How to handle FeatureFlags?

[caiogarcia]

let's say you have a handler to retrieve the weather. And you need to add some business logic on it.

should we spread ifs all over the place to control the flow when the feature flag is on or off? or there is a way to create WeatherHandlerV2 and redirect the flow to the proper handler based on the feature flag?

[caiogarcia]

I figure it out by my self, but if you have the same case you can use the following code.

services.AddMediatR(cfg =>
{
    cfg.TypeEvaluator = (type) =>
    {
        var attribute = type.GetCustomAttribute<FeatureGateAttribute>();
        return attribute == null ||
               attribute.Features.All(feature => configuration.GetValue<bool>(feature));
    };
    cfg.RegisterServicesFromAssemblyContaining(typeof(IServiceCollectionExtensions));
});

And mark your handlers with FeatureGate attribute from Microsoft.FeatureManagement.AspNetCore package.