Ability to ack messages downstream from source

[01101101]

Messages are acked just after they are pushed downstream.

In my use-case I have to process the message, and if the processing fails, I have to nack the message (message TTL and dead letter exchange are defined on the AMQP queue).

ATM, I have created custom source and sink and ack the message in the sink (for my use case it's ok).

This issue is greatly inspired by this one: ScalaConsultants/reactive-rabbit#13

Is this features useful to anyone? How to implement it?

[drewhk]

We would like to settle on a uniform way to handle acking that works across many stages, but we have not started working on it. Reactive Kafka has support for it already, we would like to extract it to a more generic interop interface possibly.

[01101101]

I think there will be another problem here, from the RabbitMQ doc: "The delivery tag is valid only within the channel from which the message was received. I.e. a client MUST NOT receive a message on one channel and then acknowledge it on another."

But here we open a connection for both the source and the sink.

[drewhk]

But here we open a connection for both the source and the sink.

That is not relevant as the acknowledgement goes to the Source. We have the exact same thing in Reactive Kafka.

[01101101]

I think I miss something, how can the acknowledgement goes to the Source if we ack/nack downstream from the Source?

[drewhk]

you get an envelope with an ack() method. Similar to Camel and other libraries.