Support Splunk scaler

[circa10a]

Proposal

I've developed a Splunk scaler to allow folks to autoscale based on data from a saved search. The functionality allows users to autoscale based on integer values return from searches and would work for on-prem or SaaS customers of Splunk.

Scaler Source

Splunk

Scaling Mechanics

Based on data returned from searches in Splunk

Authentication Source

API Token or password from TriggerAuthentication resource

Anything else?

All of the scaler/test code was already written as part of a hackathon internal at Splunk to prove out the functionality. The contribution docs mention opening an issue first for discussion, thus, here I am 😄

[circa10a]

1. Scaler PR: Add Splunk scaler #5905
2. Docs PR: feat: splunk scaler docs keda-docs#1413