Spring Boot應用Shutdown的正確姿勢

Spring Boot應用Shutdown的正確姿勢

基于Spring Boot的應用，程序在發(fā)布新版本時，如何正確地停服升級呢？直接 kill -9 pid 肯定是不合適的，可能導致被處理的數(shù)據(jù)處在灰色的中間狀態(tài)。

我們項目分兩類應用，一種是基于Spring Boot的Web項目，涉及Servlet容器，一種是基于Spring Cloud Stream的Consumer應用，來監(jiān)聽消息隊列處理event。下面我針對這兩類應用，添加各自的gracefully shutdown機制。

版本說明

  • Spring Boot 2.0.3.RELEASE
  • Spring Cloud Stream 2.0.0.RELEASE

Web應用

此類應用在停服時，應該先終止Servlet容器響應新的請求，然后待已接收的請求處理完后，再停止服務。項目中使用的是內嵌Tomcat，使用 wilkinsona 的方案來實現(xiàn)。

/**
 * Gracefully shut down tomcat server
 *
 * Ref: https://dzone.com/articles/graceful-shutdown-spring-boot-applications
 */
@Configuration
public class WebConfig {

    @Bean
    public GracefulShutdown gracefulShutdown() {
        return new GracefulShutdown();
    }

    @Bean
    public ConfigurableServletWebServerFactory webServerFactory(GracefulShutdown gracefulShutdown) {
        TomcatServletWebServerFactory factory = new TomcatServletWebServerFactory();
        factory.addConnectorCustomizers(gracefulShutdown);
        return factory;
    }

}


public class GracefulShutdown implements ApplicationListener<ContextClosedEvent>, TomcatConnectorCustomizer {

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

    private volatile Connector connector;

    @Value("${app.shutdownTimeout}")
    int shutdownTimeout;

    @Override
    public void onApplicationEvent(ContextClosedEvent event) {
        this.connector.pause();

        Executor executor = this.connector.getProtocolHandler().getExecutor();

        if (executor instanceof ThreadPoolExecutor) {
            ThreadPoolExecutor threadPoolExecutor = (ThreadPoolExecutor) executor;
            threadPoolExecutor.shutdown();

            try {
                if (threadPoolExecutor.awaitTermination(shutdownTimeout, TimeUnit.SECONDS)) {
                    log.warn("Tomcat thread pool did not shutdown gracefully within " + shutdownTimeout
                            + " seconds. Proceeding with forceful shutdown.");
                }
            } catch (InterruptedException e) {
                Thread.currentThread().interrupt();
            }
        }
    }

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

Consumer應用

項目中使用Spring Cloud Stream來監(jiān)聽RabbitMQ的消息，配置監(jiān)聽比較方便，基本在yml中聲明下，然后再 @EnableBinding @StreamListener 就完了，比如下面專門發(fā)郵件的例子：

spring:
  main:
    web-application-type: none
  cloud:
    stream:
      bindings:
        input:
          consumer:
            maxAttempts: 1
            concurrency: 5
            shutdownTimeout: 40000 # 添加consumer shutdown timeout
          destination: sendMailTopic
          content-type: application/json
          group: mailGroup

@EnableBinding(Sink.class)
public class MailHandler {
    private Logger log = LoggerFactory.getLogger(MailHandler.class);

    @Value("${spring.mail.username}")
    String sendFrom;

    @Value("${spring.profiles.active}")
    String activeProfile;

    @Autowired
    Tracer tracer;

    @Autowired
    JavaMailSender mailSender;

    @Autowired
    LogService logService;

    /**
     * Listen to sendMailTopic of RabbitMQ
     *
     * @param vo MailVO
     */
    @StreamListener(Sink.INPUT)
    public void sendMail(MailVO vo) {
        try {
            String subject = vo.getSubject() + ", Env - " + activeProfile;

            if ("admin".equals(vo.getEmailTo())) {
                this.sendMailToAdmin(vo, subject);
            } else {
                SimpleMailMessage smm = new SimpleMailMessage();
                smm.setFrom(sendFrom);
                smm.setTo(vo.getEmailTo());
                smm.setSubject(subject);
                smm.setText(vo.getContent());
                mailSender.send(smm);
            }
            log.info("Send mail success. mail content - {}", vo);
        } catch (Exception e) {
            log.error("Send mail failed. mail content - {}", vo, e);
        }
    }
}

那針對此類非Web應用如何正確停服呢？

查看 org.springframework.amqp.rabbit.listener.SimpleMessageListenerContainer#doShutdown 可以看到框架已經(jīng)考慮了此類問題，先停止消費消息，然后執(zhí)行 cancellationLock.await 去等待woker線程完成，如果超時就強制停止了。

    @Override
    protected void doShutdown() {
        Thread thread = this.containerStoppingForAbort.get();
        if (thread != null && !thread.equals(Thread.currentThread())) {
            logger.info("Shutdown ignored - container is stopping due to an aborted consumer");
            return;
        }

        try {
            List<BlockingQueueConsumer> canceledConsumers = new ArrayList<>();
            synchronized (this.consumersMonitor) {
                if (this.consumers != null) {
                    Iterator<BlockingQueueConsumer> consumerIterator = this.consumers.iterator();
                    while (consumerIterator.hasNext()) {
                        BlockingQueueConsumer consumer = consumerIterator.next();
                        consumer.basicCancel(true);
                        canceledConsumers.add(consumer);
                        consumerIterator.remove();
                        if (consumer.declaring) {
                            consumer.thread.interrupt();
                        }
                    }
                }
                else {
                    logger.info("Shutdown ignored - container is already stopped");
                    return;
                }
            }
            logger.info("Waiting for workers to finish.");
            boolean finished = this.cancellationLock.await(getShutdownTimeout(), TimeUnit.MILLISECONDS);
            if (finished) {
                logger.info("Successfully waited for workers to finish.");
            }
            else {
                logger.info("Workers not finished.");
                if (isForceCloseChannel()) {
                    canceledConsumers.forEach(consumer -> {
                        if (logger.isWarnEnabled()) {
                            logger.warn("Closing channel for unresponsive consumer: " + consumer);
                        }
                        consumer.stop();
                    });
                }
            }
        }
        catch (InterruptedException e) {
            Thread.currentThread().interrupt();
            logger.warn("Interrupted waiting for workers.  Continuing with shutdown.");
        }

        synchronized (this.consumersMonitor) {
            this.consumers = null;
            this.cancellationLock.deactivate();
        }

    }

但是通過調試代碼發(fā)現(xiàn)，Spring Cloud Stream在創(chuàng)建MessageListenerContainer時并沒有設置shutdownTimeout，所以永遠是默認的5秒，而且在yml的配置中也沒有shutdown超時時間的相關設置。

此時，最簡單直接的辦法就是修改源碼，添加shutdown超時時間的配置以及在創(chuàng)建MessageListenerContainer時使用該配置。修改如下：

org.springframework.cloud.stream.binder.rabbit.RabbitMessageChannelBinder#createConsumerEndpoint

    @Override
    protected MessageProducer createConsumerEndpoint(ConsumerDestination consumerDestination, String group,
            ExtendedConsumerProperties<RabbitConsumerProperties> properties) {
        Assert.state(!HeaderMode.embeddedHeaders.equals(properties.getHeaderMode()),
                "the RabbitMQ binder does not support embedded headers since RabbitMQ supports headers natively");
        String destination = consumerDestination.getName();
        SimpleMessageListenerContainer listenerContainer = new SimpleMessageListenerContainer(
                this.connectionFactory);
        // 這里加上超時時間設置
        listenerContainer.setShutdownTimeout(properties.getShutdownTimeout());
        listenerContainer.setAcknowledgeMode(properties.getExtension().getAcknowledgeMode());
        listenerContainer.setChannelTransacted(properties.getExtension().isTransacted());
        listenerContainer.setDefaultRequeueRejected(properties.getExtension().isRequeueRejected());
        int concurrency = properties.getConcurrency();
        concurrency = concurrency > 0 ? concurrency : 1;
        listenerContainer.setConcurrentConsumers(concurrency);
        int maxConcurrency = properties.getExtension().getMaxConcurrency();
        if (maxConcurrency > concurrency) {
            listenerContainer.setMaxConcurrentConsumers(maxConcurrency);
        }
        listenerContainer.setPrefetchCount(properties.getExtension().getPrefetch());
        listenerContainer.setRecoveryInterval(properties.getExtension().getRecoveryInterval());
        listenerContainer.setTxSize(properties.getExtension().getTxSize());
        listenerContainer.setTaskExecutor(new SimpleAsyncTaskExecutor(consumerDestination.getName() + "-"));
        listenerContainer.setQueueNames(destination);
        listenerContainer.setAfterReceivePostProcessors(this.decompressingPostProcessor);
        listenerContainer.setMessagePropertiesConverter(
                RabbitMessageChannelBinder.inboundMessagePropertiesConverter);
        listenerContainer.setExclusive(properties.getExtension().isExclusive());
        listenerContainer.setMissingQueuesFatal(properties.getExtension().getMissingQueuesFatal());
        if (properties.getExtension().getQueueDeclarationRetries() != null) {
            listenerContainer.setDeclarationRetries(properties.getExtension().getQueueDeclarationRetries());
        }
        if (properties.getExtension().getFailedDeclarationRetryInterval() != null) {
            listenerContainer.setFailedDeclarationRetryInterval(
                    properties.getExtension().getFailedDeclarationRetryInterval());
        }
        if (getApplicationEventPublisher() != null) {
            listenerContainer.setApplicationEventPublisher(getApplicationEventPublisher());
        }
        else if (getApplicationContext() != null) {
            listenerContainer.setApplicationEventPublisher(getApplicationContext());
        }
        listenerContainer.afterPropertiesSet();

        AmqpInboundChannelAdapter adapter = new AmqpInboundChannelAdapter(listenerContainer);
        adapter.setBeanFactory(this.getBeanFactory());
        adapter.setBeanName("inbound." + destination);
        DefaultAmqpHeaderMapper mapper = DefaultAmqpHeaderMapper.inboundMapper();
        mapper.setRequestHeaderNames(properties.getExtension().getHeaderPatterns());
        adapter.setHeaderMapper(mapper);
        ErrorInfrastructure errorInfrastructure = registerErrorInfrastructure(consumerDestination, group, properties);
        if (properties.getMaxAttempts() > 1) {
            adapter.setRetryTemplate(buildRetryTemplate(properties));
            adapter.setRecoveryCallback(errorInfrastructure.getRecoverer());
        }
        else {
            adapter.setErrorMessageStrategy(errorMessageStrategy);
            adapter.setErrorChannel(errorInfrastructure.getErrorChannel());
        }
        return adapter;
    }

package org.springframework.cloud.stream.binder;

@JsonInclude(JsonInclude.Include.NON_DEFAULT)
public class ConsumerProperties {

    /**
     * 添加shutdown超時時間的相關配置
     * Message container shutdown timeout, default is 30s
     */
    private int shutdownTimeout = 30000;

    /**
     * The concurrency setting of the consumer. Default: 1.
     */
    private int concurrency = 1;

    /**
     * Whether the consumer receives data from a partitioned producer. Default: 'false'.
     */
    private boolean partitioned;
    
    // set get ...
}

然后將修改后的spring-cloud-stream-2.0.0.RELEASE和spring-cloud-stream-binder-rabbit-2.0.0.RELEASE發(fā)布到Maven私服，替換官方的版本即可。

最后替換shutdown.sh的腳本，將kill -9 改為kill 或 kill -15

#!/bin/sh

. ./common-env.sh

shutdownService(){
    # Find the service process id
    sid=`ps -ef | grep $1 | grep -v grep | awk '{print $2}'`

    if [ -n "${sid}" ]; then
        echo "Shutdown $1"
        kill ${sid}
    else
        echo "$1 not found"
    fi
}

# Shut down all services
for service in ${oxx_services[*]}
do
   shutdownService ${service}
done

水平有限，能力一般，文中如有錯誤，歡迎大家留言指正。

https://github.com/spring-projects/spring-boot/issues/4657#issuecomment-161354811

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