springboot优雅关机的一点想法

boot版本1.5.8

一、原始方法：boot自带的shutdown

引入

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-actuator</artifactId>
        </dependency>

设置

# POST 方法
endpoints:
      shutdown:
           enabled: true
           #禁用密码验证
           sensitive: false

使用post访问/shutdown 可以关闭容器

二、进阶版本

如果有线程池在使用以上的方式/shutdown会报错，同时也会影响线程池中正在进行的任务

针对tomcat的解决办法，建项目nykj-cloud-shutdown

boot版本1.5.8、主类TomcatGracefulShutdown，在容器关闭时通过waitTime，设置容器关闭等待时间

package com.nykj.cloud.shutdown;

import lombok.Data;
import lombok.extern.slf4j.Slf4j;
import org.apache.catalina.connector.Connector;
import org.springframework.boot.context.embedded.tomcat.TomcatConnectorCustomizer;
import org.springframework.context.ApplicationListener;
import org.springframework.context.event.ContextClosedEvent;

import java.time.Duration;
import java.time.LocalDateTime;
import java.util.concurrent.Executor;
import java.util.concurrent.ThreadPoolExecutor;
import java.util.concurrent.TimeUnit;

/**
 * @Auther: 
 * @description:
 * @Date: 18:10 2018/3/6
 */

@Slf4j
@Data
public class TomcatGracefulShutdown implements TomcatConnectorCustomizer,
        ApplicationListener<ContextClosedEvent> {

    private Integer waitTime;

    private volatile Connector connector;

    public TomcatGracefulShutdown(Integer waitTime) {
        this.waitTime = waitTime;
    }

    @Override
    public void customize(Connector connector) {
        this.connector = connector;
    }

    @Override
    public void onApplicationEvent(final ContextClosedEvent event) {
        LocalDateTime startShutdown = LocalDateTime.now();
        LocalDateTime stopShutdown = LocalDateTime.now();
        try {
            log.info("We are now in down mode, please wait " + waitTime + " second(s)...");

            if (connector == null) {
                log.info("We are running unit test ... ");
                Thread.sleep(waitTime * 1000);
                return;
            }
            connector.pause();

            final Executor executor = connector.getProtocolHandler().getExecutor();
            if (executor instanceof ThreadPoolExecutor) {
                log.info("executor is  ThreadPoolExecutor");
                final ThreadPoolExecutor threadPoolExecutor = (ThreadPoolExecutor) executor;
                threadPoolExecutor.shutdown();
                if (!threadPoolExecutor.awaitTermination(waitTime, TimeUnit.SECONDS)) {
                    log.warn("Tomcat thread pool did not shut down gracefully within " + waitTime + " second(s). Proceeding with force shutdown");
                } else {
                    log.debug("Tomcat thread pool is empty, we stop now");
                }
            }
            stopShutdown = LocalDateTime.now();
        } catch (final InterruptedException ex) {
            log.error("The await termination has been interrupted : " + ex.getMessage());
            Thread.currentThread().interrupt();
        } finally {
            final long seconds = Duration.between(startShutdown, stopShutdown).getSeconds();
            log.info("Shutdown performed in " + seconds + " second(s)");
        }
    }
}

将主类初始化到spring 容器，默认waittime是30秒

package com.nykj.cloud.shutdown;

import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

/**
 * @Auther: 
 * @description:
 * @Date: 11:47 2018/3/12
 */
@Configuration
@Slf4j
public class TomcatGracefulShutdownAutoConfiguration {

    @Value("${nykj.tomcat.shutdown.waitTime:30}")
    private Integer waitTime;

    @Bean
    public TomcatGracefulShutdown tomcatGracefulShutdown() {
        TomcatGracefulShutdown tomcatGracefulShutdown = new TomcatGracefulShutdown(waitTime);
        log.info("------------register tomcat graceful shutdown ... " + waitTime);
        return tomcatGracefulShutdown;
    }
}

设置spring.factories

org.springframework.boot.autoconfigure.EnableAutoConfiguration=\
 com.nykj.cloud.shutdown.TomcatGracefulShutdownAutoConfiguration

在微服务pom中引入，在服务中根据线程池执行时间设置关闭容器的等待时间 nykj.tomcat.shutdown.waitTime: 100

        <dependency>
            <groupId>com.nykj.cloudutils</groupId>
            <artifactId>nykj-cloud-shutdown</artifactId>
            <version>1.0.0-SNAPSHOT</version>
        </dependency>

使用/shutdown调用，先从注册中心下线，指定时间后关闭

三、其他版本

   可以让服务先下线，此时服务还是存活的，可以从容处理完线程内任务。

   1、DiscoveryManager.getInstance().shutdownComponent()    此方法已过时。

   2、也可以在/health借口上做文章、eureka通过健康检查接口来判断服务是否健康，可以追加检查项，让服务处于down的状态。

如果有其他更优雅的方式欢迎沟通评论。

可以考虑把下线和关闭应用作为两个功能，集成到后台管理平台，或者分布式配置中心，或者容器管理工具