Add support to specify custom http timeout only for RabbitMQ Scaler

[JorTurFer]

Proposal

My proposal is to add the support to specify a specific timeout to use for each trigger when you are using RabbitMQ Scaler.
It could be something like this:

triggers:
- type: rabbitmq
  metadata:
    host: amqp://localhost:5672/vhost # Optional. If not specified, it must be done by using TriggerAuthentication.
    ...
    httpTimeout: 10000 

In cases where it's not defined, KEDA_HTTP_DEFAULT_TIMEOUT should be used

Use-Case

When you are using http protocol with regex, it could need more time than KEDA_HTTP_DEFAULT_TIMEOUT to get the response. It's possible to customize the timeout but only as a global customization. This could be enough in some cases but if you are using KEDA in several not related workloads, this could be a problem.

In our use case, our production RabbitMQ cluster has more than 1k queues, and it needs 5-10 in some cases to response with the queues which match the regex. If we want to use other scale, we would like to avoid having 15-30sec (arbitrary value) in other scalers which uses HTTP protocol

Anything else?

I can do it :)

[tomkerkhove]

Is there any reason why the http prefix would be required? Other protocols don''t support this?

[JorTurFer]

I don't know if AMQ client supports it, if it supports, the key can be timeout directly instead httpTimeout
I will take a look during the task if you agree :)

[JorTurFer]

I have taken a look at this and in theory it's possible to set the timeout in amqp connection, but probably it's unnecessary because the default timeout using amqp is 30 seconds instead KEDA_HTTP_DEFAULT_TIMEOUT (3s as default).
It could be totally enough for amqp purposes.
I'm not sure if this option is useful in amqp scenarios 😪
WDYT?

[tomkerkhove]

It's ok to keep as-is then for me, thanks for checking.