.api.NacosFactory;
import com.alibaba.nacos.api.config.ConfigService;
import com.alibaba.nacos.api.config.listener.Listener;
import com.alibaba.nacos.api.exception.NacosException;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.cloud.gateway.event.RefreshRoutesEvent;
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.Component;
import reactor.core.publisher.Mono;

import javax.annotation.PostConstruct;
import java.util.ArrayList;
import java.util.List;
import java.util.concurrent.Executor;

@Component
public class NacosDynamicRouteService implements ApplicationEventPublisherAware {
 
    private String dataId = "gateway-router";
 
    private String group = "test2";
 
    @Value("${spring.cloud.nacos.config.server-addr}")
    private String serverAddr;
 
    @Autowired
    private RouteDefinitionWriter routeDefinitionWriter;
 
    private ApplicationEventPublisher applicationEventPublisher;
 
    private static final List<String> ROUTE_LIST = new ArrayList<>();
 
    @PostConstruct
    public void dynamicRouteByNacosListener() {
        try {
            ConfigService configService = NacosFactory.createConfigService(serverAddr);
            String config = configService.getConfig(dataId, group, 5000);
            System.out.println(config);
            configService.addListener(dataId, group, new Listener() {
                @Override
                public void receiveConfigInfo(String configInfo) {
                    clearRoute();
                    try {
                        List<RouteDefinition> gatewayRouteDefinitions = JSONObject.parseArray(configInfo, RouteDefinition.class);
                        for (RouteDefinition routeDefinition : gatewayRouteDefinitions) {
                            addRoute(routeDefinition);
                        }
                        publish();
                    } catch (Exception e) {
                        e.printStackTrace();
                    }
                }
 
                @Override
                public Executor getExecutor() {
                    return null;
                }
            });
        } catch (NacosException e) {
            e.printStackTrace();
        }
    }
 
    private void clearRoute() {
        for(String id : ROUTE_LIST) {
            this.routeDefinitionWriter.delete(Mono.just(id)).subscribe();
        }
        ROUTE_LIST.clear();
    }
 
    private void addRoute(RouteDefinition definition) {
        try {
            routeDefinitionWriter.save(Mono.just(definition)).subscribe();
            ROUTE_LIST.add(definition.getId());
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
 
    private void publish() {
        this.applicationEventPublisher.publishEvent(new RefreshRoutesEvent(this.routeDefinitionWriter));
    }
 
    @Override
    public void setApplicationEventPublisher(ApplicationEventPublisher applicationEventPublisher) {
        this.applicationEventPublisher = applicationEventPublisher;
    }
}

2.将原本配置文件里的静态路由删掉。

3.在nacos的管理界面里新增一个配置，DataId和Group和上面代码里保持 一致，分别为gateway-router和test2。

配置格式选为json，内容为

[{
    "filters":[{
       "args":{
           "parts": "1"
       },
       "name": "StripPrefix"
   }],
   "id": "provider12",
   "order": 0,
   "predicates":[{
       "args":{
           "pattern": "/consumer115/**"
       },
       "name": "Path"
   }],
   "uri": "lb://consumer" 
}]

注意：这里的filters里的写法请注意：name为属性名，parts为属性值，这个写法等价于配置文件里的StripPrefix=1

而StripPrefix=1的意思是，将匹配的前缀去掉。上面的json配置中，当请求为/consumer115/name时，将转发给服务名为consumer的/name接口

如果不加StripPrefix=1，则会转发给consumer的/consumer115/name接口