Being able to get/create composite alarms using tags

[Laxenade]

Feature scope

Alarms

Describe your suggested feature

Currently, in https://github.com/cdklabs/cdk-monitoring-constructs/blob/main/lib/facade/MonitoringFacade.ts#L358-L374, the code calls createdAlarmsWithTag(), which intentionally excludes composite alarms. That behavior makes sense, and I understand there are valid cases where we might not want to include composite alarms.

That said, I think it would be valuable to give users more flexibility and choices. Supporting nested composite alarms (i.e., a composite alarm that references other composite alarms)—is an important use case for advanced alarming. While there are workarounds, none are as clean or intuitive as having native support in the facade.

I also noticed that issues #237 and #618 are requesting similar functionality. So I wanted to ask, is there any blocker that prevents us from, say, introducing an optional flag to include composite alarms in createdAlarmsWithTag()—with the understanding that the user assumes full responsibility for avoiding infinite recursion?

which intentionally excludes composite alarms

I'm not really sure if it was intentional per se, although the behaviour is at least documented.

There's definitely been several instances of people being surprised by that behaviour and requesting otherwise, so I'm not opposed to actually surfacing created composite alarms through the various facade methods, we'd just need to actually keep track of them in some way to allow that to happen.