关于springboot:spring项目优雅停机

        最近，公司我的项目优化重构，为了我的项目能够无缝高低线，如丝般顺滑，思考到增加优雅停机性能。优雅停机蕴含线程池、音讯、数据库、服务下线。

        jvm 有钩子函数在收到 kill 命令后会执行回掉，能够应用这个实现优雅下线。简略介绍一下 kill 命令。- 2 相似于 ctrl+c，kill -15 服务失常下线会触发 jvm 钩子函数。kill - 9 零碎内核间接杀死，不会触发钩子函数。

优雅下线波及到 bean 的生命周期销毁。ContextClosedEvent 和 @PreDestroy 和周期和 DisposableBean 参考链接
https://blog.csdn.net/qq_4384…

线程池、mq、db 等都在 spring 的 bean 销毁之前下线, 留神下线程序。例子：

 private ThreadPoolExecutor executor;

    @Bean
    @Primary
    public ThreadPoolExecutor asyncServiceExecutor() {executor = new ThreadPoolExecutor(5, 20, 60L, TimeUnit.SECONDS, new LinkedBlockingQueue<>(1000), new ThreadPoolExecutor.CallerRunsPolicy());
        return executor;
    }

    @PreDestroy
    public void destroyThreadPool() {if (!executor.isTerminated()){executor.shutdown();
            try {executor.awaitTermination(10, TimeUnit.SECONDS);
            } catch (InterruptedException e) {e.printStackTrace();
                executor.shutdownNow();}
        }
        log.info("ThreadPoolExecutor destroyed !");
    }

dubbo 下线

dubbo 默认开启了优雅停机。下线分为从注册核心下线，敞开协定
2.7 之后源码如下：ShutdownHookListener，继承 Spring ApplicationListener 接口，用以监听 Spring 相干事件。这里 ShutdownHookListener 仅仅监听 Spring 敞开事件，当 Spring 开始敞开，将会触发 ShutdownHookListener 外部逻辑

public class SpringExtensionFactory implements ExtensionFactory {private static final Logger logger = LoggerFactory.getLogger(SpringExtensionFactory.class);

    private static final Set<ApplicationContext> CONTEXTS = new ConcurrentHashSet<ApplicationContext>();
    private static final ApplicationListener SHUTDOWN_HOOK_LISTENER = new ShutdownHookListener();

    public static void addApplicationContext(ApplicationContext context) {CONTEXTS.add(context);
        if (context instanceof ConfigurableApplicationContext) {
            // 注册 ShutdownHook
            ((ConfigurableApplicationContext) context).registerShutdownHook();
            // 勾销 AbstractConfig 注册的 ShutdownHook 事件
            DubboShutdownHook.getDubboShutdownHook().unregister();
        }
        BeanFactoryUtils.addApplicationListener(context, SHUTDOWN_HOOK_LISTENER);
    }
    // 继承 ApplicationListener，这个监听器将会监听容器敞开事件
    private static class ShutdownHookListener implements ApplicationListener {
        @Override
        public void onApplicationEvent(ApplicationEvent event) {if (event instanceof ContextClosedEvent) {DubboShutdownHook shutdownHook = DubboShutdownHook.getDubboShutdownHook();
                shutdownHook.doDestroy();}
        }
    }
}
通过配置 dubbo.application.shutwait=30s 能够设置 dubbo 等待时间 

springboot 下线

        相熟介绍 springboot 优雅停机，在 Springboot2.3 之前须要本人实现优雅停机。2.3 后本人实现了优雅停机。

springboot2.3 之前的实现形式。

1、创立 SafetyShutDownConfig 类实现 TomcatConnectorCustomizer,ApplicationListener<ContextClosedEvent> 接口即可，kill - 2 和 kill -15 就能够进行测试

@Slf4j
@Configuration
public class SafetyShutDownConfig implements TomcatConnectorCustomizer, ApplicationListener<ContextClosedEvent> {

    private volatile Connector connector;
    private final int waitTime = 30;

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

    @Override
    public void onApplicationEvent(ContextClosedEvent contextClosedEvent) {this.connector.pause();
        Executor executor = this.connector.getProtocolHandler().getExecutor();
        if (executor instanceof ThreadPoolExecutor) {
            try {ThreadPoolExecutor threadPoolExecutor = (ThreadPoolExecutor) executor;
                threadPoolExecutor.shutdown();
                if (!threadPoolExecutor.awaitTermination(waitTime, TimeUnit.SECONDS)) {log.warn("Tomcat thread pool did not shut down gracefully within" + waitTime + "seconds. Proceeding with forceful shutdown");
                }
            } catch (InterruptedException ex) {Thread.currentThread().interrupt();}
        }
    }
}

springboot2.3 之后的实现

1、在配置文件中开启就能够
#开启优雅停机
server.shutdown=graceful
#优雅停机最大等待时间
spring.lifecycle.timeout-per-shutdown-phase=30s