java - 防止 ActiveMQ 重新连接失败时自动退出

Question

我设置了一个小型 spring-boot 应用程序，它连接到 ActiveMQ 上的一个或多个主题，这些主题在启动时在应用程序的 application.properties 文件中设置 - 然后将这些消息发送到数据库。

一切正常，但我在尝试实现故障转移时遇到了一些问题 - 基本上，应用程序将尝试重新连接，但在一定次数的重试后，应用程序进程将自动退出，阻止重试(理想情况下，我希望应用程序永远重试，直到手动终止或 ActiveMQ 再次可用)。我已经尝试将连接 URL 中的连接选项(例如 maxReconnectAttempts)(在 application.properties 中使用 url.options)显式设置为 -1/0/99999 但没有这些似乎是正确的，因为每次的行为都是一样的。通过查看关于 Apache's own reference page 的建议我也希望这种行为也能作为默认行为。

如果有人有任何建议强制应用程序不退出，我将不胜感激!我认为重要的代码部分如下:

@Configuration
public class AmqConfig {

    private static final Logger LOG = LogManager.getLogger(AmqConfig.class);
    private static final String LOG_PREFIX = "[AmqConfig] ";

    private String clientId;

    private static ArrayList<String> amqUrls = new ArrayList<>();
    private static String amqConnectionUrl;
    private static Integer numSubs;
    private static ArrayList<String> destinations = new ArrayList<>();

    @Autowired
    DatabaseService databaseService;

    public AmqConfig (@Value("${amq.urls}") String[] amqUrl,
                      @Value("${amq.options}") String amqOptions,
                      @Value("${tocCodes}") String[] tocCodes,
                      @Value("${amq.numSubscribers}") Integer numSubs,
                      @Value("${clientId}") String clientId) throws UnknownHostException {

        Arrays.asList(amqUrl).forEach(url -> {
            amqUrls.add("tcp://" + url);
        });

        String amqServerAddress = "failover:(" + String.join(",", amqUrls) + ")";
        String options = Strings.isNullOrEmpty(amqOptions) ? "" : "?" + amqOptions;

        this.amqConnectionUrl = amqServerAddress + options;

        this.numSubs = Optional.ofNullable(numSubs).orElse(4);
        this.clientId = Strings.isNullOrEmpty(clientId) ? InetAddress.getLocalHost().getHostName() : clientId;

        String topic = "Consumer." + this.clientId + ".VirtualTopic.Feed";

        if (tocCodes.length > 0){
            Arrays.asList(tocCodes).forEach(s -> destinations.add(topic + "_" + s));
        } else { // no TOC codes = connecting to default feed
            destinations.add(topic);
        }
    }

    @Bean
    public ActiveMQConnectionFactory connectionFactory() throws JMSException {

        LOG.info("{}Connecting to AMQ at {}", LOG_PREFIX, amqConnectionUrl);
        LOG.info("{}Using client id {}", LOG_PREFIX, clientId);
        ActiveMQConnectionFactory connectionFactory =
                new ActiveMQConnectionFactory(amqConnectionUrl);

        Connection conn = connectionFactory.createConnection();
        conn.setClientID(clientId);
        conn.setExceptionListener(new AmqExceptionListener());
        conn.start();

        destinations.forEach(destinationName -> {
            try {
                for (int i = 0; i < numSubs; i++) {
                    Session session = conn.createSession(false, Session.AUTO_ACKNOWLEDGE);
                    Destination destination = session.createQueue(destinationName);
                    MessageConsumer messageConsumer = session.createConsumer(destination);
                    messageConsumer.setMessageListener(new MessageReceiver(databaseService, destinationName));
                }

            } catch (JMSException e) {
                LOG.error("{}Error setting up queue @ {}", LOG_PREFIX, destinationName);
                LOG.error(e.getMessage());
            }
        });

        return connectionFactory;
    }
}


public class MessageReceiver implements MessageListener, ExceptionListener {

     public static final Logger LOG = LogManager.getLogger(MessageReceiver.class);
     private static final String LOG_PREFIX = "[Message Receiver] ";

     private DatabaseService databaseService;

     public MessageReceiver(DatabaseService databaseService, String destinationName){
         this.databaseService = databaseService;
         LOG.info("{}Creating MessageReceiver for queue with destination: {}", LOG_PREFIX, destinationName);
     }

     @Override
     public void onMessage(Message message) {

         String messageText = null;

         if (message instanceof TextMessage) {
             TextMessage tm = (TextMessage) message;
             try {
                 messageText = tm.getText();
             } catch (JMSException e) {
                 LOG.error("{} Error getting message from AMQ", e);
             }
         } else if (message instanceof ActiveMQMessage) {
             messageText = message.toString();
         } else {
             LOG.warn("{}Unrecognised message type, cannot process", LOG_PREFIX);
             LOG.warn(message.toString());
         }

         try {
             databaseService.sendMessageNoResponse(messageText);
         } catch (Exception e) {
             LOG.error("{}Unable to acknowledge message from AMQ. Message: {}", LOG_PREFIX, messageText, e);
         }
     }
}

 public class AmqExceptionListener implements ExceptionListener {

     public static final Logger LOG = LogManager.getLogger(AmqExceptionListener.class);
     private static final String LOG_PREFIX = "[AmqExceptionListener ] ";

     @Override
     public void onException(JMSException e){
         LOG.error("{}Exception thrown by ActiveMQ", LOG_PREFIX, e);
     }
 }

我从我的应用程序中获得的控制台输出如下所示(抱歉，因为它没有太大意义)

[2019-12-12 14:43:30.292] [WARN ] Transport (tcp://[address]:61616) failed , attempting to automatically reconnect: java.io.EOFException
[2019-12-12 14:43:51.098] [WARN ] Failed to connect to [tcp://[address]:61616] after: 10 attempt(s) continuing to retry.

Process finished with exit code 0

Answer 1

非常有趣的问题!

配置 maxReconnectAttempts=-1 会导致连接尝试永远重试，但我觉得这里的问题如下:

1. 您在 App 创建 Bean 时尝试连接到 ActiveMQ startup，如果APP启动时ActiveMQ没有运行，则 Bean 创建将永远重试连接尝试，从而导致 超时，不让APP启动。
2. 此外，当 ActiveMQ 中途停止运行时，您不会重新尝试连接，因为它是在@Bean 内部完成的，只会在应用程序启动时发生

因此连接不应该在创建 Bean 时发生，但也许可以在应用程序启动后完成(可能在 @PostConstruct block 内)

这些只是提示，你需要把它向前推进

希望这对您有所帮助!

祝你好运!