[Feature Flags] Add flag evaluation metrics via OpenFeature hook

tracer/build/PackageVersionsGeneratorDefinitions.json

@@ -968,10 +968,10 @@
     "IntegrationName": "OpenFeature",
     "SampleProjectName": "Samples.OpenFeature",
     "NugetPackageSearchName": "OpenFeature",
-    "MinVersion": "2.0.0",
+    "MinVersion": "2.3.0",
     "MaxVersionExclusive": "3.0.0",
     "SpecificVersions": [
-      "2.0.0",
+      "2.3.0",
       "2.10.0"
     ]
   }

tracer/build/nuget_version_cache.json

@@ -14257,7 +14257,8 @@
       "2.11.3",
       "2.11.8",
       "2.12.1",
-      "2.12.4"
+      "2.12.4",
+      "2.12.8"
     ]
   },
   {

tracer/build/supported_versions.json

@@ -258,7 +258,7 @@
         "name": "AWSSDK.DynamoDBv2",
         "minVersionAvailableInclusive": "3.1.0",
         "minVersionSupportedInclusive": "3.1.0",
-        "minVersionTestedInclusive": "3.1.5.3",
+        "minVersionTestedInclusive": "3.3.106.47",
         "maxVersionSupportedInclusive": "4.0.17.1",
         "maxVersionAvailableInclusive": "4.0.17.1",
         "maxVersionTestedInclusive": "4.0.17.1"
@@ -292,7 +292,7 @@
         "name": "AWSSDK.Kinesis",
         "minVersionAvailableInclusive": "3.1.0",
         "minVersionSupportedInclusive": "3.1.0",
-        "minVersionTestedInclusive": "3.1.3.5",
+        "minVersionTestedInclusive": "3.3.101.1",
         "maxVersionSupportedInclusive": "4.0.8.4",
         "maxVersionAvailableInclusive": "4.0.8.4",
         "maxVersionTestedInclusive": "4.0.8.4"
@@ -343,7 +343,7 @@
         "name": "AWSSDK.Core",
         "minVersionAvailableInclusive": "3.1.0",
         "minVersionSupportedInclusive": "3.1.0",
-        "minVersionTestedInclusive": "3.1.11",
+        "minVersionTestedInclusive": "3.3.107.40",
         "maxVersionSupportedInclusive": "4.0.3.21",
         "maxVersionAvailableInclusive": "4.0.3.21",
         "maxVersionTestedInclusive": "4.0.3.21"
@@ -360,7 +360,7 @@
         "name": "AWSSDK.SimpleNotificationService",
         "minVersionAvailableInclusive": "3.1.0",
         "minVersionSupportedInclusive": "3.1.0",
-        "minVersionTestedInclusive": "3.1.2.1",
+        "minVersionTestedInclusive": "3.3.102.17",
         "maxVersionSupportedInclusive": "4.0.2.20",
         "maxVersionAvailableInclusive": "4.0.2.20",
         "maxVersionTestedInclusive": "4.0.2.20"
@@ -377,7 +377,7 @@
         "name": "AWSSDK.SQS",
         "minVersionAvailableInclusive": "3.1.0",
         "minVersionSupportedInclusive": "3.1.0",
-        "minVersionTestedInclusive": "3.1.0.13",
+        "minVersionTestedInclusive": "3.3.103.26",
         "maxVersionSupportedInclusive": "4.0.2.18",
         "maxVersionAvailableInclusive": "4.0.2.18",
         "maxVersionTestedInclusive": "4.0.2.18"
@@ -886,7 +886,7 @@
         "name": "log4net",
         "minVersionAvailableInclusive": "1.2.10",
         "minVersionSupportedInclusive": "1.2.10",
-        "minVersionTestedInclusive": "1.2.11",
+        "minVersionTestedInclusive": "2.0.17",
         "maxVersionSupportedInclusive": "3.3.0",
         "maxVersionAvailableInclusive": "3.3.0",
         "maxVersionTestedInclusive": "3.3.0"
@@ -903,7 +903,7 @@
         "name": "MongoDB.Driver",
         "minVersionAvailableInclusive": "1.0.3744.30075",
         "minVersionSupportedInclusive": "2.1.0",
-        "minVersionTestedInclusive": "2.0.2",
+        "minVersionTestedInclusive": "2.30.0",
         "maxVersionSupportedInclusive": "3.7.1",
         "maxVersionAvailableInclusive": "3.7.1",
         "maxVersionTestedInclusive": "3.7.1"
@@ -920,7 +920,7 @@
         "name": "MongoDB.Driver",
         "minVersionAvailableInclusive": "1.0.3744.30075",
         "minVersionSupportedInclusive": "2.1.0",
-        "minVersionTestedInclusive": "2.0.2",
+        "minVersionTestedInclusive": "2.30.0",
         "maxVersionSupportedInclusive": "3.5.2",
         "maxVersionAvailableInclusive": "3.7.1",
         "maxVersionTestedInclusive": "3.7.1"
@@ -1059,7 +1059,7 @@
         "name": "NLog",
         "minVersionAvailableInclusive": "1.0.0.505",
         "minVersionSupportedInclusive": "1.0.0.505",
-        "minVersionTestedInclusive": "1.0.0.505",
+        "minVersionTestedInclusive": "4.7.15",
         "maxVersionSupportedInclusive": "6.1.1",
         "maxVersionAvailableInclusive": "6.1.1",
         "maxVersionTestedInclusive": "6.1.1"
@@ -1230,7 +1230,7 @@
         "name": "Serilog",
         "minVersionAvailableInclusive": "0.1.6",
         "minVersionSupportedInclusive": "1.0.1",
-        "minVersionTestedInclusive": "1.4.214",
+        "minVersionTestedInclusive": "2.12.0",
         "maxVersionSupportedInclusive": "4.3.1",
         "maxVersionAvailableInclusive": "4.3.1",
         "maxVersionTestedInclusive": "4.3.1"
@@ -1247,7 +1247,7 @@
         "name": "ServiceStack.Redis",
         "minVersionAvailableInclusive": "2.9.0",
         "minVersionSupportedInclusive": "4.0.2",
-        "minVersionTestedInclusive": "4.5.14",
+        "minVersionTestedInclusive": "6.1.0",
         "maxVersionSupportedInclusive": "10.0.6",
         "maxVersionAvailableInclusive": "10.0.6",
         "maxVersionTestedInclusive": "10.0.6"
@@ -1339,10 +1339,10 @@
         "name": "StackExchange.Redis",
         "minVersionAvailableInclusive": "1.0.187",
         "minVersionSupportedInclusive": "1.0.187",
-        "minVersionTestedInclusive": "1.0.488",
-        "maxVersionSupportedInclusive": "2.12.4",
-        "maxVersionAvailableInclusive": "2.12.4",
-        "maxVersionTestedInclusive": "2.12.4"
+        "minVersionTestedInclusive": "1.2.6",
+        "maxVersionSupportedInclusive": "2.12.8",
+        "maxVersionAvailableInclusive": "2.12.8",
+        "maxVersionTestedInclusive": "2.12.8"
       }
     ]
   },

tracer/dependabot/integrations/Datadog.Dependabot.StackExchange.Redis.csproj

@@ -8,8 +8,8 @@
   <ItemGroup>
     <!-- Integration: StackExchange.Redis -->
     <!--    Assembly: StackExchange.Redis -->
-    <!-- Latest package https://www.nuget.org/packages/StackExchange.Redis/2.12.4 -->
-    <PackageReference Include="StackExchange.Redis" Version="2.12.4" />
+    <!-- Latest package https://www.nuget.org/packages/StackExchange.Redis/2.12.8 -->
+    <PackageReference Include="StackExchange.Redis" Version="2.12.8" />
   </ItemGroup>
 
 </Project>

tracer/src/Datadog.FeatureFlags.OpenFeature/Datadog.FeatureFlags.OpenFeature.csproj

@@ -46,7 +46,7 @@
 
   <ItemGroup>
      <!-- If you update this version, be sure to update the TargetFrameworks element above-->
-    <PackageReference Include="OpenFeature" Version="2.0.0" />
+    <PackageReference Include="OpenFeature" Version="2.3.0" />
   </ItemGroup>
 
   <PropertyGroup>

tracer/src/Datadog.FeatureFlags.OpenFeature/DatadogProvider.cs

@@ -7,6 +7,7 @@
 
 using System;
 using System.Collections.Generic;
+using System.Collections.Immutable;
 using System.Linq;
 using System.Threading;
 using System.Threading.Channels;
@@ -20,15 +21,21 @@ namespace Datadog.FeatureFlags.OpenFeature;
 /// <summary>
 /// OpenFeature V2.0.0+ Provider for Datadog
 /// </summary>
-public sealed class DatadogProvider : global::OpenFeature.FeatureProvider
+public sealed class DatadogProvider : global::OpenFeature.FeatureProvider, IDisposable
 {
     private static Action? _onNewConfig = null;
-    private Metadata _metadata = new Metadata("datadog-openfeature-provider");
+    private readonly Metadata _metadata = new Metadata("datadog-openfeature-provider");
+#if NET6_0_OR_GREATER
+    private readonly FlagEvalMetricsHook _metricsHook;
+#endif
 
     /// <summary> Initializes a new instance of the <see cref="DatadogProvider"/> class. </summary>
     public DatadogProvider()
     {
         FeatureFlagsSdk.RegisterOnNewConfigEventHandler(() => SignalGeneralUpdate());
+#if NET6_0_OR_GREATER
+        _metricsHook = new FlagEvalMetricsHook();
+#endif
     }
 
     /// <summary> Gets a value indicating whether the Datadog's provider is instrumented and available  </summary>
@@ -126,4 +133,23 @@ public override Task<ResolutionDetails<Value>> ResolveStructureValueAsync(string
         var res = FeatureFlagsSdk.Resolve<Value>(flagKey, Trace.FeatureFlags.ValueType.Json, defaultValue, context);
         return Task.FromResult(res);
     }
+
+    /// <summary> Gets provider hooks for flag evaluation metrics tracking. </summary>
+    /// <returns> Returns the list of provider hooks. </returns>
+    public override IImmutableList<Hook> GetProviderHooks()
+    {
+#if NET6_0_OR_GREATER
+        return ImmutableList.Create<Hook>(_metricsHook);
+#else
+        return ImmutableList<Hook>.Empty;
+#endif
+    }
+
+    /// <inheritdoc/>
+    public void Dispose()
+    {
+#if NET6_0_OR_GREATER
+        _metricsHook.Dispose();
+#endif
+    }
 }

tracer/src/Datadog.FeatureFlags.OpenFeature/FlagEvalMetrics.cs

@@ -0,0 +1,90 @@
+// <copyright file="FlagEvalMetrics.cs" company="Datadog">
+// Unless explicitly stated otherwise all files in this repository are licensed under the Apache 2 License.
+// This product includes software developed at Datadog (https://www.datadoghq.com/). Copyright 2017 Datadog, Inc.
+// </copyright>
+
+#nullable enable
+
+#if NET6_0_OR_GREATER
+using System;
+using System.Collections.Generic;
+using System.Diagnostics.Metrics;
+
+namespace Datadog.FeatureFlags.OpenFeature;
+
+/// <summary>
+/// Manages OTel metric instruments for flag evaluation tracking.
+/// Uses System.Diagnostics.Metrics which is the standard .NET metrics API.
+/// </summary>
+internal sealed class FlagEvalMetrics : IDisposable
+{
+    internal const string MeterName = "Datadog.FeatureFlags.OpenFeature";
+    internal const string MetricName = "feature_flag.evaluations";
+    internal const string MetricUnit = "{evaluation}";
+    internal const string MetricDescription = "Number of feature flag evaluations";
+
+    internal const string TagFlagKey = "feature_flag.key";
+    internal const string TagVariant = "feature_flag.result.variant";
+    internal const string TagReason = "feature_flag.result.reason";
+    internal const string TagErrorType = "error.type";
+    internal const string TagAllocationKey = "feature_flag.result.allocation_key";
+
+    internal const string MetadataAllocationKey = "dd_allocationKey";
+
+    private readonly Meter _meter;
+    private readonly Counter<long> _counter;
+
+    /// <summary>
+    /// Initializes a new instance of the <see cref="FlagEvalMetrics"/> class.
+    /// </summary>
+    public FlagEvalMetrics()
+    {
+        _meter = new Meter(MeterName);
+        _counter = _meter.CreateCounter<long>(
+            MetricName,
+            unit: MetricUnit,
+            description: MetricDescription);
+    }
+
+    /// <summary>
+    /// Records a single flag evaluation metric with the specified attributes.
+    /// </summary>
+    /// <param name="flagKey">The flag key that was evaluated.</param>
+    /// <param name="variant">The resolved variant, or empty string if none.</param>
+    /// <param name="reason">The evaluation reason (e.g., "targeting_match", "error").</param>
+    /// <param name="errorType">The error type if reason is error, or null.</param>
+    /// <param name="allocationKey">The allocation key if available, or null.</param>
+    public void Record(
+        string flagKey,
+        string? variant,
+        string reason,
+        string? errorType,
+        string? allocationKey)
+    {
+        var tags = new List<KeyValuePair<string, object?>>
+        {
+            new(TagFlagKey, flagKey),
+            new(TagVariant, variant ?? string.Empty),
+            new(TagReason, reason)
+        };
+
+        if (!string.IsNullOrEmpty(errorType))
+        {
+            tags.Add(new(TagErrorType, errorType));
+        }
+
+        if (!string.IsNullOrEmpty(allocationKey))
+        {
+            tags.Add(new(TagAllocationKey, allocationKey));
+        }
+
+        _counter.Add(1, tags.ToArray());
+    }
+
+    /// <inheritdoc/>
+    public void Dispose()
+    {
+        _meter.Dispose();
+    }
+}
+#endif