Spring Boot 优雅关闭

Question

我正在开发一个由嵌入式 Tomcat 支持的 Spring Boot 应用程序，我需要通过以下步骤开发一个优雅的关闭：

1. 停止处理新的 HTTP 请求（停止 Web 容器）
2. 处理所有已接受的请求
3. 关闭 Spring ApplicationContext

*按顺序执行上述步骤（一个接一个）

我怎样才能做到这一点？

附： Spring Boot 1.5.20.RELEASE，Java 8

Answer 1

它很简单，Spring boot 本身就提供了功能。 https://docs.spring.io/spring-boot/docs/current/reference/htmlsingle/#boot-features-application-exit

void shoutdown(){
       System.out.println("====+= Shoutdown +++===");
       System.exit(SpringApplication.exit(apc, this.exitCodeGenerator()));
      
   }

您可以在输出中看到所有当前线程都已关闭。 输出：

====+= 大喊+++===

2020-06-09 11:21:45,543
DEBUG[main][c.u.j.c.EnableEncryptablePropertiesBeanFactoryPostProcessor]
Application Event Raised: ExitCodeEvent  2020-06-09 11:21:45,543
DEBUG[main][c.u.j.c.EnableEncryptablePropertiesBeanFactoryPostProcessor]
Application Event Raised: ExitCodeEvent  2020-06-09 11:21:45,546
DEBUG[main][c.u.j.c.EnableEncryptablePropertiesBeanFactoryPostProcessor]
Application Event Raised: ContextClosedEvent  2020-06-09 11:21:45,546
DEBUG[main][c.u.j.c.EnableEncryptablePropertiesBeanFactoryPostProcessor]
Application Event Raised: ContextClosedEvent  2020-06-09 11:21:45,547
INFO [main][o.a.kafka.clients.producer.KafkaProducer] [Producer
clientId=producer-1] Closing the Kafka producer with timeoutMillis =
30000 ms.  2020-06-09 11:21:45,548
DEBUG[kafka-producer-network-thread |
producer-1][o.a.k.clients.producer.internals.Sender] [Producer
clientId=producer-1] Beginning shutdown of Kafka producer I/O thread,
sending remaining records.  2020-06-09 11:21:45,551
DEBUG[kafka-producer-network-thread |
producer-1][org.apache.kafka.common.metrics.Metrics] Removed sensor
with name connections-closed:  2020-06-09 11:21:45,554
DEBUG[kafka-producer-network-thread |
producer-1][org.apache.kafka.common.metrics.Metrics] Removed sensor
with name connections-created:  2020-06-09 11:21:45,554
DEBUG[kafka-producer-network-thread |
producer-1][org.apache.kafka.common.metrics.Metrics] Removed sensor
with name successful-authentication:  2020-06-09 11:21:45,558
DEBUG[kafka-producer-network-thread |
producer-1][org.apache.kafka.common.metrics.Metrics] Removed sensor
with name failed-authentication:  2020-06-09 11:21:45,558
DEBUG[kafka-producer-network-thread |
producer-1][org.apache.kafka.common.metrics.Metrics] Removed sensor
with name bytes-sent-received:  2020-06-09 11:21:45,559
DEBUG[kafka-producer-network-thread |
producer-1][org.apache.kafka.common.metrics.Metrics] Removed sensor
with name bytes-sent:  2020-06-09 11:21:45,559
DEBUG[kafka-producer-network-thread |
producer-1][org.apache.kafka.common.metrics.Metrics] Removed sensor
with name bytes-received:  2020-06-09 11:21:45,560
DEBUG[kafka-producer-network-thread |
producer-1][org.apache.kafka.common.metrics.Metrics] Removed sensor
with name select-time:  2020-06-09 11:21:45,561
DEBUG[kafka-producer-network-thread |
producer-1][org.apache.kafka.common.metrics.Metrics] Removed sensor
with name io-time:  2020-06-09 11:21:45,570
DEBUG[kafka-producer-network-thread |
producer-1][org.apache.kafka.common.metrics.Metrics] Removed sensor
with name node--1.bytes-sent  2020-06-09 11:21:45,570
DEBUG[kafka-producer-network-thread |
producer-1][org.apache.kafka.common.metrics.Metrics] Removed sensor
with name node--1.bytes-received  2020-06-09 11:21:45,570
DEBUG[kafka-producer-network-thread |
producer-1][org.apache.kafka.common.metrics.Metrics] Removed sensor
with name node--1.latency  2020-06-09 11:21:45,571
DEBUG[kafka-producer-network-thread |
producer-1][org.apache.kafka.common.metrics.Metrics] Removed sensor
with name node-0.bytes-sent  2020-06-09 11:21:45,571
DEBUG[kafka-producer-network-thread |
producer-1][org.apache.kafka.common.metrics.Metrics] Removed sensor
with name node-0.bytes-received  2020-06-09 11:21:45,573
DEBUG[kafka-producer-network-thread |
producer-1][org.apache.kafka.common.metrics.Metrics] Removed sensor
with name node-0.latency  2020-06-09 11:21:45,573
DEBUG[kafka-producer-network-thread |
producer-1][o.a.k.clients.producer.internals.Sender] [Producer
clientId=producer-1] Shutdown of Kafka producer I/O thread has
completed.  2020-06-09 11:21:45,607
DEBUG[main][o.a.kafka.clients.producer.KafkaProducer] [Producer
clientId=producer-1] Kafka producer has been closed  2020-06-09
11:21:45,611 DEBUG[main][o.hibernate.internal.SessionFactoryImpl]
HHH000031: Closing  2020-06-09 11:21:45,611
DEBUG[main][o.h.type.spi.TypeConfiguration$Scope] Un-scoping
TypeConfiguration
[org.hibernate.type.spi.TypeConfiguration$Scope@5dfd31f4] from
SessionFactory [org.hibernate.internal.SessionFactoryImpl@62a54948] 
2020-06-09 11:21:45,612
DEBUG[main][o.h.s.i.AbstractServiceRegistryImpl] Implicitly
destroying ServiceRegistry on de-registration of all child
ServiceRegistries  2020-06-09 11:21:45,613
DEBUG[main][o.h.b.r.i.BootstrapServiceRegistryImpl] Implicitly
destroying Boot-strap registry on de-registration of all child
ServiceRegistries  2020-06-09 11:21:45,613 INFO
[main][com.zaxxer.hikari.HikariDataSource] HikariPool-1 - Shutdown
initiated...  2020-06-09 11:21:45,754 INFO
[main][com.zaxxer.hikari.HikariDataSource] HikariPool-1 - Shutdown
completed.

Answer 2

Spring Boot 2.3（2020 年 5 月发布）中添加了正常关闭支持。这允许在关闭上下文和关闭容器之前完成活动请求。

启用优雅关机后，应用程序将在关机时依次执行以下步骤：

• 停止接受新请求
• 将等待一些可配置时间来处理已接受的请求
• 停止容器
• 停止嵌入式服务器

来自release notes：

所有四个嵌入式 Web 服务器（Jetty、Reactor Netty、Tomcat 和 Undertow）以及反应式和基于 Servlet 的 Web 应用程序都支持优雅关闭。当使用server.shutdown=graceful 启用时，在关闭时，Web 服务器将不再允许新请求，并将等待活动请求完成的宽限期。可以使用spring.lifecycle.timeout-per-shutdown-phase 配置宽限期。

---

• 要启用正常关机，请将server.shutdown=graceful 添加到属性中（默认设置为immediate）。
• 可以使用spring.lifecycle.timeout-per-shutdown-phase 属性配置宽限期（例如：spring.lifecycle.timeout-per-shutdown-phase=1m。

---

对于 Spring Boot this Spring GitHub issue 中所述。

Answer 3

我最终得到了：

import java.util.concurrent.Executor;
import java.util.concurrent.ThreadPoolExecutor;
import java.util.concurrent.TimeUnit;
import org.apache.catalina.connector.Connector;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.boot.context.embedded.tomcat.TomcatConnectorCustomizer;
import org.springframework.context.ApplicationListener;
import org.springframework.context.event.ContextClosedEvent;

public class GracefulShutdown implements TomcatConnectorCustomizer, ApplicationListener<ContextClosedEvent> {

  private static final Logger log = LoggerFactory.getLogger(GracefulShutdown.class);
  private volatile Connector connector;

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

  @Override
  public void onApplicationEvent(ContextClosedEvent contextClosedEvent) {
    log.info("Protocol handler is shutting down");

    this.connector.pause();
    Executor executor = this.connector.getProtocolHandler().getExecutor();
    if (executor instanceof ThreadPoolExecutor) {
      try {
        ThreadPoolExecutor threadPoolExecutor = (ThreadPoolExecutor) executor;
        threadPoolExecutor.shutdown();

        if (!threadPoolExecutor.awaitTermination(30, TimeUnit.SECONDS))
          log.warn("Tomcat thread pool did not shut down gracefully within 30 seconds. Proceeding with forceful shutdown");
        else
          log.info("Protocol handler shut down");

      } catch (InterruptedException e) {
        Thread.currentThread().interrupt();
      }
    }
  }
}

还有一些额外的 bean：

import org.springframework.boot.context.embedded.EmbeddedServletContainerFactory;
import org.springframework.boot.context.embedded.tomcat.TomcatEmbeddedServletContainerFactory;
...
  @Bean
  public GracefulShutdown gracefulShutdown() {
    return new GracefulShutdown();
  }

  @Bean
  public EmbeddedServletContainerFactory servletContainer(final GracefulShutdown gracefulShutdown) {
    TomcatEmbeddedServletContainerFactory factory = new TomcatEmbeddedServletContainerFactory();
    factory.addConnectorCustomizers(gracefulShutdown);
    return factory;
  }
...