Add start/stop OpCodes to SdkEventSource ActivityStart/Stop events

Renamed ActivityStarted/Stopped to ActivityStart/Stop
Add tests
Prevent concurrent execution of EventSource tests

src/OpenTelemetry/Internal/OpenTelemetrySdkEventSource.cs

@@ -69,7 +69,7 @@ public void ActivityStarted(Activity activity)
  // https:/dotnet/runtime/issues/61857
  var activityId = string.Concat("00-", activity.TraceId.ToHexString(), "-", activity.SpanId.ToHexString());
  activityId = string.Concat(activityId, activity.ActivityTraceFlags.HasFlag(ActivityTraceFlags.Recorded) ? "-01" : "-00");
- this.ActivityStarted(activity.DisplayName, activityId);
+ this.ActivityStart(activity.DisplayName, activityId);
  }
  }
 
@@ -78,7 +78,7 @@ public void ActivityStopped(Activity activity)
  {
  if (this.IsEnabled(EventLevel.Verbose, EventKeywords.All))
  {
- this.ActivityStopped(activity.DisplayName, activity.Id);
+ this.ActivityStop(activity.DisplayName, activity.Id);
  }
  }
 
@@ -175,14 +175,14 @@ public void ObservableInstrumentCallbackException(string exception)
  this.WriteEvent(16, exception);
  }
 
- [Event(24, Message = "Activity started. Name = '{0}', Id = '{1}'.", Level = EventLevel.Verbose)]
- public void ActivityStarted(string name, string id)
+ [Event(24, Message = "Activity started. Name = '{0}', Id = '{1}'.", Level = EventLevel.Verbose, Opcode = EventOpcode.Start)]
+ public void ActivityStart(string name, string id)
  {
  this.WriteEvent(24, name, id);
  }
 
- [Event(25, Message = "Activity stopped. Name = '{0}', Id = '{1}'.", Level = EventLevel.Verbose)]
- public void ActivityStopped(string name, string? id)
+ [Event(25, Message = "Activity stopped. Name = '{0}', Id = '{1}'.", Level = EventLevel.Verbose, Opcode = EventOpcode.Stop)]
+ public void ActivityStop(string name, string? id)
  {
  this.WriteEvent(25, name, id);
  }

test/Benchmarks/EventSourceBenchmarks.cs

@@ -17,7 +17,7 @@ public void EventWithIdAllocation()
  activity.Start();
  activity.Stop();
 
- OpenTelemetrySdkEventSource.Log.ActivityStarted(activity.OperationName, activity.Id);
+ OpenTelemetrySdkEventSource.Log.ActivityStart(activity.OperationName, activity.Id);
  }
 
  [Benchmark]

test/OpenTelemetry.Tests/EventSourceTest.cs

@@ -6,6 +6,7 @@
 
 namespace OpenTelemetry.Tests;
 
+[Collection("Uses-OpenTelemetrySdkEventSource")] // Prevent parallel execution with other tests that exercise the SdkEventSource
 public class EventSourceTest
 {
  [Fact]

test/OpenTelemetry.Tests/Internal/SdkEventSourceTest.cs

@@ -0,0 +1,121 @@
+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+#nullable enable
+
+using System.Diagnostics;
+using System.Diagnostics.Tracing;
+using OpenTelemetry.Internal;
+using OpenTelemetry.Trace;
+using Xunit;
+
+namespace OpenTelemetry.Tests.Internal;
+
+[Collection("Uses-OpenTelemetrySdkEventSource")] // Prevent parallel execution with other tests that exercise the SdkEventSource
+public class SdkEventSourceTest : IDisposable
+{
+ private readonly SdkEventListener listener = new();
+
+ public void Dispose()
+ {
+ this.listener.Dispose();
+ }
+
+ [Fact]
+ public void ActivityStartUsesOpCodeStart()
+ {
+ using (TracerProvider tracerProvider = Sdk.CreateTracerProviderBuilder()
+ .AddSource("TestSource")
+ .Build())
+ {
+ // Clear any events that were emitted during Build.
+ this.listener.Events.Clear();
+
+ const int numActivities = 4;
+
+ using ActivitySource activitySource = new("TestSource");
+ for (int i = 0; i < numActivities; i++)
+ {
+ using Activity? activity = activitySource.StartActivity($"Test Activity {i}");
+ }
+
+ // There should be 2 events for each activity: ActivityStart and ActivityStop.
+ Assert.Equal(numActivities * 2, this.listener.Events.Count);
+
+ HashSet<Guid> activityIds = [];
+ for (int i = 0; i < numActivities; i++)
+ {
+ EventWrittenEventArgs startEvent = this.listener.Events[i * 2];
+ EventWrittenEventArgs stopEvent = this.listener.Events[(i * 2) + 1];
+
+ Assert.Equal(nameof(OpenTelemetrySdkEventSource.ActivityStart), startEvent.EventName);
+ Assert.Equal(nameof(OpenTelemetrySdkEventSource.ActivityStop), stopEvent.EventName);
+
+ // Start and Stop should be matched on ActivityId.
+ Assert.Equal(startEvent.ActivityId, stopEvent.ActivityId);
+
+ // ActivityIds should be unique.
+ Assert.True(activityIds.Add(startEvent.ActivityId));
+ }
+ }
+ }
+
+ private sealed class SdkEventListener : EventListener
+ {
+ private static readonly string SdkEventSourceName = EventSource.GetName(typeof(OpenTelemetrySdkEventSource));
+ private readonly HashSet<EventSource> eventSourcesEnabled = [];
+
+ public List<EventWrittenEventArgs> Events { get; } = [];
+
+ public override void Dispose()
+ {
+ try
+ {
+ foreach (EventSource eventSource in this.eventSourcesEnabled)
+ {
+ this.DisableEvents(eventSource);
+ }
+ }
+ finally
+ {
+ base.Dispose();
+ }
+ }
+
+ protected override void OnEventSourceCreated(EventSource eventSource)
+ {
+ if (eventSource.Name == SdkEventSourceName)
+ {
+ this.eventSourcesEnabled.Add(eventSource);
+ this.EnableEvents(eventSource, EventLevel.Verbose, EventKeywords.All);
+ }
+ else if (eventSource.Name == "System.Threading.Tasks.TplEventSource")
+ {
+ // In addition to the OpenTelemetrySdkEventSource we need
+ // the TPL EventSource to enable activity tracking. When
+ // enabled and an EventSource writes events with
+ // EventOpCode.Start/Stop, then the ActivityTracker will
+ // generate new path-like ActivityIDs.
+ // Also note that activity tracking requires that the
+ // Start/Stop events are a matched pair, named like
+ // "xyzStart" and "xyzStop". ActivityTracker matches the
+ // stop event with the start event by recognizing those
+ // exact suffixes.
+ this.eventSourcesEnabled.Add(eventSource);
+ const EventKeywords taskFlowActivityIds = (EventKeywords)0x80;
+ this.EnableEvents(eventSource, EventLevel.Informational, taskFlowActivityIds);
+ }
+
+ base.OnEventSourceCreated(eventSource);
+ }
+
+ protected override void OnEventWritten(EventWrittenEventArgs eventData)
+ {
+ if (eventData.EventSource.Name == SdkEventSourceName)
+ {
+ this.Events.Add(eventData);
+ }
+
+ base.OnEventWritten(eventData);
+ }
+ }
+}

test/OpenTelemetry.Tests/Internal/SelfDiagnosticsEventListenerTest.cs

@@ -9,6 +9,7 @@
 
 namespace OpenTelemetry.Internal.Tests;
 
+[Collection("Uses-OpenTelemetrySdkEventSource")] // Prevent parallel execution with other tests that exercise the SdkEventSource
 public class SelfDiagnosticsEventListenerTest
 {
  private const string LOGFILEPATH = "Diagnostics.log";
@@ -32,7 +33,7 @@ public void SelfDiagnosticsEventListener_EventSourceSetup_LowerSeverity()
  _ = new SelfDiagnosticsEventListener(EventLevel.Error, configRefresher);
 
  // Emitting a Verbose event. Or any EventSource event with lower severity than Error.
- OpenTelemetrySdkEventSource.Log.ActivityStarted("Activity started", "1");
+ OpenTelemetrySdkEventSource.Log.ActivityStart("Activity started", "1");
  Assert.False(configRefresher.TryGetLogStreamCalled);
  }
 
@@ -115,7 +116,7 @@ public void SelfDiagnosticsEventListener_EmitEvent_OmitAsConfigured()
  _ = new SelfDiagnosticsEventListener(EventLevel.Error, configRefresher);
 
  // Act: emit an event with severity lower than configured
- OpenTelemetrySdkEventSource.Log.ActivityStarted("ActivityStart", "123");
+ OpenTelemetrySdkEventSource.Log.ActivityStart("ActivityStart", "123");
 
  // Assert
  Assert.False(configRefresher.TryGetLogStreamCalled);