1. 背景

发布版本的时候存在如下情况导致调用失败

service_call.jpg

时刻	动作
T1	服务A从nacos获取服务B实例1
T2	服务A负载均衡选择到实例1
T3	服务B实例1下线
T4	服务A调用服务B 实例1

2. 解决方法

1. 确保服务A拿到的实例一定是正常的

1. 服务B实例先从nacos下线。
2. 等待数秒后服务A知晓服务B实例下线。
3. 服务A调用服务B正常的实例。

2. 重试

3. 核心代码

代码仓库nacos-deregister-instance-actuator

1. 定义Endpoint

package com.daxiyan.nacos;

import com.alibaba.cloud.nacos.NacosDiscoveryProperties;
import com.alibaba.nacos.api.exception.NacosException;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.actuate.endpoint.annotation.Endpoint;
import org.springframework.boot.actuate.endpoint.annotation.ReadOperation;


@Endpoint(id = "nacos-deregister-instance")
public class NacosDeRegisterInstanceEndpoint {

    public static Logger logger = LoggerFactory.getLogger(NacosDeRegisterInstanceEndpoint.class);

    @Autowired
    private NacosDiscoveryProperties nacosDiscoveryProperties;

    public NacosDeRegisterInstanceEndpoint(NacosDiscoveryProperties nacosDiscoveryProperties) {
        this.nacosDiscoveryProperties = nacosDiscoveryProperties;
    }

    @ReadOperation
    public String deregisterInstance() {
        String serviceName = nacosDiscoveryProperties.getService();
        String groupName = nacosDiscoveryProperties.getGroup();
        String clusterName = nacosDiscoveryProperties.getClusterName();
        String ip = nacosDiscoveryProperties.getIp();
        int port = nacosDiscoveryProperties.getPort();
        logger.info("deregister from nacos, serviceName:{}, groupName:{}, clusterName:{}, ip:{}, port:{}", serviceName, groupName, clusterName, ip, port);
        try {
            nacosDiscoveryProperties.namingServiceInstance().deregisterInstance(serviceName, groupName, ip, port, clusterName);
        } catch (NacosException e) {
            logger.error("deregister from nacos error", e);
            return "error";
        }
        return "success";
    }

}

2. 自动装配类

package com.daxiyan.nacos;

import com.alibaba.cloud.nacos.NacosDiscoveryProperties;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.actuate.endpoint.annotation.Endpoint;
import org.springframework.boot.autoconfigure.condition.ConditionalOnBean;
import org.springframework.boot.autoconfigure.condition.ConditionalOnClass;
import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
import org.springframework.context.annotation.Bean;


@ConditionalOnClass(Endpoint.class)
@ConditionalOnBean(type = "com.alibaba.cloud.nacos.NacosDiscoveryProperties")
public class NacosDeRegisterInstanceEndpointAutoConfiguration {

    @Autowired
    private NacosDiscoveryProperties nacosDiscoveryProperties;


    @ConditionalOnMissingBean
    @Bean
    public NacosDeRegisterInstanceEndpoint nacosDeRegisterEndpoint() {
        return new NacosDeRegisterInstanceEndpoint(nacosDiscoveryProperties);
    }


}

3. META-INT/spring.factories

org.springframework.boot.autoconfigure.EnableAutoConfiguration=\
com.daxiyan.nacos.NacosDeRegisterInstanceEndpointAutoConfiguration

4.使用

本地安装jar

mvn install

maven pom添加依赖

maven pom.xml

<dependency>
   <groupId>com.daxiyan.nacos</groupId>
   <artifactId>nacos-deregister-instance-actuator</artifactId>
   <version>1.0-SNAPSHOT</version>
</dependency>

引入冲突解决

排序依赖

     <dependency>
            <groupId>com.daxiyan.nacos</groupId>
            <artifactId>nacos-deregister-instance-actuator</artifactId>
            <version>1.0-SNAPSHOT</version>
            <exclusions>
                <exclusion>
                    <groupId>org.springframework.boot</groupId>
                    <artifactId>spring-boot-starter-actuator</artifactId>
                </exclusion>
                <exclusion>
                    <groupId>com.alibaba.cloud</groupId>
                    <artifactId>spring-cloud-starter-alibaba-nacos-discovery</artifactId>
                </exclusion>
            </exclusions>
        </dependency>

触发

bootstrap.yml 配置

#监控配置
management:
  endpoints:
    web:
      base-path: "/actuator"
      exposure:
        include: "*"
  endpoint:
    shutdown:
      enabled: true
  server:
    port: 9090

curl  http://localhost:{management.server.port}/actuator/nacos-deregister-instance

其他

搜索spring cloud应该提供这种通用的服务下线功能，后来的确看到了
org.springframework.cloud.client.serviceregistry.endpoint.ServiceRegistryEndpoint

package org.springframework.cloud.client.serviceregistry.endpoint;
import org.springframework.boot.actuate.endpoint.annotation.Endpoint;
import org.springframework.boot.actuate.endpoint.annotation.ReadOperation;
import org.springframework.boot.actuate.endpoint.annotation.WriteOperation;
import org.springframework.cloud.client.serviceregistry.Registration;
import org.springframework.cloud.client.serviceregistry.ServiceRegistry;
import org.springframework.http.HttpStatus;
import org.springframework.http.ResponseEntity;
import org.springframework.util.Assert;
/**
 * Endpoint to display and set the service instance status using the ServiceRegistry.
 *
 * @author Spencer Gibb
 */
@SuppressWarnings("unchecked")
@Endpoint(id = "service-registry")
public class ServiceRegistryEndpoint {

    private final ServiceRegistry serviceRegistry;

    private Registration registration;

    public ServiceRegistryEndpoint(ServiceRegistry<?> serviceRegistry) {
        this.serviceRegistry = serviceRegistry;
    }

    public void setRegistration(Registration registration) {
        this.registration = registration;
    }

    @WriteOperation
    public ResponseEntity<?> setStatus(String status) {
        Assert.notNull(status, "status may not by null");

        if (this.registration == null) {
            return ResponseEntity.status(HttpStatus.NOT_FOUND)
                    .body("no registration found");
        }

        this.serviceRegistry.setStatus(this.registration, status);
        return ResponseEntity.ok().build();
    }

    @ReadOperation
    public ResponseEntity getStatus() {
        if (this.registration == null) {
            return ResponseEntity.status(HttpStatus.NOT_FOUND)
                    .body("no registration found");
        }

        return ResponseEntity.ok()
                .body(this.serviceRegistry.getStatus(this.registration));
    }
}

调用

curl -i -H "Content-Type: application/json" -X POST -d '{"status":"DOWN"}' http://localhost:9090/actuator/service-registry