Support "Value" metric type for RabbitMQ scaler

[knepe]

Would like to be able to use "Value" metric type for the RabbitMQ scaler, instead of "AverageValue" as it is now.

Use-Case

Want to have min replicas set to 0, so it will have 0 replicas when queue is empty, but as soon as the queue for ex contains 1 to 300 messages it should scale to 1 replica, and between 300-600 it should scale to 2 replicas and so on. There is another issue requesting this feature here: #692

I built a local image to test it out and it works as expected if we use v2beta2.ValueMetricType instead of AverageValueMetricType, but it should be configurable and default to AverageValueMetricType I guess.

Specification

• Make MetricTarget Type configurable

[knepe]

Please discuss this if/how you want to solve this in a more generic way :)
I have a working image I'm using in my cluster here: main...knepe:main (should not be treated as a PR, but more like a POC)

[knepe]

Hey guys, have you had time to discuss this? @zroubalik

[jeffhollan]

Discussed in our standup today - this seems like a good feature worth looking into. Adding to roadmap

[zroubalik]

My only small remark is, how do we handle multiple scalers per ScaledObject? Do we want to allow mixed scenario, I am curious what is the behavior then, whether it won't be confusing for users.

Maybe not 🐱

[knepe]

Hey, any updates on this? :)

[avivgold098]

Hey, this very useful also for the Prometheus Scaler as well

[tomkerkhove]

Can you create a dedicated issue for Promehtues please?

[zroubalik]

I'd prefer some umbrella issue where we can track this effort, because imho it should be done for all scalers.

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed in 7 days if no further activity occurs. Thank you for your contributions.