springboot 优雅停机

  最近领导要求我处理公司目前的一个痛点，他们每次发版都是直接将一个进程kill -9 结束进程，然后将新包替换上去，这样会导致一两秒内某些请求服务不可用，而且正在工作的线程会被立即中断，我心里想，那么暴力，还好是家小公司，业务量不会那么大，不然很多用户会奔溃的。

  我一开始跟领导提出使用灰度方案A/B切换来做，就是准备两台环境，然后两套环境进行来回切换，从而实现无缝替换新包，可惜领导不太愿意接受这套方案，很尴尬！

  但是，领导跟我讲

springboot

有提供优雅停机配置，你去研究一下。然后我就去查了相关的资料，确实有这么一个东西。突然，我想到

Dubbo

也有提供优雅停机的配置，于是，我就去看了官网的配置，

Dubbo

优雅停机有个缺陷：

Dubbo

无法做到等待

Dubbo

中的用户线程以外的线程处理完才停机，需要自己对Dubbo的优雅停机功能进行扩展。

  现在我们是基于springboot来实现优雅停机，但是springboot 1.x和2.x配置还是有点区别的，下面来看下springboot 1.x的配置：

springboot 1.x 配置

/**
     * 用于接受shutdown事件
     *
     * @return
     */
    @Bean
    public MyShutdown myShutdown() {
        return new MyShutdown();
    }
    /**
     * 用于注入 connector
     *
     * @return
     */
    @Bean
    public EmbeddedServletContainerCustomizer tomcatCustomizer() {
        return new EmbeddedServletContainerCustomizer() {
            @Override
            public void customize(ConfigurableEmbeddedServletContainer container) {
                if (container instanceof TomcatEmbeddedServletContainerFactory) {
                    ((TomcatEmbeddedServletContainerFactory) container).addConnectorCustomizers(myShutdown());
                }
            }
        };
    }
    private static class MyShutdown implements TomcatConnectorCustomizer, ApplicationListener<ContextClosedEvent> {
        private static final Logger log = LoggerFactory.getLogger(MyShutdown.class);
        private volatile Connector connector;
        private final int waitTime = 100;
        @Override
        public void customize(Connector connector) {
            this.connector = connector;
        }

        @Override
        public void onApplicationEvent(ContextClosedEvent event) {
            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();
                }
            }
        }
    }
           

springboot 2.x 配置

/**
     * 用于接受shutdown事件
     *
     * @return
     */
    @Bean
    public MyShutdown myShutdown() {
        return new MyShutdown();
    }

    /**
     * 用于注入 connector
     *
     * @return
     */
    @Bean
    public WebServerFactoryCustomizer tomcatCustomizer() {
        return (WebServerFactoryCustomizer<ConfigurableWebServerFactory>) container -> {
            if (container instanceof TomcatServletWebServerFactory) {
                ((TomcatServletWebServerFactory) container).addConnectorCustomizers(myShutdown());
            }
        };
    }

    private static class MyShutdown implements TomcatConnectorCustomizer, ApplicationListener<ContextClosedEvent> {
        private static final Logger log = LoggerFactory.getLogger(MyShutdown.class);
        private volatile Connector connector;
        private final int waitTime = 100;
        @Override
        public void customize(Connector connector) {
            this.connector = connector;
        }
        @Override
        public void onApplicationEvent(ContextClosedEvent event) {
            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();
                }
            }
        }
    }