x-consistent-hash implementation has divide by zero error when no routing key is specified

[RedMu]

No description provided.

[RedMu]

Had to mock up a test case to prove this, ConsistentHashExchange.routingKeyToWeight should throw an IllegalArgumentException rather than trying to return the Hashcode of a non numeric routing key which is not possible on RabbitMQ. When no routing key is specified the weight is returned as 0 which later fails with a divide by zero in selectReceiver.

[ledoyen]

Hi @RedMu, thanks for spotting this.

I agree that no ArithmeticException should be thrown when publishing to a x-consistent-hash bound with a routingKey hashed to 0.

However I wonder what is the behavior of RabbitMq in this situation ?

I will make the test whenever I can find the time to do it.

[RedMu]

Hi Ledoyen,

I made a quick test, when you try to bind without a binding key you get an IOException with the following:

2020-07-03 19:17:18,815 ERROR org.springframework.amqp.rabbit.connection.CachingConnectionFactory [AMQP Connection 127.0.0.1:5672] : Channel shutdown: channel error; protocol method: #method<channel.close>(reply-code=406, reply-text=PRECONDITION_FAILED - The binding key must be an integer: <<>>, class-id=50, method-id=20)

It is not possible to create a binding through the management console without a binding key.

It's actually an IOException that is thrown by the rabbitmq java client code - but it seemed more logical to have an IllegalArgumentException for the mock library.