[erlang-questions] RabbitMQ message consumption

[Sölvi Páll Ásgeirsson]

I think you want to use RabbitMQ's message acknowledgement.

The general idea is that you:
- Consume a message
- Process it
- Acknowledge to RabbitMQ that you've processed it, which causes it to be
deleted from the queue.

You can read more at https://www.rabbitmq.com/confirms.html

If you're using the Erlang RabbitMQ client, you can do something like this
when subscribing:

  #'basic.consume_ok'{} = amqp_channel:subscribe(Channel,
#'basic.consume'{queue = Queue, no_ack = false}, self()),

Then, when you've handled your message, you call:

    amqp_channel:cast(Channel, #'basic.ack'{delivery_tag = Tag}).

Hope this helps

Cheers
Sölvi


On Fri, May 12, 2017 at 11:55 AM, Kareem Hepburn <kareemgan@REDACTED>
wrote:

> Is it possible with RabbitMQ to consume a message without it being deleted
> and be deleted manually?
>
> Because let's say I consumed a message and started to process it and half
> way through processing it the application fails. I want to be able to
> re-process that message again. Is it possible to not delete the message and
> delete it manually after my process has successfully completed?
>
> To avoid duplication, I plan to use a secondary database, either Redis or
> Memcache to store the ID of the message to ensure that it's not being
> processed by more than one application.
>
> Thanks!
>
> --
>
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