Made sampling based on UserId configurable

CHANGELOG.md

@@ -3,7 +3,7 @@
 This changelog will be used to generate documentation on [release notes page](http://azure.microsoft.com/en-us/documentation/articles/app-insights-release-notes-dotnet/).
 
 ## Version 2.5.0-beta2
-
+- Turned off sampling based on UserId by default, made the use of this sample scoring configurable in the AdaptiveSamplingTelemetryProcessor
 
 ## Version 2.5.0-beta1
 - Method `Sanitize` on classes implementing `ITelemetry` no longer modifies the `TelemetryContext` fields. Serialized event json and ETW event will still have context tags sanitized.

PublicAPI/Microsoft.AI.ServerTelemetryChannel.dll/net45/PublicAPI.Unshipped.txt

@@ -0,0 +1,4 @@
+Microsoft.ApplicationInsights.WindowsServer.TelemetryChannel.AdaptiveSamplingTelemetryProcessor.AllowSamplingBasedOnUserId.get -> bool
+Microsoft.ApplicationInsights.WindowsServer.TelemetryChannel.AdaptiveSamplingTelemetryProcessor.AllowSamplingBasedOnUserId.set -> void
+Microsoft.ApplicationInsights.WindowsServer.TelemetryChannel.SamplingTelemetryProcessor.AllowSamplingBasedOnUserId.get -> bool
+Microsoft.ApplicationInsights.WindowsServer.TelemetryChannel.SamplingTelemetryProcessor.AllowSamplingBasedOnUserId.set -> void

PublicAPI/Microsoft.AI.ServerTelemetryChannel.dll/netstandard1.3/PublicAPI.Unshipped.txt

@@ -35,4 +35,8 @@ Microsoft.ApplicationInsights.WindowsServer.TelemetryChannel.ServerTelemetryChan
 Microsoft.ApplicationInsights.WindowsServer.TelemetryChannel.ServerTelemetryChannel.Send(Microsoft.ApplicationInsights.Channel.ITelemetry item) -> void
 Microsoft.ApplicationInsights.WindowsServer.TelemetryChannel.ServerTelemetryChannel.ServerTelemetryChannel() -> void
 Microsoft.ApplicationInsights.WindowsServer.TelemetryChannel.ServerTelemetryChannel.StorageFolder.get -> string
-Microsoft.ApplicationInsights.WindowsServer.TelemetryChannel.ServerTelemetryChannel.StorageFolder.set -> void
+Microsoft.ApplicationInsights.WindowsServer.TelemetryChannel.ServerTelemetryChannel.StorageFolder.set -> void
+Microsoft.ApplicationInsights.WindowsServer.TelemetryChannel.AdaptiveSamplingTelemetryProcessor.AllowSamplingBasedOnUserId.get -> bool
+Microsoft.ApplicationInsights.WindowsServer.TelemetryChannel.AdaptiveSamplingTelemetryProcessor.AllowSamplingBasedOnUserId.set -> void
+Microsoft.ApplicationInsights.WindowsServer.TelemetryChannel.SamplingTelemetryProcessor.AllowSamplingBasedOnUserId.get -> bool
+Microsoft.ApplicationInsights.WindowsServer.TelemetryChannel.SamplingTelemetryProcessor.AllowSamplingBasedOnUserId.set -> void

Test/ServerTelemetryChannel.Test/Shared.Tests/Implementation/SamplingScoreGeneratorTest.cs

@@ -27,8 +27,8 @@ public void SamplingScoreGeneratedUsingUserIdIfPresent()
             requestTelemetry.Context.User.Id = userId;
             requestTelemetry.Context.Operation.Id = GenerateRandomOperaitonId();
 
-            var eventTelemetrySamplingScore = SamplingScoreGenerator.GetSamplingScore(eventTelemetry);
-            var requestTelemetrySamplingScore = SamplingScoreGenerator.GetSamplingScore(requestTelemetry);
+            var eventTelemetrySamplingScore = SamplingScoreGenerator.GetSamplingScore(eventTelemetry, true);
+            var requestTelemetrySamplingScore = SamplingScoreGenerator.GetSamplingScore(requestTelemetry, true);
 
             Assert.AreEqual(eventTelemetrySamplingScore, requestTelemetrySamplingScore, 12);
         }
@@ -44,20 +44,46 @@ public void SamplingScoreGeneratedUsingOperationIdIfPresent()
             var requestTelemetry = new RequestTelemetry();
             requestTelemetry.Context.Operation.Id = operationId;
 
-            var eventTelemetrySamplingScore = SamplingScoreGenerator.GetSamplingScore(eventTelemetry);
-            var requestTelemetrySamplingScore = SamplingScoreGenerator.GetSamplingScore(requestTelemetry);
+            var eventTelemetrySamplingScore = SamplingScoreGenerator.GetSamplingScore(eventTelemetry, true);
+            var requestTelemetrySamplingScore = SamplingScoreGenerator.GetSamplingScore(requestTelemetry, true);
 
             Assert.AreEqual(eventTelemetrySamplingScore, requestTelemetrySamplingScore, 12);
         }
 
+        [TestMethod]
+        public void SamplingScoreGeneratedSkipsUserId()
+        {
+            string operationId = GenerateRandomOperaitonId();
+            string userId = GenerateRandomUserId();
+
+            var eventTelemetry = new EventTelemetry();
+            eventTelemetry.Context.Operation.Id = operationId;
+            eventTelemetry.Context.User.Id = userId;
+
+            var requestTelemetry = new RequestTelemetry();
+            requestTelemetry.Context.Operation.Id = operationId;
+            requestTelemetry.Context.User.Id = userId;
+
+            var eventTelemetrySamplingScore = SamplingScoreGenerator.GetSamplingScore(eventTelemetry, true);
+            var requestTelemetrySamplingScore = SamplingScoreGenerator.GetSamplingScore(requestTelemetry, true);
+
+            Assert.AreEqual(eventTelemetrySamplingScore, requestTelemetrySamplingScore, 12);
+
+            var eventTelemetrySamplingScoreNoUserConfig = SamplingScoreGenerator.GetSamplingScore(eventTelemetry, true);
+            var requestTelemetrySamplingScoreNoUserConfig = SamplingScoreGenerator.GetSamplingScore(requestTelemetry, true);
+
+            Assert.AreNotEqual(eventTelemetrySamplingScore, eventTelemetrySamplingScoreNoUserConfig);
+            Assert.AreNotEqual(requestTelemetrySamplingScore, requestTelemetrySamplingScoreNoUserConfig);
+        }
+
         [TestMethod]
         public void SamplingScoreIsRandomIfUserIdAndOperationIdAreNotPresent()
         {
             var eventTelemetry = new EventTelemetry();
             var traceTelemetry = new TraceTelemetry();
 
-            var eventTelemetrySamplingScore = SamplingScoreGenerator.GetSamplingScore(eventTelemetry);
-            var traceTelemetrySamplingScore = SamplingScoreGenerator.GetSamplingScore(traceTelemetry);
+            var eventTelemetrySamplingScore = SamplingScoreGenerator.GetSamplingScore(eventTelemetry, true);
+            var traceTelemetrySamplingScore = SamplingScoreGenerator.GetSamplingScore(traceTelemetry, true);
 
             Assert.AreNotEqual(eventTelemetrySamplingScore, traceTelemetrySamplingScore);
         }

src/ServerTelemetryChannel/Managed/Shared/AdaptiveSamplingTelemetryProcessor.cs

@@ -15,7 +15,7 @@ public class AdaptiveSamplingTelemetryProcessor : ITelemetryProcessor, IDisposab
         /// Fixed-rate sampling telemetry processor.
         /// </summary>
         private readonly SamplingTelemetryProcessor samplingProcessor;
-        
+
         /// <summary>
         /// Sampling percentage estimator settings.
         /// </summary>
@@ -220,6 +220,23 @@ public double MovingAverageRatio
             }
         }
 
+        /// <summary>
+        /// Gets or sets a value indicating whether to enable sample scoring for telemetry items based on the Context.User.Id flag. Default
+        /// is false.
+        /// </summary>
+        public bool AllowSamplingBasedOnUserId
+        {
+            get
+            {
+                return this.samplingProcessor.AllowSamplingBasedOnUserId;
+            }
+
+            set
+            {
+                this.samplingProcessor.AllowSamplingBasedOnUserId = value;
+            }
+        }
+
         /// <summary>
         /// Processes telemetry item.
         /// </summary>

src/ServerTelemetryChannel/Managed/Shared/Implementation/SamplingScoreGenerator.cs

@@ -13,12 +13,13 @@ internal static class SamplingScoreGenerator
         /// Generates telemetry sampling score between 0 and 100.
         /// </summary>
         /// <param name="telemetry">Telemetry item to score.</param>
+        /// <param name="allowUserId">Sampling score can be determined by using the Context.User.Id information, default is false.</param>
         /// <returns>Item sampling score.</returns>
-        public static double GetSamplingScore(ITelemetry telemetry)
+        public static double GetSamplingScore(ITelemetry telemetry, bool allowUserId = false)
         {
             double samplingScore = 0;
 
-            if (telemetry.Context.User.Id != null)
+            if (allowUserId && telemetry.Context.User.Id != null)
             {
                 samplingScore = (double)telemetry.Context.User.Id.GetSamplingHashCode() / int.MaxValue;
             }

src/ServerTelemetryChannel/Managed/Shared/SamplingTelemetryProcessor.cs

@@ -56,6 +56,7 @@ public SamplingTelemetryProcessor(ITelemetryProcessor next)
                 { RequestTelemetryName, typeof(RequestTelemetry) },
                 { TraceTelemetryName, typeof(TraceTelemetry) },
             };
+            this.AllowSamplingBasedOnUserId = false;
         }
 
         /// <summary>
@@ -124,6 +125,17 @@ public string IncludedTypes
             }
         }
 
+        /// <summary>
+        /// Gets or sets a value indicating whether or not we should calculate sampling based on the Context.User.Id field.
+        /// Default is false.
+        /// 
+        /// <remarks>
+        /// Calculation of the sampling score based on user_Id field is disabled by default to ensure successful correlation across many 
+        /// services on operation_Id field.
+        /// </remarks>
+        /// </summary>
+        public bool AllowSamplingBasedOnUserId { get; set; }
+
         /// <summary>
         /// Gets or sets data sampling percentage (between 0 and 100) for all <see cref="ITelemetry"/>
         /// objects logged in this <see cref="TelemetryClient"/>.
@@ -187,7 +199,7 @@ public void Process(ITelemetry item)
             //// Ok, now we can actually sample:
 
             samplingSupportingTelemetry.SamplingPercentage = samplingPercentage;
-            bool isSampledIn = SamplingScoreGenerator.GetSamplingScore(item) < samplingPercentage;
+            bool isSampledIn = SamplingScoreGenerator.GetSamplingScore(item, this.AllowSamplingBasedOnUserId) < samplingPercentage;
 
             if (isSampledIn)
             {