重新部署 Tomcat 后 Kafka 流错误

Question

我在我的项目中使用 kafka 流。我将我的项目编译为 war 并在 tomcat 中运行它。

我的项目按我的意愿运行，没有任何错误。如果我先停止 tomcat 然后启动它，它可以正常工作。 但是，如果我在不停止 tomcat 的情况下重新部署（取消部署和部署）服务，我就会开始出错。在我做研究的时候，有资料说tomcat缓存了老版本的服务。即使我应用了一些解决方案，我也无法找到解决方案。如果您能帮助我，我将不胜感激。

我想再说一遍。我的代码块工作正常。如果我第一次在 tomcat 中运行该服务，我不会收到错误消息。或者，如果我完全关闭 tomcat 并重新启动它，我不会收到错误消息。但是，如果我在不停止 tomcat 的情况下重新部署（取消部署和部署）服务，就会开始出现错误。

我在下面分享一个小代码块。

Properties streamConfiguration = kafkaStreamsConfiguration.createStreamConfiguration(createKTableGroupId(), new AppSerdes.DataWrapperSerde());
StreamsBuilder streamsBuilder = new StreamsBuilder();
KTable<String, DataWrapper> kTableDataWrapper = streamsBuilder.table(topicAction.getTopicName());
KTable<String, DataWrapper> kTableWithStore = kTableDataWrapper.filter((key, dataWrapper) -> key != null && dataWrapper != null, Materialized.as(createStoreName()));

kTableWithStore.toStream().filter((key, dataWrapper) -> // Filter)
        .mapValues((ValueMapperWithKey<String, DataWrapper, Object>) (key, dataWrapper) -> {
            // Logics
        })
        .to(createOutputTopicName());

this.kafkaStreams = new KafkaStreams(streamsBuilder.build(), streamConfiguration);
this.kafkaStreams.start();
Runtime.getRuntime().addShutdownHook(new Thread(() -> {
    if (kafkaStreams != null) {
        kafkaStreams.close();
    }
}));


public Properties createStreamConfiguration(String appId, Serde serde) {
    Properties properties = new Properties();
    properties.put(StreamsConfig.APPLICATION_ID_CONFIG, appId);
    properties.put(StreamsConfig.BOOTSTRAP_SERVERS_CONFIG, kafkaBrokers);
    properties.put(StreamsConfig.DEFAULT_KEY_SERDE_CLASS_CONFIG, Serdes.String().getClass());
    properties.put(StreamsConfig.DEFAULT_VALUE_SERDE_CLASS_CONFIG, serde.getClass());
    properties.put(StreamsConfig.COMMIT_INTERVAL_MS_CONFIG, dynamicKafkaSourceTopologyConfiguration.getkTableCommitIntervalMs());
    properties.put(StreamsConfig.CACHE_MAX_BYTES_BUFFERING_CONFIG, dynamicKafkaSourceTopologyConfiguration.getkTableMaxByteBufferMB() * 1024 * 1024);
    properties.put(StreamsConfig.STATE_DIR_CONFIG, KafkaStreamsConfigurationConstants.stateStoreLocation);
    return properties;

}

错误：

2022-02-16 14:19:39.663  WARN 9529 --- [     Thread-462] o.a.k.s.p.i.StateDirectory               : Using /tmp directory in the state.dir property can cause failures with writing the checkpoint file due to the fact that this directory can be cleared by the OS
2022-02-16 14:19:39.677 ERROR 9529 --- [     Thread-462] o.a.k.s.p.i.StateDirectory               : Unable to obtain lock as state directory is already locked by another process
2022-02-16 14:19:39.702 ERROR 9529 --- [     Thread-462] f.t.s.c.- Message : Unable to initialize state, this can happen if multiple instances of Kafka Streams are running in the same state directory - Localized Message : Unable to initialize state, this can happen if multiple instances of Kafka Streams are running in the same state directory - Print Stack Trace : org.apache.kafka.streams.errors.StreamsException: Unable to initialize state, this can happen if multiple instances of Kafka Streams are running in the same state directory
        at org.apache.kafka.streams.processor.internals.StateDirectory.initializeProcessId(StateDirectory.java:186)
        at org.apache.kafka.streams.KafkaStreams.<init>(KafkaStreams.java:681)
        at org.apache.kafka.streams.KafkaStreams.<init>(KafkaStreams.java:657)
        at org.apache.kafka.streams.KafkaStreams.<init>(KafkaStreams.java:567)

Answer 1

我认为这是因为

Runtime.getRuntime().addShutdownHook(new Thread(() -> {
    if (kafkaStreams != null) {
        kafkaStreams.close();
    }
}));

在重新部署期间没有被调用，因为 JVM 进程继续运行。请尝试其他方式在重新部署您的应用程序时收到通知，例如使用ServletContextListener

Answer 2

感谢@udalmik，我的问题得到了解决。

我通过从 DisposableBean 扩展我的 bean 解决了我的问题。

此外，我还有原型 bean。该解决方案不适用于我的原型 bean。 我正在为原型和单例 bean 编写我的解决方案。

// For Singleton Bean
@Service
public class PersonSingletonBean implements DisposableBean {
    @Override
    public void destroy() throws Exception {
        if (kafkaStreams != null) {
            kafkaStreams.close();
        }
    }
}

---

// For PrototypeBean
@Service
@Scope(ConfigurableBeanFactory.SCOPE_PROTOTYPE)
public class PersonPrototypeBean implements DisposableBean {

    @Override
    public void destroy() {
        if (kafkaStreams != null) {
            kafkaStreams.close();
        }
    }

}

@Service
public class PersonPrototypeBeanList implements DisposableBean {

    private final List<PersonPrototypeBean> personPrototypeBeanList = Collections.synchronizedList(new ArrayList<>());

    public void addToPersonPrototypeBeanList(PersonPrototypeBean personPrototypeBean) {
        personPrototypeBeanList.add(personPrototypeBean);
    }

    public void destroy() throws Exception {
        synchronized (personPrototypeBeanList) {
            for (PersonPrototypeBean personPrototypeBean : personPrototypeBeanList) {
                if (personPrototypeBean != null) {
                    ((DisposableBean) personPrototypeBean).destroy();
                }
            }
            personPrototypeBeanList.clear();
        }
    }
}