Ensure HTTP Response Status Code is searchable when using OTel (#4283)

Resolves #4094:
- #4094

Author: jamescrosswell

CHANGELOG.md

@@ -6,6 +6,7 @@
 
 - Added non-allocating `ConfigureScope` and `ConfigureScopeAsync` overloads ([#4244](https://github.com/getsentry/sentry-dotnet/pull/4244))
 - Add .NET MAUI `AutomationId` element information to breadcrumbs ([#4248](https://github.com/getsentry/sentry-dotnet/pull/4248))
+- The HTTP Response Status Code for spans instrumented using OpenTelemetry is now searchable ([#4283](https://github.com/getsentry/sentry-dotnet/pull/4283))
 
 ### Fixes
 

src/Sentry.OpenTelemetry/OpenTelemetryExtensions.cs

@@ -7,18 +7,21 @@ internal static class OpenTelemetryExtensions
 {
     public static SpanId AsSentrySpanId(this ActivitySpanId id) => SpanId.Parse(id.ToHexString());
 
-    public static ActivitySpanId AsActivitySpanId(this SpanId id) => ActivitySpanId.CreateFromString(id.ToString().AsSpan());
+    public static ActivitySpanId AsActivitySpanId(this SpanId id) =>
+        ActivitySpanId.CreateFromString(id.ToString().AsSpan());
 
     public static SentryId AsSentryId(this ActivityTraceId id) => SentryId.Parse(id.ToHexString());
 
-    public static ActivityTraceId AsActivityTraceId(this SentryId id) => ActivityTraceId.CreateFromString(id.ToString().AsSpan());
+    public static ActivityTraceId AsActivityTraceId(this SentryId id) =>
+        ActivityTraceId.CreateFromString(id.ToString().AsSpan());
 
-    public static BaggageHeader AsBaggageHeader(this IEnumerable<KeyValuePair<string, string?>> baggage, bool useSentryPrefix = false) =>
+    public static BaggageHeader AsBaggageHeader(this IEnumerable<KeyValuePair<string, string?>> baggage,
+        bool useSentryPrefix = false) =>
         BaggageHeader.Create(
             baggage.Where(member => member.Value != null)
-                        .Select(kvp => (KeyValuePair<string, string>)kvp!),
+                .Select(kvp => (KeyValuePair<string, string>)kvp!),
             useSentryPrefix
-            );
+        );
 
     /// <summary>
     /// The names that OpenTelemetry gives to attributes, by convention, have changed over time so we often need to
@@ -40,18 +43,29 @@ public static BaggageHeader AsBaggageHeader(this IEnumerable<KeyValuePair<string
                 return value;
             }
         }
+
         return default;
     }
 
     public static string? HttpMethodAttribute(this IDictionary<string, object?> attributes) =>
         attributes.GetFirstMatchingAttribute<string>(
             OtelSemanticConventions.AttributeHttpRequestMethod,
             OtelSemanticConventions.AttributeHttpMethod // Fallback pre-1.5.0
-            );
+        );
 
     public static string? UrlFullAttribute(this IDictionary<string, object?> attributes) =>
         attributes.GetFirstMatchingAttribute<string>(
             OtelSemanticConventions.AttributeUrlFull,
             OtelSemanticConventions.AttributeHttpUrl // Fallback pre-1.5.0
-            );
+        );
+
+    public static short? HttpResponseStatusCodeAttribute(this IDictionary<string, object?> attributes)
+    {
+        var statusCode = attributes.GetFirstMatchingAttribute<int?>(
+            OtelSemanticConventions.AttributeHttpResponseStatusCode
+        );
+        return statusCode is >= short.MinValue and <= short.MaxValue
+            ? (short)statusCode.Value
+            : null;
+    }
 }

src/Sentry.OpenTelemetry/SentrySpanProcessor.cs

@@ -230,10 +230,16 @@ public override void OnEnd(Activity data)
         span.Operation = operation;
         span.Description = description;
 
+        // Handle HTTP response status code specially
+        var statusCode = attributes.HttpResponseStatusCodeAttribute();
         if (span is TransactionTracer transaction)
         {
             transaction.Name = description;
             transaction.NameSource = source;
+            if (statusCode is { } responseStatusCode)
+            {
+                transaction.Contexts.Response.StatusCode = responseStatusCode;
+            }
 
             // Use the end timestamp from the activity data.
             transaction.EndTimestamp = data.StartTimeUtc + data.Duration;
@@ -250,6 +256,11 @@ public override void OnEnd(Activity data)
             // Resource attributes do not need to be set, as they would be identical as those set on the transaction.
             spanTracer.SetExtras(attributes);
             spanTracer.SetExtra("otel.kind", data.Kind);
+            if (statusCode is { } responseStatusCode)
+            {
+                // Set this as a tag so that it's searchable in Sentry
+                span.SetTag(OtelSemanticConventions.AttributeHttpResponseStatusCode, responseStatusCode.ToString());
+            }
         }
 
         // In ASP.NET Core the middleware finishes up (and the scope gets popped) before the activity is ended.  So we

test/Sentry.OpenTelemetry.Tests/SentrySpanProcessorTests.cs

@@ -429,6 +429,117 @@ public void OnEnd_Unsampled_Span_DoesNotThrow()
         // UnsampledSpan.Finish() is basically a no-op.
     }
 
+    [Fact]
+    public void OnEnd_Transaction_SetsResponseStatusCode()
+    {
+        // Arrange
+        _fixture.Options.Instrumenter = Instrumenter.OpenTelemetry;
+        var sut = _fixture.GetSut();
+
+        var tags = new Dictionary<string, object> {
+            { OtelSemanticConventions.AttributeHttpResponseStatusCode, 404 }
+        };
+        var data = Tracer.StartActivity(
+            name: "test operation",
+            kind: ActivityKind.Server,
+            parentContext: default,
+            tags
+        );
+        sut.OnStart(data);
+
+        sut._map.TryGetValue(data.SpanId, out var span);
+
+        // Act
+        sut.OnEnd(data);
+
+        // Assert
+        if (span is not TransactionTracer transaction)
+        {
+            Assert.Fail("Span is not a transaction tracer");
+            return;
+        }
+
+        using (new AssertionScope())
+        {
+            transaction.Contexts.Response.StatusCode.Should().Be(404);
+        }
+    }
+
+    [Fact]
+    public void OnEnd_Transaction_DoesNotClearResponseStatusCode()
+    {
+        // Arrange
+        _fixture.Options.Instrumenter = Instrumenter.OpenTelemetry;
+        var sut = _fixture.GetSut();
+
+        var data = Tracer.StartActivity(
+            name: "test operation",
+            kind: ActivityKind.Server,
+            parentContext: default,
+            new Dictionary<string, object>()
+        );
+        sut.OnStart(data);
+
+        sut._map.TryGetValue(data.SpanId, out var span);
+        (span as TransactionTracer)!.Contexts.Response.StatusCode = 200;
+
+        // Act
+        sut.OnEnd(data);
+
+        // Assert
+        if (span is not TransactionTracer transaction)
+        {
+            Assert.Fail("Span is not a transaction tracer");
+            return;
+        }
+
+        using (new AssertionScope())
+        {
+            transaction.Contexts.Response.StatusCode.Should().Be(200);
+        }
+    }
+
+    [Fact]
+    public void OnEnd_Span_SetsResponseStatusCode()
+    {
+        // Arrange
+        _fixture.Options.Instrumenter = Instrumenter.OpenTelemetry;
+        var sut = _fixture.GetSut();
+
+        var parent = Tracer.StartActivity(name: "transaction")!;
+        sut.OnStart(parent);
+
+        var tags = new Dictionary<string, object> {
+            { OtelSemanticConventions.AttributeHttpResponseStatusCode, 404 }
+        };
+        var data = Tracer.StartActivity(
+            name: "test operation",
+            kind: ActivityKind.Server,
+            parentContext: default,
+            tags
+        );
+        sut.OnStart(data);
+
+        sut._map.TryGetValue(data.SpanId, out var span);
+
+        // Act
+        sut.OnEnd(data);
+
+        // Assert
+        if (span is not SpanTracer spanTracer)
+        {
+            Assert.Fail("Span is not a span tracer");
+            return;
+        }
+
+        using (new AssertionScope())
+        {
+            spanTracer.Tags.TryGetValue(OtelSemanticConventions.AttributeHttpResponseStatusCode,
+                    out var responseStatusCode).Should().BeTrue();
+            responseStatusCode.Should().Be("404");
+        }
+    }
+
     [Fact]
     public void OnEnd_Transaction_RestoresSavedScope()
     {