Loglevel of undefined features too high

[Tornhoof]

In #140 a functionality was added to throw if features are not defined, additionally a log message with Level Warning was added if the throw flag is not enabled.
This now means, that everyone who has undefined feature flags and uses the method IsEnabledAsync gets a warning log entry.
Is that the expected behaviour?
In one of the products I maintain, I do not define non-relevant Features as false (most features are true/false), but now I received questions from customers why completely unknown features show up as warnings, features they do not know about. I specifically do not define the non-relevant Features as false, as the customers do not need to know them and the list is rather long.

I'm perfectly aware that I can configure the log level to remove the warnings, but the log level is also under customer's control. So what is my solution at the moment?
Instead of just calling IsEnabledAsync(), I call GetFeatureNamesAsync first and do a contains in there too. Which is, from my pov, strange.
Is there a good reason this message has to be warning, maybe @zhenlan can chime in, he suggested the change for it.

You might want to change the example on the main page to include that behavior, in the code snippet for IsEnabledAsync

[jimmyca15]

Is that the expected behaviour?

Yes. This provides a notification mechanism for when features are excluded/misspelt but doesn't cause an application crash. More details on the motivation are in this issue: Azure/AppConfiguration#382

You mentioned the possibility of excluding the log category, but that the customer has control over that. Is that the case even if you do it programmatically such as in this example: https://docs.microsoft.com/en-us/aspnet/core/fundamentals/logging/?view=aspnetcore-5.0#apply-log-filter-rules-in-code-1

[Tornhoof]

Thank you for that link with the explanation.
I'll probably simply replace the library with my own code, as my requirements are extremely basic.

As this is by design, I'll close this.