Microsoft.FeatureManagement Updates

The packages associated with this release are

• Microsoft.FeatureManagement 2.0.0
• Microsoft.FeatureManagement.AspNetCore 2.0.0

Stable Release

This release is the first stable release of the Microsoft.FeatureManagement libraries.

Features

Enumerating Feature Names

The IFeatureManager interface now exposes a way to enumerate all feature names that are registered in the system. This enables work flows where the states of all known features need to be evaluated.

IFeatureManager fm;

await foreach (string featureName in fm.GetFeatureNamesAsync())
{
  await IsEnabledAsync(featureName);
}

Important: Using the await foreach syntax requires using version 8.0 or above of C#.

Missing Feature Filters

When the feature manager tries to evaluate the state of a feature that depends on a missing feature filter it will now throw a FeatureManagementException with the error MissingFeatureFilter.

The new fail-fast behavior can be disabled via feature management options if the old behavior to ignore missing feature filters is desired.

services.Configure<FeatureManagementOptions>(options =>
{
    options.IgnoreMissingFeatureFilters = true;
});

Breaking Changes

• FeatureManager now throws a FeatureManagementException with error AmbiguousFeatureFilter, instead of InvalidOperationException, if a feature makes an ambiguous reference to two or more feature filters.
• Task<bool> ISessionManager.TryGetAsync(string featureName, out bool enabled) has been changed to Task<bool?> ISessionManager.GetAsync(string featureName) to enable async implementations.