如何在Langohr中容忍RabbitMQ重启？

Question

我们有Clojure代码,它从Rabbit队列中读取.我们想要容忍RabbitMQ服务器短暂停机的情况,例如在重启(sudo service rabbitmq-server restart)的情况下.

在Langohr 似乎有一些重新连接的规定.我们改编了这个例子clojurewerkz.langohr.examples.recovery.example1(Gist here).与已发布的示例相比,略有差异包括连接参数和lb/publish调用的删除(因为我们使用外部源填充数据).

我们可以成功使用队列中的数据并等待更多消息.但是,当我们重新启动RMQ时(通过sudo托管RabbitMQ的VM 上的上述命令),抛出以下异常:

Caught an exception during connection recovery!
java.io.IOException
    at com.rabbitmq.client.impl.AMQChannel.wrap(AMQChannel.java:106)
    at com.rabbitmq.client.impl.AMQChannel.wrap(AMQChannel.java:102)
    at com.rabbitmq.client.impl.AMQConnection.start(AMQConnection.java:378)
    at com.rabbitmq.client.ConnectionFactory.newConnection(ConnectionFactory.java:516)
    at com.rabbitmq.client.ConnectionFactory.newConnection(ConnectionFactory.java:545)
    at com.novemberain.langohr.Connection.recoverConnection(Connection.java:166)
    at com.novemberain.langohr.Connection.beginAutomaticRecovery(Connection.java:115)
    at com.novemberain.langohr.Connection.access$000(Connection.java:18)
    at com.novemberain.langohr.Connection$1.shutdownCompleted(Connection.java:93)
    at com.rabbitmq.client.impl.ShutdownNotifierComponent.notifyListeners(ShutdownNotifierComponent.java:75)
    at com.rabbitmq.client.impl.AMQConnection$MainLoop.run(AMQConnection.java:573)
Caused by: com.rabbitmq.client.ShutdownSignalException: connection error; reason: java.io.EOFException
    at com.rabbitmq.utility.ValueOrException.getValue(ValueOrException.java:67)
    at com.rabbitmq.utility.BlockingValueOrException.uninterruptibleGetValue(BlockingValueOrException.java:33)
    at com.rabbitmq.client.impl.AMQChannel$BlockingRpcContinuation.getReply(AMQChannel.java:343)
    at com.rabbitmq.client.impl.AMQConnection.start(AMQConnection.java:321)
    ... 8 more
Caused by: java.io.EOFException
    at java.io.DataInputStream.readUnsignedByte(DataInputStream.java:273)
    at com.rabbitmq.client.impl.Frame.readFrom(Frame.java:95)
    at com.rabbitmq.client.impl.SocketFrameHandler.readFrame(SocketFrameHandler.java:131)
    at com.rabbitmq.client.impl.AMQConnection$MainLoop.run(AMQConnection.java:533)

Langohr提供的预期重启机制似乎很可能在它启动时破坏.在这些"硬"重启的情况下,是否存在替代模式？或者,我想我们必须实现连接监视并重试自己.任何建议都是最受欢迎的.

Answer 1

我们曾经看到过这样的堆栈跟踪，但在 Langohr 2.9.0 中我们不再看到它们。重新启动后，我们的 clojure 客户端重新连接，消息再次开始流动。

我们使用默认设置，打开连接和拓扑覆盖，如下所示：

(infof "Automatic recovery enabled? %s" (rmq/automatic-recovery-enabled? connection))
(infof "Topology recovery enabled? %s" (rmq/automatic-topology-recovery-enabled? connection))