Spring Gateway集成 Nacos注册中心不能够发现服务的问题解决

墨蓝 2022-09-15 05:42 102阅读 0赞

# 一、问题描述 #

我们现在是在用Nacos替换Eureka，原来Eureka和Spring gateway运行正常，可以通过Spring gateway调用注册到Eureka中的服务。

当前Spring cloud的版本是Hoxton.SR8，Nacos discovery的版本为0.9.0.RELEASE，使用的Nacos版本为2.0.3。

Nacos替换Eureka改动的地方如下：

１、去掉POM中Eureka的引入；

２、去掉主类中引入的@EnableEurekaClient注解；

３、引入Nacos依赖：

<dependency>
      <groupId>org.springframework.cloud</groupId>
      <artifactId>spring-cloud-starter-alibaba-nacos-discovery</artifactId>
      <version>0.9.0.RELEASE</version>
      <exclusions>
        <exclusion>
            <groupId>com.alibaba.nacos</groupId>
            <artifactId>nacos-client</artifactId>
        </exclusion>
        <exclusion>
         <groupId>org.springframework.cloud</groupId>
         <artifactId>spring-cloud-starter-netflix-ribbon</artifactId>
        </exclusion>
      </exclusions>
    </dependency>
    <dependency>
      <groupId>com.alibaba.nacos</groupId>
      <artifactId>nacos-client</artifactId>
      <version>2.0.3</version>
    </dependency>

４、引入spring-cloud-loadbalancer：

<dependency>
    	<groupId>org.springframework.cloud</groupId>
    	<artifactId>spring-cloud-loadbalancer</artifactId>
    </dependency>

５、spring-cloud-starter-openfeign中exclude掉ribbon的依赖：

<dependency>
        <groupId>org.springframework.cloud</groupId>
        <artifactId>spring-cloud-starter-openfeign</artifactId>
        <exclusions>
            <exclusion>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-netflix-ribbon</artifactId>
            </exclusion>
        </exclusions>
    </dependency>

６、application.yml中禁用nacos的ribbon：

ribbon:
      nacos:
        enabled: false

现在的现象：

*  Spring gateway启动不报错；
 *  gateway也可以正常注册到Nacos；
 *  通过打断点到NacosDiscoveryClientAutoConfiguration，NacosDiscoveryClient会被初使化，但是调用时不会调用NacosDiscoveryClient.getInstances(String)获取被调用应用的Provider，会报类似下面的接口404错误：

\{"msg":"/user-service/user/getByToken","result":404,"data":null\}

其中user-service为注册到Nacos上面的服务名称，但是就是不能够被调用到。

*  Spring gateway的注册中心切换为Eureka，再次调用服务时，Eureka的CompositeDiscoveryClient.getInstances(String)方法就会被调用。

# 二、问题分析 #

前面走了一些弯路，也花了一些时间，最后想到的是与Eureka注册中心进行对比调试分析，下面例出关键的分析步骤。

Debug断点打到DiscoveryClientRouteDefinitionLocator两个构造函数上，只有参数是ReactiveDiscoveryClient的构造函数被加载：

![watermark_type_ZHJvaWRzYW5zZmFsbGJhY2s_shadow_50_text_Q1NETiBA5Yav56uL5b2s_size_20_color_FFFFFF_t_70_g_se_x_16][]

继续跟踪到ReactiveCompositeDiscoveryClient.getServices()方法：

![watermark_type_ZHJvaWRzYW5zZmFsbGJhY2s_shadow_50_text_Q1NETiBA5Yav56uL5b2s_size_20_color_FFFFFF_t_70_g_se_x_16 1][]

发现数组变量discoveryClients包含了两个实现，如下图所示：

![watermark_type_ZHJvaWRzYW5zZmFsbGJhY2s_shadow_50_text_Q1NETiBA5Yav56uL5b2s_size_20_color_FFFFFF_t_70_g_se_x_16 2][]

其中有一个是EurekaReactiveDiscoveryClient，那在使用Nacos时就应该包含一个针对Nacos实现的ReactiveDiscoveryClient，于是切换为Nacos分支调试。

但是调试发现数组变量discoveryClients并没有包含针对Nacos实现的ReactiveDiscoveryClient：

![watermark_type_ZHJvaWRzYW5zZmFsbGJhY2s_shadow_50_text_Q1NETiBA5Yav56uL5b2s_size_20_color_FFFFFF_t_70_g_se_x_16 3][]

于是参考EurekaReactiveDiscoveryClient以及NacosDiscoveryClient，立即就写了NacosReactiveDiscoveryClient：

import java.util.ArrayList;
    import java.util.Collections;
    import java.util.HashMap;
    import java.util.List;
    import java.util.Map;
    
    import org.springframework.cloud.alibaba.nacos.NacosDiscoveryProperties;
    import org.springframework.cloud.alibaba.nacos.NacosServiceInstance;
    import org.springframework.cloud.client.ServiceInstance;
    import org.springframework.cloud.client.discovery.ReactiveDiscoveryClient;
    
    import com.alibaba.nacos.api.naming.pojo.Instance;
    import com.alibaba.nacos.api.naming.pojo.ListView;
    
    import lombok.extern.slf4j.Slf4j;
    import reactor.core.publisher.Flux;
    /**
     * 
     * @author fenglibin
     *
     */
    @Slf4j
    public class NacosReactiveDiscoveryClient implements ReactiveDiscoveryClient {
    
    	public static final String DESCRIPTION = "Spring Cloud Nacos Reactive Discovery Client";
    
    	private NacosDiscoveryProperties discoveryProperties;
    
    	public NacosReactiveDiscoveryClient(NacosDiscoveryProperties discoveryProperties) {
    		this.discoveryProperties = discoveryProperties;
    	}
    
    	@Override
    	public String description() {
    		return DESCRIPTION;
    	}
    
    	@Override
    	public Flux<ServiceInstance> getInstances(String serviceId) {
    		try {
    			List<Instance> instances = discoveryProperties.namingServiceInstance().selectInstances(serviceId, true);
    
    			return Flux.fromStream(hostToServiceInstanceList(instances, serviceId).stream());
    		} catch (Exception e) {
    			throw new RuntimeException("Can not get hosts from nacos server. serviceId: " + serviceId, e);
    		}
    	}
    
    	@Override
    	public Flux<String> getServices() {
    		try {
    			ListView<String> services = discoveryProperties.namingServiceInstance().getServicesOfServer(1,
    					Integer.MAX_VALUE);
    
    			return Flux.fromStream(services.getData().parallelStream());
    		} catch (Exception e) {
    			log.error("get service name from nacos server fail,", e);
    			return Flux.fromStream(Collections.<String>emptyList().stream());
    		}
    	}
    
    	private static ServiceInstance hostToServiceInstance(Instance instance, String serviceId) {
    		NacosServiceInstance nacosServiceInstance = new NacosServiceInstance();
    		nacosServiceInstance.setHost(instance.getIp());
    		nacosServiceInstance.setPort(instance.getPort());
    		nacosServiceInstance.setServiceId(serviceId);
    
    		Map<String, String> metadata = new HashMap<>();
    		metadata.put("nacos.instanceId", instance.getInstanceId());
    		metadata.put("nacos.weight", instance.getWeight() + "");
    		metadata.put("nacos.healthy", instance.isHealthy() + "");
    		metadata.put("nacos.cluster", instance.getClusterName() + "");
    		metadata.putAll(instance.getMetadata());
    		nacosServiceInstance.setMetadata(metadata);
    
    		if (metadata.containsKey("secure")) {
    			boolean secure = Boolean.parseBoolean(metadata.get("secure"));
    			nacosServiceInstance.setSecure(secure);
    		}
    		return nacosServiceInstance;
    	}
    
    	private static List<ServiceInstance> hostToServiceInstanceList(List<Instance> instances, String serviceId) {
    		List<ServiceInstance> result = new ArrayList<>(instances.size());
    		for (Instance instance : instances) {
    			result.add(hostToServiceInstance(instance, serviceId));
    		}
    		return result;
    	}
    
    }

或者集成如下starter：

<dependency>
            <groupId>com.eeeffff</groupId>
            <artifactId>nacos-reactive-discovery-client</artifactId>
            <version>1.0.0</version>
        </dependency>

并在启动时创建Bean：

![watermark_type_ZHJvaWRzYW5zZmFsbGJhY2s_shadow_50_text_Q1NETiBA5Yav56uL5b2s_size_20_color_FFFFFF_t_70_g_se_x_16 4][]

再次启动调试就可以看到数组变量discoveryClients中有NacosReactiveDiscoveryClient了：

![watermark_type_ZHJvaWRzYW5zZmFsbGJhY2s_shadow_50_text_Q1NETiBA5Yav56uL5b2s_size_20_color_FFFFFF_t_70_g_se_x_16 5][]

再次通过网关请求服务，就可以正常调用成功了。

感觉Nacos的怪问题都让我给碰上了！

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