LogGroup#extractMetric doesn't support '/' character or tokens/derived metric namespace or names.

[sam-goodwin]

LogGroup.extractMetric includes the metric namespace and name in the underlying construct name. This prohibits valid namespaces such as those that contain a /, or any derived token values such as function names etc.

const myFunc = new lambda.Function(..)
logGroup.extractMetric('$.myMetric', `mynamespace${myFunc.functionName}`, 'mymetric');

Throws error:

Error: Construct names cannot include '/': mynamespace/${Token[MyFunction.Ref.13]}_mymetric

[eladb]

Interesting. there's an attempt of extractMetric to use the namespace as a construct name, but if the name includes a token, this whole idea kind of fails.

[rix0rrr]

I expected the namespace to be static while writing this, like MyApp.

[eladb]

Apparently the namespace in @sam-goodwin's case is not static. Even though, we should protect ourselves by checking if unresolved(id) when a construct ID is passed in, no?

[sam-goodwin]

It also doesn't support static namespaces with a / which are valid.

[rix0rrr]

Agreed on both of those.

[eladb]

What I ended up doing is basically allow "/"s to be included in construct IDs, but they are mangled to "--" as soon as the construct is created. I think in most cases that won't be horribly surprising or problematic because it's quite rare for people to actually want to find constructs by their ID. In the rare case, I've added some documentation to that effect.