Add Sampling Decision to Trace Envelope Header

CHANGELOG.md

@@ -2,9 +2,13 @@
 
 ## Unreleased
 
+### Features
+
+- Added Sampling Decision to Trace Envelope Header ([#2495](https://github.com/getsentry/sentry-dotnet/pull/2495))
+
 ### Fixes
 
-- Fixes baggage propagation when an exception is thrown from middleware ([#2487](https://github.com/getsentry/sentry-dotnet/pull/2487))
+- Fixed baggage propagation when an exception is thrown from middleware ([#2487](https://github.com/getsentry/sentry-dotnet/pull/2487))
 - Fix Durable Functions preventing orchestrators from completing ([#2491](https://github.com/getsentry/sentry-dotnet/pull/2491))
 - Re-enable HubTests.FlushOnDispose_SendsEnvelope ([#2492](https://github.com/getsentry/sentry-dotnet/pull/2492))
 

src/Sentry/DynamicSamplingContext.cs

@@ -22,6 +22,7 @@ internal class DynamicSamplingContext
     private DynamicSamplingContext(
         SentryId traceId,
         string publicKey,
+        bool? sampled,
         double sampleRate,
         string? release = null,
         string? environment = null,
@@ -51,6 +52,11 @@ private DynamicSamplingContext(
             ["sample_rate"] = sampleRate.ToString(CultureInfo.InvariantCulture)
         };
 
+        if (sampled.HasValue)
+        {
+            items.Add("sampled", sampled.Value ? "true" : "false");
+        }
+
         // Set optional values
         if (!string.IsNullOrWhiteSpace(release))
         {
@@ -95,6 +101,11 @@ private DynamicSamplingContext(
             return null;
         }
 
+        if (items.TryGetValue("sampled", out var sampledString) && !bool.TryParse(sampledString, out _))
+        {
+            return null;
+        }
+
         if (!items.TryGetValue("sample_rate", out var sampleRate) ||
             !double.TryParse(sampleRate, NumberStyles.Float, CultureInfo.InvariantCulture, out var rate) ||
             rate is < 0.0 or > 1.0)
@@ -110,6 +121,7 @@ public static DynamicSamplingContext CreateFromTransaction(TransactionTracer tra
         // These should already be set on the transaction.
         var publicKey = Dsn.Parse(options.Dsn!).PublicKey;
         var traceId = transaction.TraceId;
+        var sampled = transaction.IsSampled;
         var sampleRate = transaction.SampleRate!.Value;
         var userSegment = transaction.User.Segment;
         var transactionName = transaction.NameSource.IsHighQuality() ? transaction.Name : null;
@@ -121,6 +133,7 @@ public static DynamicSamplingContext CreateFromTransaction(TransactionTracer tra
         return new DynamicSamplingContext(
             traceId,
             publicKey,
+            sampled,
             sampleRate,
             release,
             environment,

src/Sentry/Internal/Hub.cs

@@ -172,7 +172,7 @@ internal ITransaction StartTransaction(
         }
 
         // Use the provided DSC, or create one based on this transaction.
-        // This must be done AFTER the sampling decision has been made.
+        // DSC creation must be done AFTER the sampling decision has been made.
         transaction.DynamicSamplingContext =
             dynamicSamplingContext ?? transaction.CreateDynamicSamplingContext(_options);
 

test/Sentry.Tests/DynamicSamplingContextTests.cs

@@ -1,3 +1,5 @@
+using Xunit.Sdk;
+
 namespace Sentry.Tests;
 
 public class DynamicSamplingContextTests
@@ -142,6 +144,22 @@ public void CreateFromBaggage_SampleRate_TooHigh()
         Assert.Null(dsc);
     }
 
+    [Fact]
+    public void CreateFromBaggage_Sampled_MalFormed()
+    {
+        var baggage = BaggageHeader.Create(new List<KeyValuePair<string, string>>
+        {
+            {"sentry-trace_id", "43365712692146d08ee11a729dfbcaca"},
+            {"sentry-public_key", "d4d82fc1c2c4032a83f3a29aa3a3aff"},
+            {"sentry-sample_rate", "1.0"},
+            {"sentry-sampled", "foo"},
+        });
+
+        var dsc = baggage.CreateDynamicSamplingContext();
+
+        Assert.Null(dsc);
+    }
+
     [Fact]
     public void CreateFromBaggage_Valid_Minimum()
     {
@@ -168,6 +186,7 @@ public void CreateFromBaggage_Valid_Complete()
         {
             {"sentry-trace_id", "43365712692146d08ee11a729dfbcaca"},
             {"sentry-public_key", "d4d82fc1c2c4032a83f3a29aa3a3aff"},
+            {"sentry-sampled", "true"},
             {"sentry-sample_rate", "1.0"},
             {"sentry-release", "test@1.0.0+abc"},
             {"sentry-environment", "production"},
@@ -178,9 +197,10 @@ public void CreateFromBaggage_Valid_Complete()
         var dsc = baggage.CreateDynamicSamplingContext();
 
         Assert.NotNull(dsc);
-        Assert.Equal(7, dsc.Items.Count);
+        Assert.Equal(baggage.Members.Count, dsc.Items.Count);
         Assert.Equal("43365712692146d08ee11a729dfbcaca", Assert.Contains("trace_id", dsc.Items));
         Assert.Equal("d4d82fc1c2c4032a83f3a29aa3a3aff", Assert.Contains("public_key", dsc.Items));
+        Assert.Equal("true", Assert.Contains("sampled", dsc.Items));
         Assert.Equal("1.0", Assert.Contains("sample_rate", dsc.Items));
         Assert.Equal("test@1.0.0+abc", Assert.Contains("release", dsc.Items));
         Assert.Equal("production", Assert.Contains("environment", dsc.Items));
@@ -210,8 +230,11 @@ public void ToBaggageHeader()
         Assert.Equal(original.Members, result.Members);
     }
 
-    [Fact]
-    public void CreateFromTransaction()
+    [Theory]
+    [InlineData(false)]
+    [InlineData(true)]
+    [InlineData(null)]
+    public void CreateFromTransaction(bool? isSampled)
     {
         var options = new SentryOptions
         {
@@ -230,7 +253,7 @@ public void CreateFromTransaction()
         {
             Name = "GET /person/{id}",
             NameSource = TransactionNameSource.Route,
-            IsSampled = true,
+            IsSampled = isSampled,
             SampleRate = 0.5,
             User =
             {
@@ -241,9 +264,17 @@ public void CreateFromTransaction()
         var dsc = transaction.CreateDynamicSamplingContext(options);
 
         Assert.NotNull(dsc);
-        Assert.Equal(7, dsc.Items.Count);
+        Assert.Equal(isSampled.HasValue ? 8 : 7, dsc.Items.Count);
         Assert.Equal(traceId.ToString(), Assert.Contains("trace_id", dsc.Items));
         Assert.Equal("d4d82fc1c2c4032a83f3a29aa3a3aff", Assert.Contains("public_key", dsc.Items));
+        if (transaction.IsSampled is { } sampled)
+        {
+            Assert.Equal(sampled ? "true" : "false", Assert.Contains("sampled", dsc.Items));
+        }
+        else
+        {
+            Assert.DoesNotContain("sampled", dsc.Items);
+        }
         Assert.Equal("0.5", Assert.Contains("sample_rate", dsc.Items));
         Assert.Equal("foo@2.4.5", Assert.Contains("release", dsc.Items));
         Assert.Equal("staging", Assert.Contains("environment", dsc.Items));

test/Sentry.Tests/EventProcessorTests.WithTransaction.verified.txt

@@ -1,4 +1,4 @@
-[
+[
   {
     Header: {
       event_id: Guid_1,
@@ -10,6 +10,7 @@
         public_key: d4d82fc1c2c4032a83f3a29aa3a3aff,
         release: release,
         sample_rate: 1,
+        sampled: true,
         trace_id: Guid_2,
         transaction: my transaction
       }

test/Sentry.Tests/HubTests.CaptureEvent_ActiveTransaction_UnhandledExceptionTransactionEndedAsCrashed.Core3_1.verified.txt

@@ -32,6 +32,7 @@
         public_key: d4d82fc1c2c4032a83f3a29aa3a3aff,
         release: release,
         sample_rate: 1,
+        sampled: true,
         trace_id: Guid_3,
         transaction: my transaction
       }
@@ -144,6 +145,7 @@
         public_key: d4d82fc1c2c4032a83f3a29aa3a3aff,
         release: release,
         sample_rate: 1,
+        sampled: true,
         trace_id: Guid_3,
         transaction: my transaction
       }

test/Sentry.Tests/HubTests.CaptureEvent_ActiveTransaction_UnhandledExceptionTransactionEndedAsCrashed.DotNet6_0.verified.txt

@@ -32,6 +32,7 @@
         public_key: d4d82fc1c2c4032a83f3a29aa3a3aff,
         release: release,
         sample_rate: 1,
+        sampled: true,
         trace_id: Guid_3,
         transaction: my transaction
       }
@@ -144,6 +145,7 @@
         public_key: d4d82fc1c2c4032a83f3a29aa3a3aff,
         release: release,
         sample_rate: 1,
+        sampled: true,
         trace_id: Guid_3,
         transaction: my transaction
       }

test/Sentry.Tests/HubTests.CaptureEvent_ActiveTransaction_UnhandledExceptionTransactionEndedAsCrashed.DotNet7_0.verified.txt

@@ -32,6 +32,7 @@
         public_key: d4d82fc1c2c4032a83f3a29aa3a3aff,
         release: release,
         sample_rate: 1,
+        sampled: true,
         trace_id: Guid_3,
         transaction: my transaction
       }
@@ -144,6 +145,7 @@
         public_key: d4d82fc1c2c4032a83f3a29aa3a3aff,
         release: release,
         sample_rate: 1,
+        sampled: true,
         trace_id: Guid_3,
         transaction: my transaction
       }

test/Sentry.Tests/HubTests.CaptureEvent_ActiveTransaction_UnhandledExceptionTransactionEndedAsCrashed.Mono4_0.verified.txt

@@ -32,6 +32,7 @@
         public_key: d4d82fc1c2c4032a83f3a29aa3a3aff,
         release: release,
         sample_rate: 1,
+        sampled: true,
         trace_id: Guid_3,
         transaction: my transaction
       }
@@ -144,6 +145,7 @@
         public_key: d4d82fc1c2c4032a83f3a29aa3a3aff,
         release: release,
         sample_rate: 1,
+        sampled: true,
         trace_id: Guid_3,
         transaction: my transaction
       }

test/Sentry.Tests/HubTests.CaptureEvent_ActiveTransaction_UnhandledExceptionTransactionEndedAsCrashed.Net4_8.verified.txt

@@ -32,6 +32,7 @@
         public_key: d4d82fc1c2c4032a83f3a29aa3a3aff,
         release: release,
         sample_rate: 1,
+        sampled: true,
         trace_id: Guid_3,
         transaction: my transaction
       }
@@ -144,6 +145,7 @@
         public_key: d4d82fc1c2c4032a83f3a29aa3a3aff,
         release: release,
         sample_rate: 1,
+        sampled: true,
         trace_id: Guid_3,
         transaction: my transaction
       }

test/Sentry.Tests/TransactionProcessorTests.Discard.verified.txt

@@ -1,4 +1,4 @@
-[
+[
   {
     Header: {
       event_id: Guid_1,
@@ -10,6 +10,7 @@
         public_key: d4d82fc1c2c4032a83f3a29aa3a3aff,
         release: release,
         sample_rate: 1,
+        sampled: true,
         trace_id: Guid_2,
         transaction: my transaction
       }

test/Sentry.Tests/TransactionProcessorTests.Simple.verified.txt

@@ -1,4 +1,4 @@
-[
+[
   {
     Header: {
       event_id: Guid_1,
@@ -10,6 +10,7 @@
         public_key: d4d82fc1c2c4032a83f3a29aa3a3aff,
         release: release,
         sample_rate: 1,
+        sampled: true,
         trace_id: Guid_2,
         transaction: my transaction
       }
@@ -51,6 +52,7 @@
         public_key: d4d82fc1c2c4032a83f3a29aa3a3aff,
         release: release,
         sample_rate: 1,
+        sampled: true,
         trace_id: Guid_2,
         transaction: my transaction
       }