K8S下SpringCloud应用无损下线

废话不多说直接上代码，一种2个步骤

步骤一： 添加以下代码到SpringCloud应用中

 

import cn.hutool.extra.spring.SpringUtil;
import com.alibaba.cloud.nacos.registry.NacosAutoServiceRegistration;
import lombok.RequiredArgsConstructor;
import lombok.extern.slf4j.Slf4j;
import org.springframework.boot.autoconfigure.condition.ConditionalOnClass;
import org.springframework.context.ConfigurableApplicationContext;
import org.springframework.http.HttpStatus;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

import javax.servlet.http.HttpServletRequest;
import java.net.InetAddress;
import java.net.UnknownHostException;

/**
 * 使用了nacos注册中心的服务关闭端点配置
 */
@ConditionalOnClass(NacosAutoServiceRegistration.class)
@RestController
@RequestMapping("actuator")
@RequiredArgsConstructor
@Slf4j
public class NacosStopEndpoint {
    private final NacosAutoServiceRegistration nacosAutoServiceRegistration;
    /**
     * 注销服务后关闭应用前等待的时间(毫秒)
     */
    private int waitTime = 30000;


    /**
     * 关闭服务 

     * 只接收localhost发起的请求
     *
     * @param request
     * @return
     */
    @PostMapping("stopService")
    public ResponseEntity stopNacosService(
            HttpServletRequest request) throws UnknownHostException {
        if (!request.getRemoteHost().equalsIgnoreCase("127.0.0.1")) {
            log.warn("非法访问 尝试关闭应用 远程地址[{}]", request.getRemoteHost());
            return ResponseEntity.status(HttpStatus.UNAUTHORIZED).body(false);//非本机访问直接return 防止外部攻击
        }
        new Thread(() -> {
            log.info("Nacos instance has been de-registered");
            nacosAutoServiceRegistration.stop();

            log.info("Waiting {} milliseconds...", waitTime);
            try {
                Thread.sleep(waitTime);
            } catch (InterruptedException e) {
                log.info(Thread.currentThread().getName() + " interrupted!", e);
            }
            log.info("Spring close……");
            ((ConfigurableApplicationContext) SpringUtil.getApplicationContext()).close();
            log.info("Spring closed……");
            System.exit(0);
        }, "Application Closed Thread").start();


        return ResponseEntity.ok(true);
    }
}

步骤二：

配置K8S的工作负载的preStop函数 ， 如下
 

["curl","-X","POST","http://127.0.0.1:8080/actuator/stopService","&&","sleep","30"]

大功告成！从此以后应用下线再也不会丢流量了！