物联网架构成长之路(54)-基于Nacos+Gateway实现动态路由

0. 前言
　　本来就负责一些小事情，但是还是要搞事情。把一个小项目切分成微服务，练练手。
　　主要是以Nacos为配置中心，实现Spring Cloud GateWay的动态路由功能。然后在实现日志、鉴权等功能。动态路由，就是在Spring Cloud Gateway启动的时候，将路由配置和规则加载到内存里，但是通过集成Nacos，增加一个监听器，就可以在不重启网关，实现对应路由的配置和规则更新。实现动态路由。

1. 集成Nacos和Spring Cloud GateWay
　　pom.xml

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-actuator</artifactId>
        </dependency>
        
        <!-- Gateway Nacos Sentinel 网关路由、配置中心、服务器注册中心、流量控制、熔断降级 -->
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-gateway</artifactId>
        </dependency>
        <dependency>
            <groupId>com.alibaba.cloud</groupId>
            <artifactId>spring-cloud-starter-alibaba-nacos-config</artifactId>
        </dependency>
        <dependency>
            <groupId>com.alibaba.cloud</groupId>
            <artifactId>spring-cloud-starter-alibaba-nacos-discovery</artifactId>
        </dependency>
        <dependency>
            <groupId>com.alibaba.cloud</groupId>
            <artifactId>spring-cloud-starter-alibaba-sentinel</artifactId>
        </dependency>

　　bootstrap.properties

#dev/test/prod
spring.profiles.active=dev
#nacos
spring.cloud.nacos.server-addr=127.0.0.1:8848
spring.cloud.nacos.config.namespace=0e152861-1efa-62ea-9125-e569abc29691
spring.cloud.nacos.discovery.namespace=0e152861-1efa-62ea-9125-e569abc29691
spring.cloud.nacos.config.prefix=xxxx-story-gateway
spring.cloud.nacos.config.file-extension=properties

2. 配置动态路由到Nacos

　　具体配置路由信息

[{
    "id": "xxxx-story-res",
    "order": 1,
    "predicates": [{
        "args": {
            "pattern": "/res/v1/**"
        },
        "name": "Path"
    }],
    "uri": "lb://xxxx-story-res"
},{
    "id": "xxxx-story-aiml",
    "order": 2,
    "predicates": [{
        "args": {
            "pattern": "/aiml/v1/**"
        },
        "name": "Path"
    }],
    "uri": "lb://xxxx-story-aiml"
}]

3. Java代码里增加一个BeanConfig就可以实现
　　DynamicRouteConfig.java

package com.wunaozai.demo.story.gateway.config;

import java.util.ArrayList;
import java.util.List;
import java.util.Properties;
import java.util.concurrent.Executor;

import javax.annotation.PostConstruct;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
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.Service;

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 reactor.core.publisher.Mono;

/**
 * 动态路由，可以通过获取Bean才做该类，提供增删改查已经发布功能
 * @author wunaozai
 * @Date 2020-03-16
 */
@Service
public class DynamicRouteConfig implements ApplicationEventPublisherAware {

    private static final Logger log = LoggerFactory.getLogger(DynamicRouteConfig.class);

    @Autowired
    private RouteDefinitionWriter routedefinitionWriter;
    
    private ApplicationEventPublisher publisher;
    
    private String dataId = "gateway-router.properties";
    private String group = "DEFAULT_GROUP";
    @Value("${spring.cloud.nacos.server-addr}")
    private String serverAddr;
    @Value("${spring.cloud.nacos.config.namespace}")
    private String namespace;
    
    private static final List<String> ROUTE_LIST = new ArrayList<>();
    
    @PostConstruct
    public void dynamicRouteByNacosListener() {
        try {
            Properties prop = new Properties();
            prop.put("serverAddr", serverAddr);
            prop.put("namespace", namespace);
            ConfigService config = NacosFactory.createConfigService(prop);
            String content = config.getConfig(dataId, group, 5000);
            publisher(content);
            config.addListener(dataId, group, new Listener() {
                @Override
                public void receiveConfigInfo(String config) {
                    publisher(config);
                }
                @Override
                public Executor getExecutor() {
                    return null;
                }
            });
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
    
    /**
     * 增加路由
     * @param def
     * @return
     */
    public Boolean addRoute(RouteDefinition def) {
        try {
            routedefinitionWriter.save(Mono.just(def)).subscribe();
            ROUTE_LIST.add(def.getId());    
        } catch (Exception e) {
            e.printStackTrace();
        }
        return true;
    }
    /**
     * 删除路由
     * @return
     */
    public Boolean clearRoute() {
        for(String id: ROUTE_LIST) {
            routedefinitionWriter.delete(Mono.just(id)).subscribe();
        }
        ROUTE_LIST.clear();
        return false;
    }
    /**
     * 发布路由
     */
    private void publisher(String config) {
        clearRoute();
        try {
            log.info("重新更新动态路由");
            List<RouteDefinition> gateway = JSONObject.parseArray(config, RouteDefinition.class);
            for(RouteDefinition route: gateway) {
                addRoute(route);
            }
            publisher.publishEvent(new RefreshRoutesEvent(this.routedefinitionWriter));
        } catch (Exception e) {
            e.printStackTrace();
        }
        
    }
    
    @Override
    public void setApplicationEventPublisher(ApplicationEventPublisher app) {
        publisher = app;
    }

}

　　请求不同的URL转发到不同的服务器上
　　/res/v1/**
　　/aiml/v1/**

　　至此就完成简单的动态路由功能了。我们修改nacos上的 gateway-router.properties ，程序会自动执行 DynamicRouteConfig.java 里面的 receiveConfigInfo 方法。动态加载配置，动态发布更新路由。
　　用到Gateway，一般是用来实现鉴权，限流，熔断，网关路由，日志等功能。这一篇介绍了网关路由功能，由于SpringBoot默认就有日志功能，这里就不展开说。下一篇将介绍集成Sentinel的限流和熔断。再下一篇是介绍基于SpringBoot Secret 的Oauth2.0鉴权，结合到该项目中。

参考资料：
　　https://blog.csdn.net/zhangchangbin123/article/details/89310353

本文地址：https://www.cnblogs.com/wunaozai/p/12512753.html
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