AODH Keda scaler

[Rodolfodc]

Create AODH Keda Scaler following the Keda API for scalers, integrating existing code for openstack and providing improvements when possible

Use-Case

Development of the Keda scaler completly working

Specification

• Scaler must be ing accordance with Keda structures and patterns
• Scaler must perform the following filtering
  • Default metric is activated alarms quantity, there must be a defualt quantity
  • If user chooses to filter alarms by name, the scaler should filter retrieved alarms by name
  • If user chooses to filter alarms by severity, the scaler should filter the alarms by it's severity (User may be able to input as many severities as he wants?.
  • If user choose to combine filterings, the scaler should be able to perform this filtering before metrics be analyzed.
    • Check if there's a way to make this filter on request instead of on scaler
    • All filtering must be done before metrics check.
• Definition of Done: Scaler code ready and it's running and properly working whithin Keda.

[Rodolfodc]

Improvements suggestions: The AODH API have a capabilities endpoint, where it returns what kind of queries are able in the AODH API. It would be itneresting to create a strategy pattern that uses complex API queries when its activated to perform the filterings, and, when not activated, use another strategy that make the filtering on the Keda code