Instrument name validation

Instrument name has to be validated as per the spec. The .NET API itself does not validate this, so the SDK has to validate the instrument name (upon instrument creation), and ignore the instrument (after logging that we are ignoring an instrument due to … reason).

For Views, which provide new name for the Metric, the validation can be done in the AddView itself and can throw/fail fast on AddView.

[cijothomas]

@joaopgrassi Assigned to you! 2 places:

1. Yes instrument publish callback. (this is what gets called when someone does meter.CreateCounter etc)
2. in the AddView, which allows one to rename an instrument. So we should be validating the effective name only, not the original instrument name.

You can start without the View part, and later add it.

[cijothomas]

You are right about the View part - we can only fail fast if the name is know at AddView method itself, and not with the Func returning config option.

I missed to read the part about “duplication” earlier - you are right that even if we do the validation in AddView, the instrument publish still has to do it. Its okay for now - we might be able to optimize this a bit more later (require some more refactoring of provider)