Add ActivitySource.CreateActivity methods (#48374)

* Add ActivitySource.CreateActivity methods

* Address the feedback

* Add IdFormat parameter to ActivitySource.Create and fix the whole IdFormat logic

* Address @noahfalk feedback

src/libraries/System.Diagnostics.DiagnosticSource/ref/System.Diagnostics.DiagnosticSourceActivity.cs

@@ -146,6 +146,9 @@ public sealed class ActivitySource : IDisposable
         public string Name { get { throw null; } }
         public string? Version { get { throw null; } }
         public bool HasListeners() { throw null; }
+        public System.Diagnostics.Activity? CreateActivity(string name, System.Diagnostics.ActivityKind kind) { throw null; }
+        public System.Diagnostics.Activity? CreateActivity(string name, System.Diagnostics.ActivityKind kind, System.Diagnostics.ActivityContext parentContext, System.Collections.Generic.IEnumerable<System.Collections.Generic.KeyValuePair<string, object?>>? tags = null, System.Collections.Generic.IEnumerable<System.Diagnostics.ActivityLink>? links = null, System.Diagnostics.ActivityIdFormat idFormat = System.Diagnostics.ActivityIdFormat.Unknown) { throw null; }
+        public System.Diagnostics.Activity? CreateActivity(string name, System.Diagnostics.ActivityKind kind, string parentId, System.Collections.Generic.IEnumerable<System.Collections.Generic.KeyValuePair<string, object?>>? tags = null, System.Collections.Generic.IEnumerable<System.Diagnostics.ActivityLink>? links = null, System.Diagnostics.ActivityIdFormat idFormat = System.Diagnostics.ActivityIdFormat.Unknown) { throw null; }
         public System.Diagnostics.Activity? StartActivity([System.Runtime.CompilerServices.CallerMemberName] string name = "", System.Diagnostics.ActivityKind kind = ActivityKind.Internal)  { throw null; }
         public System.Diagnostics.Activity? StartActivity(string name, System.Diagnostics.ActivityKind kind, System.Diagnostics.ActivityContext parentContext, System.Collections.Generic.IEnumerable<System.Collections.Generic.KeyValuePair<string, object?>>? tags = null, System.Collections.Generic.IEnumerable<System.Diagnostics.ActivityLink>? links = null, System.DateTimeOffset startTime = default) { throw null; }
         public System.Diagnostics.Activity? StartActivity(string name, System.Diagnostics.ActivityKind kind, string parentId, System.Collections.Generic.IEnumerable<System.Collections.Generic.KeyValuePair<string, object?>>? tags = null, System.Collections.Generic.IEnumerable<System.Diagnostics.ActivityLink>? links = null, System.DateTimeOffset startTime = default) { throw null; }

src/libraries/System.Diagnostics.DiagnosticSource/src/System/Diagnostics/Activity.cs

@@ -1007,55 +1007,15 @@ public void SetCustomProperty(string propertyName, object? propertyValue)
             return ret;
         }
 
-        internal static Activity CreateAndStart(ActivitySource source, string name, ActivityKind kind, string? parentId, ActivityContext parentContext,
-                                                IEnumerable<KeyValuePair<string, object?>>? tags, IEnumerable<ActivityLink>? links,
-                                                DateTimeOffset startTime, ActivityTagsCollection? samplerTags, ActivitySamplingResult request)
+        internal static Activity Create(ActivitySource source, string name, ActivityKind kind, string? parentId, ActivityContext parentContext,
+                                        IEnumerable<KeyValuePair<string, object?>>? tags, IEnumerable<ActivityLink>? links, DateTimeOffset startTime,
+                                        ActivityTagsCollection? samplerTags, ActivitySamplingResult request, bool startIt, ActivityIdFormat idFormat)
         {
             Activity activity = new Activity(name);
 
             activity.Source = source;
             activity.Kind = kind;
-
-            activity._previousActiveActivity = Current;
-            if (parentId != null)
-            {
-                activity._parentId = parentId;
-            }
-            else if (parentContext != default)
-            {
-                activity._traceId = parentContext.TraceId.ToString();
-
-                if (parentContext.SpanId != default)
-                {
-                    activity._parentSpanId = parentContext.SpanId.ToString();
-                }
-
-                activity.ActivityTraceFlags = parentContext.TraceFlags;
-                activity._traceState = parentContext.TraceState;
-            }
-            else
-            {
-                if (activity._previousActiveActivity != null)
-                {
-                    // The parent change should not form a loop. We are actually guaranteed this because
-                    // 1. Un-started activities can't be 'Current' (thus can't be 'parent'), we throw if you try.
-                    // 2. All started activities have a finite parent change (by inductive reasoning).
-                    activity.Parent = activity._previousActiveActivity;
-                }
-            }
-
-            activity.IdFormat =
-                ForceDefaultIdFormat ? DefaultIdFormat :
-                activity.Parent != null ? activity.Parent.IdFormat :
-                activity._parentSpanId != null ? ActivityIdFormat.W3C :
-                activity._parentId == null ? DefaultIdFormat :
-                IsW3CId(activity._parentId) ? ActivityIdFormat.W3C :
-                ActivityIdFormat.Hierarchical;
-
-            if (activity.IdFormat == ActivityIdFormat.W3C)
-                activity.GenerateW3CId();
-            else
-                activity._id = activity.GenerateHierarchicalId();
+            activity.IdFormat = idFormat;
 
             if (links != null)
             {
@@ -1091,8 +1051,6 @@ public void SetCustomProperty(string propertyName, object? propertyValue)
                 }
             }
 
-            activity.StartTimeUtc = startTime == default ? GetUtcNow() : startTime.UtcDateTime;
-
             activity.IsAllDataRequested = request == ActivitySamplingResult.AllData || request == ActivitySamplingResult.AllDataAndRecorded;
 
             if (request == ActivitySamplingResult.AllDataAndRecorded)
@@ -1100,7 +1058,32 @@ public void SetCustomProperty(string propertyName, object? propertyValue)
                 activity.ActivityTraceFlags |= ActivityTraceFlags.Recorded;
             }
 
-            SetCurrent(activity);
+            if (parentId != null)
+            {
+                activity._parentId = parentId;
+            }
+            else if (parentContext != default)
+            {
+                activity._traceId = parentContext.TraceId.ToString();
+
+                if (parentContext.SpanId != default)
+                {
+                    activity._parentSpanId = parentContext.SpanId.ToString();
+                }
+
+                activity.ActivityTraceFlags = parentContext.TraceFlags;
+                activity._traceState = parentContext.TraceState;
+            }
+
+            if (startTime != default)
+            {
+                activity.StartTimeUtc = startTime.UtcDateTime;
+            }
+
+            if (startIt)
+            {
+                activity.Start();
+            }
 
             return activity;
         }

src/libraries/System.Diagnostics.DiagnosticSource/src/System/Diagnostics/ActivityCreationOptions.cs

@@ -23,7 +23,8 @@ namespace System.Diagnostics
         /// <param name="kind"><see cref="ActivityKind"/> to create the Activity object with.</param>
         /// <param name="tags">Key-value pairs list for the tags to create the Activity object with.<see cref="ActivityContext"/></param>
         /// <param name="links"><see cref="ActivityLink"/> list to create the Activity object with.</param>
-        internal ActivityCreationOptions(ActivitySource source, string name, T parent, ActivityKind kind, IEnumerable<KeyValuePair<string, object?>>? tags, IEnumerable<ActivityLink>? links)
+        /// <param name="idFormat">The default Id format to use.</param>
+        internal ActivityCreationOptions(ActivitySource source, string name, T parent, ActivityKind kind, IEnumerable<KeyValuePair<string, object?>>? tags, IEnumerable<ActivityLink>? links, ActivityIdFormat idFormat)
         {
             Source = source;
             Name = name;
@@ -31,21 +32,49 @@ internal ActivityCreationOptions(ActivitySource source, string name, T parent, A
             Parent = parent;
             Tags = tags;
             Links = links;
+            IdFormat = idFormat;
+
+            if (IdFormat == ActivityIdFormat.Unknown && Activity.ForceDefaultIdFormat)
+            {
+                IdFormat = Activity.DefaultIdFormat;
+            }
 
             _samplerTags = null;
 
-            if (parent is ActivityContext ac)
+            if (parent is ActivityContext ac && ac != default)
             {
                 _context = ac;
+                if (IdFormat == ActivityIdFormat.Unknown)
+                {
+                    IdFormat = ActivityIdFormat.W3C;
+                }
             }
             else if (parent is string p && p != null)
             {
-                // We don't care about the return value. we care if _context is initialized accordingly.
-                ActivityContext.TryParse(p, null, out _context);
+                if (IdFormat != ActivityIdFormat.Hierarchical)
+                {
+                    if (ActivityContext.TryParse(p, null, out _context))
+                    {
+                        IdFormat = ActivityIdFormat.W3C;
+                    }
+
+                    if (IdFormat == ActivityIdFormat.Unknown)
+                    {
+                        IdFormat =ActivityIdFormat.Hierarchical;
+                    }
+                }
+                else
+                {
+                    _context = default;
+                }
             }
             else
             {
                 _context = default;
+                if (IdFormat == ActivityIdFormat.Unknown)
+                {
+                    IdFormat = Activity.Current != null ? Activity.Current.IdFormat : Activity.DefaultIdFormat;
+                }
             }
         }
 
@@ -103,16 +132,24 @@ public ActivityTraceId TraceId
 #endif
             get
             {
-                if (Parent is ActivityContext && _context == default)
+                if (Parent is ActivityContext && IdFormat == ActivityIdFormat.W3C && _context == default)
                 {
+                    Func<ActivityTraceId>? traceIdGenerator = Activity.TraceIdGenerator;
+                    ActivityTraceId id = traceIdGenerator == null ? ActivityTraceId.CreateRandom() : traceIdGenerator();
+
                     // Because the struct is readonly, we cannot directly assign _context. We have to workaround it by calling Unsafe.AsRef
-                    Unsafe.AsRef(in _context) = new ActivityContext(ActivityTraceId.CreateRandom(), default, ActivityTraceFlags.None);
+                    Unsafe.AsRef(in _context) = new ActivityContext(id, default, ActivityTraceFlags.None);
                 }
 
                 return _context.TraceId;
             }
         }
 
+        /// <summary>
+        /// Retrieve Id format of to use for the Activity we may create.
+        /// </summary>
+        internal ActivityIdFormat IdFormat { get; }
+
         // Helper to access the sampling tags. The SamplingTags Getter can allocate when not necessary.
         internal ActivityTagsCollection? GetSamplingTags() => _samplerTags;
 

src/libraries/System.Diagnostics.DiagnosticSource/src/System/Diagnostics/ActivitySource.cs

@@ -77,11 +77,56 @@ public bool HasListeners()
         /// <param name="name">The operation name of the Activity</param>
         /// <param name="kind">The <see cref="ActivityKind"/></param>
         /// <returns>The created <see cref="Activity"/> object or null if there is no any event listener.</returns>
+        /// <remarks>
+        /// If the Activity object is created, it will not start automatically. Callers need to call <see cref="Activity.Start()"/> to start it.
+        /// </remarks>
+        public Activity? CreateActivity(string name, ActivityKind kind)
+            => CreateActivity(name, kind, default, null, null, null, default, startIt: false);
+
+        /// <summary>
+        /// Creates a new <see cref="Activity"/> object if there is any listener to the Activity, returns null otherwise.
+        /// If the Activity object is created, it will not automatically start. Callers will need to call <see cref="Activity.Start()"/> to start it.
+        /// </summary>
+        /// <param name="name">The operation name of the Activity.</param>
+        /// <param name="kind">The <see cref="ActivityKind"/></param>
+        /// <param name="parentContext">The parent <see cref="ActivityContext"/> object to initialize the created Activity object with.</param>
+        /// <param name="tags">The optional tags list to initialize the created Activity object with.</param>
+        /// <param name="links">The optional <see cref="ActivityLink"/> list to initialize the created Activity object with.</param>
+        /// <param name="idFormat">The default Id format to use.</param>
+        /// <returns>The created <see cref="Activity"/> object or null if there is no any listener.</returns>
+        /// <remarks>
+        /// If the Activity object is created, it will not start automatically. Callers need to call <see cref="Activity.Start()"/> to start it.
+        /// </remarks>
+        public Activity? CreateActivity(string name, ActivityKind kind, ActivityContext parentContext, IEnumerable<KeyValuePair<string, object?>>? tags = null, IEnumerable<ActivityLink>? links = null, ActivityIdFormat idFormat = ActivityIdFormat.Unknown)
+            => CreateActivity(name, kind, parentContext, null, tags, links, default, startIt: false, idFormat);
+
+        /// <summary>
+        /// Creates a new <see cref="Activity"/> object if there is any listener to the Activity, returns null otherwise.
+        /// </summary>
+        /// <param name="name">The operation name of the Activity.</param>
+        /// <param name="kind">The <see cref="ActivityKind"/></param>
+        /// <param name="parentId">The parent Id to initialize the created Activity object with.</param>
+        /// <param name="tags">The optional tags list to initialize the created Activity object with.</param>
+        /// <param name="links">The optional <see cref="ActivityLink"/> list to initialize the created Activity object with.</param>
+        /// <param name="idFormat">The default Id format to use.</param>
+        /// <returns>The created <see cref="Activity"/> object or null if there is no any listener.</returns>
+        /// <remarks>
+        /// If the Activity object is created, it will not start automatically. Callers need to call <see cref="Activity.Start()"/> to start it.
+        /// </remarks>
+        public Activity? CreateActivity(string name, ActivityKind kind, string parentId, IEnumerable<KeyValuePair<string, object?>>? tags = null, IEnumerable<ActivityLink>? links = null, ActivityIdFormat idFormat = ActivityIdFormat.Unknown)
+            => CreateActivity(name, kind, default, parentId, tags, links, default, startIt: false, idFormat);
+
+        /// <summary>
+        /// Creates and starts a new <see cref="Activity"/> object if there is any listener to the Activity, returns null otherwise.
+        /// </summary>
+        /// <param name="name">The operation name of the Activity</param>
+        /// <param name="kind">The <see cref="ActivityKind"/></param>
+        /// <returns>The created <see cref="Activity"/> object or null if there is no any event listener.</returns>
         public Activity? StartActivity([CallerMemberName] string name = "", ActivityKind kind = ActivityKind.Internal)
-            => StartActivity(name, kind, default, null, null, null, default);
+            => CreateActivity(name, kind, default, null, null, null, default);
 
         /// <summary>
-        /// Creates a new <see cref="Activity"/> object if there is any listener to the Activity events, returns null otherwise.
+        /// Creates and starts a new <see cref="Activity"/> object if there is any listener to the Activity events, returns null otherwise.
         /// </summary>
         /// <param name="name">The operation name of the Activity.</param>
         /// <param name="kind">The <see cref="ActivityKind"/></param>
@@ -91,10 +136,10 @@ public bool HasListeners()
         /// <param name="startTime">The optional start timestamp to set on the created Activity object.</param>
         /// <returns>The created <see cref="Activity"/> object or null if there is no any listener.</returns>
         public Activity? StartActivity(string name, ActivityKind kind, ActivityContext parentContext, IEnumerable<KeyValuePair<string, object?>>? tags = null, IEnumerable<ActivityLink>? links = null, DateTimeOffset startTime = default)
-            => StartActivity(name, kind, parentContext, null, tags, links, startTime);
+            => CreateActivity(name, kind, parentContext, null, tags, links, startTime);
 
         /// <summary>
-        /// Creates a new <see cref="Activity"/> object if there is any listener to the Activity events, returns null otherwise.
+        /// Creates and starts a new <see cref="Activity"/> object if there is any listener to the Activity events, returns null otherwise.
         /// </summary>
         /// <param name="name">The operation name of the Activity.</param>
         /// <param name="kind">The <see cref="ActivityKind"/></param>
@@ -104,10 +149,10 @@ public bool HasListeners()
         /// <param name="startTime">The optional start timestamp to set on the created Activity object.</param>
         /// <returns>The created <see cref="Activity"/> object or null if there is no any listener.</returns>
         public Activity? StartActivity(string name, ActivityKind kind, string parentId, IEnumerable<KeyValuePair<string, object?>>? tags = null, IEnumerable<ActivityLink>? links = null, DateTimeOffset startTime = default)
-            => StartActivity(name, kind, default, parentId, tags, links, startTime);
+            => CreateActivity(name, kind, default, parentId, tags, links, startTime);
 
         /// <summary>
-        /// Creates a new <see cref="Activity"/> object if there is any listener to the Activity events, returns null otherwise.
+        /// Creates and starts a new <see cref="Activity"/> object if there is any listener to the Activity events, returns null otherwise.
         /// </summary>
         /// <param name="kind">The <see cref="ActivityKind"/></param>
         /// <param name="parentContext">The parent <see cref="ActivityContext"/> object to initialize the created Activity object with.</param>
@@ -117,9 +162,10 @@ public bool HasListeners()
         /// <param name="name">The operation name of the Activity.</param>
         /// <returns>The created <see cref="Activity"/> object or null if there is no any listener.</returns>
         public Activity? StartActivity(ActivityKind kind, ActivityContext parentContext = default, IEnumerable<KeyValuePair<string, object?>>? tags = null, IEnumerable<ActivityLink>? links = null, DateTimeOffset startTime = default, [CallerMemberName] string name = "")
-            => StartActivity(name, kind, parentContext, null, tags, links, startTime);
+            => CreateActivity(name, kind, parentContext, null, tags, links, startTime);
 
-        private Activity? StartActivity(string name, ActivityKind kind, ActivityContext context, string? parentId, IEnumerable<KeyValuePair<string, object?>>? tags, IEnumerable<ActivityLink>? links, DateTimeOffset startTime)
+        private Activity? CreateActivity(string name, ActivityKind kind, ActivityContext context, string? parentId, IEnumerable<KeyValuePair<string, object?>>? tags,
+                                            IEnumerable<ActivityLink>? links, DateTimeOffset startTime, bool startIt = true, ActivityIdFormat idFormat = ActivityIdFormat.Unknown)
         {
             // _listeners can get assigned to null in Dispose.
             SynchronizedList<ActivityListener>? listeners = _listeners;
@@ -135,8 +181,15 @@ public bool HasListeners()
 
             if (parentId != null)
             {
-                var aco = new ActivityCreationOptions<string>(this, name, parentId, kind, tags, links);
-                var acoContext = new ActivityCreationOptions<ActivityContext>(this, name, aco.GetContext(), kind, tags, links);
+                ActivityCreationOptions<string> aco = default;
+                ActivityCreationOptions<ActivityContext> acoContext = default;
+
+                aco = new ActivityCreationOptions<string>(this, name, parentId, kind, tags, links, idFormat);
+                if (aco.IdFormat == ActivityIdFormat.W3C)
+                {
+                    // acoContext is used only in the Sample calls which called only when we have W3C Id format.
+                    acoContext = new ActivityCreationOptions<ActivityContext>(this, name, aco.GetContext(), kind, tags, links, ActivityIdFormat.W3C);
+                }
 
                 listeners.EnumWithFunc((ActivityListener listener, ref ActivityCreationOptions<string> data, ref ActivitySamplingResult result, ref ActivityCreationOptions<ActivityContext> dataWithContext) => {
                     SampleActivity<string>? sampleUsingParentId = listener.SampleUsingParentId;
@@ -148,14 +201,14 @@ public bool HasListeners()
                             result = sr;
                         }
                     }
-                    else
+                    else if (data.IdFormat == ActivityIdFormat.W3C)
                     {
                         // In case we have a parent Id and the listener not providing the SampleUsingParentId, we'll try to find out if the following conditions are true:
                         //   - The listener is providing the Sample callback
                         //   - Can convert the parent Id to a Context. ActivityCreationOptions.TraceId != default means parent id converted to a valid context.
                         // Then we can call the listener Sample callback with the constructed context.
                         SampleActivity<ActivityContext>? sample = listener.Sample;
-                        if (sample != null && data.GetContext() != default) // data.GetContext() != default means parent Id parsed correctly to a context
+                        if (sample != null)
                         {
                             ActivitySamplingResult sr = sample(ref dataWithContext);
                             if (sr > result)
@@ -166,10 +219,18 @@ public bool HasListeners()
                     }
                 }, ref aco, ref samplingResult, ref acoContext);
 
-                if (context == default && aco.GetContext() != default)
+                if (context == default)
                 {
-                    context = aco.GetContext();
-                    parentId = null;
+                    if (aco.GetContext() != default)
+                    {
+                        context = aco.GetContext();
+                        parentId = null;
+                    }
+                    else if (acoContext.GetContext() != default)
+                    {
+                        context = acoContext.GetContext();
+                        parentId = null;
+                    }
                 }
 
                 samplerTags = aco.GetSamplingTags();
@@ -188,11 +249,13 @@ public bool HasListeners()
                         }
                     }
                 }
+
+                idFormat = aco.IdFormat;
             }
             else
             {
                 bool useCurrentActivityContext = context == default && Activity.Current != null;
-                var aco = new ActivityCreationOptions<ActivityContext>(this, name, useCurrentActivityContext ? Activity.Current!.Context : context, kind, tags, links);
+                var aco = new ActivityCreationOptions<ActivityContext>(this, name, useCurrentActivityContext ? Activity.Current!.Context : context, kind, tags, links, idFormat);
                 listeners.EnumWithFunc((ActivityListener listener, ref ActivityCreationOptions<ActivityContext> data, ref ActivitySamplingResult result, ref ActivityCreationOptions<ActivityContext> unused) => {
                     SampleActivity<ActivityContext>? sample = listener.Sample;
                     if (sample != null)
@@ -214,12 +277,12 @@ public bool HasListeners()
                 }
 
                 samplerTags = aco.GetSamplingTags();
+                idFormat = aco.IdFormat;
             }
 
             if (samplingResult != ActivitySamplingResult.None)
             {
-                activity = Activity.CreateAndStart(this, name, kind, parentId, context, tags, links, startTime, samplerTags, samplingResult);
-                listeners.EnumWithAction((listener, obj) => listener.ActivityStarted?.Invoke((Activity) obj), activity);
+                activity = Activity.Create(this, name, kind, parentId, context, tags, links, startTime, samplerTags, samplingResult, startIt, idFormat);
             }
 
             return activity;