feat: Add support for basic flags in Feature Management (#350)

Signed-off-by: Mark Johnson <[email protected]>
Co-authored-by: André Silva <[email protected]>

Author: Tazmainiandevil

src/OpenFeature.Contrib.Providers.FeatureManagement/FeatureManagementProvider.cs

@@ -1,6 +1,7 @@
 using Microsoft.Extensions.Configuration;
 using Microsoft.FeatureManagement;
 using Microsoft.FeatureManagement.FeatureFilters;
+using OpenFeature.Constant;
 using OpenFeature.Model;
 using System;
 using System.Collections.Generic;
@@ -50,6 +51,24 @@ public override async Task<ResolutionDetails<bool>> ResolveBooleanValueAsync(str
         {
             var variant = await Evaluate(flagKey, context, CancellationToken.None);
 
+            if (variant == null)
+            {
+                var exists = false;
+                await foreach (var name in featureManager.GetFeatureNamesAsync().WithCancellation(cancellationToken))
+                {
+                    if (!flagKey.Equals(name, StringComparison.OrdinalIgnoreCase)) continue;
+                    exists = true;
+                    break;
+                }
+                var enabled = await featureManager.IsEnabledAsync(flagKey, context, cancellationToken);
+                if (exists)
+                {
+                    return new ResolutionDetails<bool>(flagKey, enabled);
+                }
+
+                return new ResolutionDetails<bool>(flagKey, defaultValue, ErrorType.FlagNotFound, Reason.Error);
+            }
+
             if (Boolean.TryParse(variant?.Configuration?.Value, out var value))
                 return new ResolutionDetails<bool>(flagKey, value);
             return new ResolutionDetails<bool>(flagKey, defaultValue);

test/OpenFeature.Contrib.Providers.FeatureManagement.Test/FeatureManagementProviderSimpleFlagTest.cs

@@ -0,0 +1,28 @@
+using Microsoft.Extensions.Configuration;
+using System.Threading.Tasks;
+using Xunit;
+
+namespace OpenFeature.Contrib.Providers.FeatureManagement.Test
+{
+    public class FeatureManagementProviderSimpleFlagTest
+    {
+        [Theory]
+        [MemberData(nameof(TestData.BooleanSimple), MemberType = typeof(TestData))]
+        public async Task BooleanValue_ShouldReturnExpected(string key, bool defaultValue, bool expectedValue)
+        {
+            // Arrange
+            var configuration = new ConfigurationBuilder()
+                .AddJsonFile("appsettings.enabled.json")
+                .Build();
+
+            var provider = new FeatureManagementProvider(configuration);
+
+            // Act
+            // Invert the expected value to ensure that the value is being read from the configuration
+            var result = await provider.ResolveBooleanValueAsync(key, defaultValue);
+
+            // Assert
+            Assert.Equal(expectedValue, result.Value);
+        }
+    }
+}

test/OpenFeature.Contrib.Providers.FeatureManagement.Test/TestData.cs

@@ -1,9 +1,4 @@
-using System;
-using System.Collections.Generic;
-using System.Dynamic;
-using System.Linq;
-using System.Text;
-using System.Threading.Tasks;
+using System.Collections.Generic;
 
 namespace OpenFeature.Contrib.Providers.FeatureManagement.Test
 {
@@ -14,6 +9,16 @@ internal class TestData
         private static string INVALID_EMAIL = "[email protected]";
         private static string INVALID_GROUP = "missing.group";
 
+        public static IEnumerable<object[]> BooleanSimple()
+        {
+            yield return new object[] { "simple_flag_on", false, true };
+            yield return new object[] { "simple_flag_on", true, true };
+            yield return new object[] { "simple_flag_off", false, false };
+            yield return new object[] { "simple_flag_off", true, false };
+            yield return new object[] { "simple_flag_missing", false, false };
+            yield return new object[] { "simple_flag_missing", true, true };
+        }
+
         public static IEnumerable<object[]> BooleanNoContext()
         {
             yield return new object[] { "MissingFlagKey", true, true };

test/OpenFeature.Contrib.Providers.FeatureManagement.Test/appsettings.enabled.json

@@ -1,4 +1,8 @@
 {
+  "FeatureManagement": {
+    "simple_flag_on": true,
+    "simple_flag_off": false
+  },
   "feature_management": {
     "feature_flags": [
       {