spring SpringApplicationShutdownHook 源码

springboot SpringApplicationShutdownHook 代码

文件路径：/spring-boot-project/spring-boot/src/main/java/org/springframework/boot/SpringApplicationShutdownHook.java

/*
 * Copyright 2012-2022 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      https://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.springframework.boot;

import java.util.Collections;
import java.util.IdentityHashMap;
import java.util.LinkedHashSet;
import java.util.Set;
import java.util.WeakHashMap;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.TimeoutException;
import java.util.concurrent.atomic.AtomicBoolean;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationListener;
import org.springframework.context.ConfigurableApplicationContext;
import org.springframework.context.event.ContextClosedEvent;
import org.springframework.util.Assert;

/**
 * A {@link Runnable} to be used as a {@link Runtime#addShutdownHook(Thread) shutdown
 * hook} to perform graceful shutdown of Spring Boot applications. This hook tracks
 * registered application contexts as well as any actions registered via
 * {@link SpringApplication#getShutdownHandlers()}.
 *
 * @author Andy Wilkinson
 * @author Phillip Webb
 * @author Brian Clozel
 */
class SpringApplicationShutdownHook implements Runnable {

	private static final int SLEEP = 50;

	private static final long TIMEOUT = TimeUnit.MINUTES.toMillis(10);

	private static final Log logger = LogFactory.getLog(SpringApplicationShutdownHook.class);

	private final Handlers handlers = new Handlers();

	private final Set<ConfigurableApplicationContext> contexts = new LinkedHashSet<>();

	private final Set<ConfigurableApplicationContext> closedContexts = Collections.newSetFromMap(new WeakHashMap<>());

	private final ApplicationContextClosedListener contextCloseListener = new ApplicationContextClosedListener();

	private final AtomicBoolean shutdownHookAdded = new AtomicBoolean();

	private boolean inProgress;

	SpringApplicationShutdownHandlers getHandlers() {
		return this.handlers;
	}

	void registerApplicationContext(ConfigurableApplicationContext context) {
		addRuntimeShutdownHookIfNecessary();
		synchronized (SpringApplicationShutdownHook.class) {
			assertNotInProgress();
			context.addApplicationListener(this.contextCloseListener);
			this.contexts.add(context);
		}
	}

	private void addRuntimeShutdownHookIfNecessary() {
		if (this.shutdownHookAdded.compareAndSet(false, true)) {
			addRuntimeShutdownHook();
		}
	}

	void addRuntimeShutdownHook() {
		Runtime.getRuntime().addShutdownHook(new Thread(this, "SpringApplicationShutdownHook"));
	}

	void deregisterFailedApplicationContext(ConfigurableApplicationContext applicationContext) {
		synchronized (SpringApplicationShutdownHook.class) {
			Assert.state(!applicationContext.isActive(), "Cannot unregister active application context");
			SpringApplicationShutdownHook.this.contexts.remove(applicationContext);
		}
	}

	@Override
	public void run() {
		Set<ConfigurableApplicationContext> contexts;
		Set<ConfigurableApplicationContext> closedContexts;
		Set<Runnable> actions;
		synchronized (SpringApplicationShutdownHook.class) {
			this.inProgress = true;
			contexts = new LinkedHashSet<>(this.contexts);
			closedContexts = new LinkedHashSet<>(this.closedContexts);
			actions = new LinkedHashSet<>(this.handlers.getActions());
		}
		contexts.forEach(this::closeAndWait);
		closedContexts.forEach(this::closeAndWait);
		actions.forEach(Runnable::run);
	}

	boolean isApplicationContextRegistered(ConfigurableApplicationContext context) {
		synchronized (SpringApplicationShutdownHook.class) {
			return this.contexts.contains(context);
		}
	}

	void reset() {
		synchronized (SpringApplicationShutdownHook.class) {
			this.contexts.clear();
			this.closedContexts.clear();
			this.handlers.getActions().clear();
			this.inProgress = false;
		}
	}

	/**
	 * Call {@link ConfigurableApplicationContext#close()} and wait until the context
	 * becomes inactive. We can't assume that just because the close method returns that
	 * the context is actually inactive. It could be that another thread is still in the
	 * process of disposing beans.
	 * @param context the context to clean
	 */
	private void closeAndWait(ConfigurableApplicationContext context) {
		if (!context.isActive()) {
			return;
		}
		context.close();
		try {
			int waited = 0;
			while (context.isActive()) {
				if (waited > TIMEOUT) {
					throw new TimeoutException();
				}
				Thread.sleep(SLEEP);
				waited += SLEEP;
			}
		}
		catch (InterruptedException ex) {
			Thread.currentThread().interrupt();
			logger.warn("Interrupted waiting for application context " + context + " to become inactive");
		}
		catch (TimeoutException ex) {
			logger.warn("Timed out waiting for application context " + context + " to become inactive", ex);
		}
	}

	private void assertNotInProgress() {
		Assert.state(!SpringApplicationShutdownHook.this.inProgress, "Shutdown in progress");
	}

	/**
	 * The handler actions for this shutdown hook.
	 */
	private class Handlers implements SpringApplicationShutdownHandlers {

		private final Set<Runnable> actions = Collections.newSetFromMap(new IdentityHashMap<>());

		@Override
		public void add(Runnable action) {
			Assert.notNull(action, "Action must not be null");
			synchronized (SpringApplicationShutdownHook.class) {
				assertNotInProgress();
				this.actions.add(action);
			}
		}

		@Override
		public void remove(Runnable action) {
			Assert.notNull(action, "Action must not be null");
			synchronized (SpringApplicationShutdownHook.class) {
				assertNotInProgress();
				this.actions.remove(action);
			}
		}

		Set<Runnable> getActions() {
			return this.actions;
		}

	}

	/**
	 * {@link ApplicationListener} to track closed contexts.
	 */
	private class ApplicationContextClosedListener implements ApplicationListener<ContextClosedEvent> {

		@Override
		public void onApplicationEvent(ContextClosedEvent event) {
			// The ContextClosedEvent is fired at the start of a call to {@code close()}
			// and if that happens in a different thread then the context may still be
			// active. Rather than just removing the context, we add it to a {@code
			// closedContexts} set. This is weak set so that the context can be GC'd once
			// the {@code close()} method returns.
			synchronized (SpringApplicationShutdownHook.class) {
				ApplicationContext applicationContext = event.getApplicationContext();
				SpringApplicationShutdownHook.this.contexts.remove(applicationContext);
				SpringApplicationShutdownHook.this.closedContexts
						.add((ConfigurableApplicationContext) applicationContext);
			}
		}

	}

}

相关信息

spring 源码目录

相关文章

spring AotProcessor 源码

spring ApplicationArguments 源码

spring ApplicationContextFactory 源码

spring ApplicationEnvironment 源码

spring ApplicationReactiveWebEnvironment 源码

spring ApplicationRunner 源码

spring ApplicationServletEnvironment 源码

spring Banner 源码

spring BeanDefinitionLoader 源码

spring BootstrapContext 源码