Graceful shutdown 应用

Graceful shutdown说明

Graceful shutdown is supported with all four embedded web servers (Jetty, Reactor Netty, Tomcat, and Undertow) and with both reactive and servlet-based web applications. It occurs as part of closing the application context and is performed in the earliest phase of stopping SmartLifecycle beans. This stop processing uses a timeout which provides a grace period during which existing requests will be allowed to complete but no new requests will be permitted. The exact way in which new requests are not permitted varies depending on the web server that is being used. Jetty, Reactor Netty, and Tomcat will stop accepting requests at the network layer. Undertow will accept requests but respond immediately with a service unavailable (503) response.

版本要求

对Tomcat有版本要求，不能低于9.0.33

 Graceful shutdown with Tomcat requires Tomcat 9.0.33 or later. 

配置方式

# 配置启用graceful
server.shutdown=graceful
# 配置超时等待活跃请求的时间，默认30s
spring.lifecycle.timeout-per-shutdown-phase=30s 

特别说明

监控的是SIGTERM信号，SIGTERM是Linux提供的一种优雅关闭服务的方式，通过发出一个软件终止的信号来给应用程序一个缓冲的时间，相对于SIGKILL这种，就会直接杀掉进程。

Using graceful shutdown with your IDE may not work properly if it does not send a proper SIGTERM signal. See the documentation of your IDE for more details.

验证

只需简单配置后，即可使用，启动服务，发起请求。

@Slf4j
@RestController
public class TestController {

    @RequestMapping("/activeRequest")
    public void activeRequest() throws InterruptedException {
        log.info("【请求执行中】");
        /**
         * spring.lifecycle.timeout-per-shutdown-phase=30s
         * 配置为等待30秒，因此在执行改方法后的10秒内，如果停止了web服务，依然会等待改方法执行完毕
         */
        Thread.sleep(10000);
        log.info("【请求执行结束】");
    }
    
}

输出日志中，可以看到，当发起停止服务时，打印了Commencing graceful shutdown. Waiting for active requests to complete，表示开始等待活跃的请求执行结束。

当执行结束后，打印Graceful shutdown complete，开始关闭其他相关资源。

2023-03-18 10:31:41.582  INFO 18056 --- [nio-8080-exec-1] c.w.controller.安全关闭WEB服务.TestController  : 【请求执行中】
Disconnected from the target VM, address: '127.0.0.1:51695', transport: 'socket'
2023-03-18 10:31:45.158  INFO 18056 --- [extShutdownHook] o.s.b.w.e.tomcat.GracefulShutdown        : Commencing graceful shutdown. Waiting for active requests to complete
2023-03-18 10:31:51.593  INFO 18056 --- [nio-8080-exec-1] c.w.controller.安全关闭WEB服务.TestController  : 【请求执行结束】耗时：10007毫秒
2023-03-18 10:31:51.656  INFO 18056 --- [tomcat-shutdown] o.s.b.w.e.tomcat.GracefulShutdown        : Graceful shutdown complete
2023-03-18 10:31:51.664  INFO 18056 --- [extShutdownHook] o.s.s.concurrent.ThreadPoolTaskExecutor  : Shutting down ExecutorService 'applicationTaskExecutor'
2023-03-18 10:31:51.665  INFO 18056 --- [extShutdownHook] com.alibaba.druid.pool.DruidDataSource   : {dataSource-1} closing ...
2023-03-18 10:31:51.677  INFO 18056 --- [extShutdownHook] com.alibaba.druid.pool.DruidDataSource   : {dataSource-1} closed

如果把spring.lifecycle.timeout-per-shutdown-phase=10s 配置改为10秒，而activeRequest方法要执行20秒

@RequestMapping("/activeRequest")
public void activeRequest() throws InterruptedException {
    log.info("【请求执行中】");
    Stopwatch started = Stopwatch.createStarted();
    /**
     * spring.lifecycle.timeout-per-shutdown-phase=10s
     * 配置为等待10秒，因此改方法最终不会执行完成。
     */
    Thread.sleep(20000);
    log.info("【请求执行结束】耗时：" + started.elapsed(TimeUnit.MILLISECONDS) + "毫秒");
}

从日志输出Graceful shutdown aborted with one or more requests still active可以看出，最终直接终止了一个或多个依然活动的请求，【请求执行结束】也没有得到输出。

2023-03-18 10:57:16.020  INFO 22520 --- [nio-8080-exec-1] c.w.controller.安全关闭WEB服务.TestController  : 【请求执行中】
Disconnected from the target VM, address: '127.0.0.1:52322', transport: 'socket'
2023-03-18 10:57:17.471  INFO 22520 --- [extShutdownHook] o.s.b.w.e.tomcat.GracefulShutdown        : Commencing graceful shutdown. Waiting for active requests to complete
2023-03-18 10:57:27.478  INFO 22520 --- [extShutdownHook] o.s.c.support.DefaultLifecycleProcessor  : Failed to shut down 1 bean with phase value 2147483647 within timeout of 10000ms: [webServerGracefulShutdown]
2023-03-18 10:57:27.510  INFO 22520 --- [tomcat-shutdown] o.s.b.w.e.tomcat.GracefulShutdown        : Graceful shutdown aborted with one or more requests still active
2023-03-18 10:57:29.790  INFO 22520 --- [extShutdownHook] o.s.s.concurrent.ThreadPoolTaskExecutor  : Shutting down ExecutorService 'applicationTaskExecutor'
2023-03-18 10:57:29.791  INFO 22520 --- [extShutdownHook] com.alibaba.druid.pool.DruidDataSource   : {dataSource-1} closing ...

如果不配置server.shutdown=graceful，则不会有任何提示以及等待活跃请求执行完成的行为，而是直接关闭服务。

2023-03-18 11:00:15.719  INFO 3376 --- [nio-8080-exec-1] c.w.controller.安全关闭WEB服务.TestController  : 【请求执行中】
Disconnected from the target VM, address: '127.0.0.1:58704', transport: 'socket'
2023-03-18 11:00:21.086  INFO 3376 --- [extShutdownHook] o.s.s.concurrent.ThreadPoolTaskExecutor  : Shutting down ExecutorService 'applicationTaskExecutor'
2023-03-18 11:00:21.086  INFO 3376 --- [extShutdownHook] com.alibaba.druid.pool.DruidDataSource   : {dataSource-1} closing ...
2023-03-18 11:00:21.099  INFO 3376 --- [extShutdownHook] com.alibaba.druid.pool.DruidDataSource   : {dataSource-1} closed

换成Undertow服务也支持

2023-03-18 13:53:53.435  INFO 10804 --- [  XNIO-1 task-1] c.w.controller.安全关闭WEB服务.TestController  : 【请求执行中】
Disconnected from the target VM, address: '127.0.0.1:63225', transport: 'socket'
2023-03-18 13:53:54.546  INFO 10804 --- [extShutdownHook] o.s.b.w.e.undertow.UndertowWebServer     : Commencing graceful shutdown. Waiting for active requests to complete
2023-03-18 13:54:03.451  INFO 10804 --- [  XNIO-1 task-1] c.w.controller.安全关闭WEB服务.TestController  : 【请求执行结束】耗时：10009毫秒
2023-03-18 13:54:03.478  INFO 10804 --- [  XNIO-1 task-1] o.s.b.w.e.undertow.UndertowWebServer     : Graceful shutdown complete
2023-03-18 13:54:03.478  INFO 10804 --- [extShutdownHook] io.undertow                              : stopping server: Undertow - 2.2.3.Final
2023-03-18 13:54:03.487  INFO 10804 --- [extShutdownHook] io.undertow.servlet                      : Destroying Spring FrameworkServlet 'dispatcherServlet'
2023-03-18 13:54:03.489  INFO 10804 --- [extShutdownHook] o.s.s.concurrent.ThreadPoolTaskExecutor  : Shutting down ExecutorService 'applicationTaskExecutor'
2023-03-18 13:54:03.489  INFO 10804 --- [extShutdownHook] com.alibaba.druid.pool.DruidDataSource   : {dataSource-1} closing ...
2023-03-18 13:54:03.506  INFO 10804 --- [extShutdownHook] com.alibaba.druid.pool.DruidDataSource   : {dataSource-1} closed

与Tomcat不同之处，正如官方文档中说明那样，Undertow在关闭期间对于请求会直接返回503，而Tomcat则不会。

Undertow

Tomcat