在消费者重新连接之前,RabbitMQ会丢失消息

Question

我实现了一个消费者,如果底层连接关闭,它会在一段时间后自动重新连接到代理.我的情况如下:

1. 成功启动RabbitMQ服务器.
2. 成功启动消费者.
3. 发布消息,消费者成功收到消息.

4. 停止RabbitMQ服务器,消费者将显示异常:

   com.rabbitmq.client.ShutdownSignalException:连接错误; 原因:{#method(reply-code = 541,reply-text = INTERNAL_ERROR,class-id = 0,method-id = 0),null,""}.

   然后消费者将在重新连接前睡60秒.

5. 再次启动RabbitMQ服务器.
6. 成功发布消息,命令'list_queues'的结果为0
7. 60秒后,消费者再次连接到RabbitMQ,但现在收到的消息在步骤#6中发布.
8. 发布第三条消息,消费者成功收到了消息.

在这种情况下,重新连接之前发布的所有消息都将丢失.我还做了另一个实验.

1. 启动RabbitMQ,并成功发布消息(未启动任何消费者进程).
2. 停止RabbitMQ,然后重启它.
3. 启动消费者流程,成功接收步骤#1发布的消息.

注意:消费者的QOS是1.我已经研究过RabbitMQ几天了,根据我的理解,消费者应该在重新连接之前发布消息.请帮忙(我根据windows rabbitMQ运行测试).

以下是PUBLISHER:

ConnectionFactory factory = new ConnectionFactory();
factory.setHost(this.getHost());
connection = factory.newConnection();
Channel channel = connection.createChannel();               
channel = conn.createChannel();
// declare a 'topic' type of exchange
channel.exchangeDeclare(exchangeName, "topic");
// Content-type "application/octet-stream", deliveryMode 2
// (persistent), priority zero
channel.basicPublish(exchangeName, routingKey, MessageProperties.PERSISTENT_BASIC, message);
connection.close();

消费者如下:

    @Override
public void consume(final String exchangeName, final String queueName, final String routingKey,
        final int qos) throws IOException, InterruptedException {
    ConnectionFactory factory = new ConnectionFactory();
    factory.setHost(this.getHost());

    while (true) {
        Connection connection = null;
        try {
            connection = factory.newConnection();
            Channel channel = connection.createChannel();

            channel.exchangeDeclare(exchangeName, "topic");
            // declare a durable, non-exclusive, non-autodelete queue.
            channel.queueDeclare(queueName, true, false, false, null);
            channel.queueBind(queueName, exchangeName, routingKey);
            // distribute workload among all consumers, consumer will
            // pre-fetch
            // {qos}
            // messages to local buffer.
            channel.basicQos(qos);

            logger.debug(" [*] Waiting for messages. To exit press CTRL+C");

            QueueingConsumer consumer = new QueueingConsumer(channel);
            // disable auto-ack. If enable auto-ack, RabbitMQ delivers a
            // message to
            // the customer it immediately removes it from memory.
            boolean autoAck = false;
            channel.basicConsume(queueName, autoAck, consumer);

            while (true) {
                QueueingConsumer.Delivery delivery = consumer.nextDelivery();
                try {
                    RabbitMessageConsumer.this.consumeMessage(delivery);
                }
                catch (Exception e) {
                    // the exception shouldn't affect the next message
                    logger.info("[IGNORE]" + e.getMessage());
                }
                channel.basicAck(delivery.getEnvelope().getDeliveryTag(), false);
            }
        }
        catch (Exception e) {
            logger.warn(e);
        }

        if (autoReconnect) {
            this.releaseConn(connection);
            logger.info("[*] Will try to reconnect to remote host(" + this.getHost() + ") in "
                    + this.reconnectInterval / 1000 + " seconds.");
            Thread.sleep(this.getReconnectInterval());
        }
        else
            break;
    }
}

private void releaseConn(Connection conn) {
    try {
        if (conn != null)
            conn.close();
    }
    catch (Exception e) {
        // simply ignore this exception
    }
}

因为它是一个'主题'交换,所以在PUBLISHER上没有声明队列.但是,在第一次测试的第3步,已经声明了持久队列,并且消息也是持久的.我不明白为什么在重新连接之前会丢失消息.

Answer 1

哦,我找到了原因......消息和队列肯定是持久的,但交换不耐用.由于交换不持久,RabbitMQ代理重启之间队列和交换之间的绑定信息将丢失.

现在我声明交换是持久的,消费者可以获得在消费者重启之前和经纪人重启之后发布的消息.

Answer 2

如果在发布时没有队列,则消息将丢失.您是否连接到相同的队列,如果它是持久的,或者您在重新启动RMQ服务器之后发布消息之前重新创建它？听起来像解决方案之一是:

1. 使队列持久并在重新启动后重新连接到该队列
2. 确保在发布之前创建队列.

此外,请确保您重新连接到消费者中的正确队列.1)可能是两种解决方案中较好的一种.