Implement DroppedSpanStats (#1511)

* Implement DroppedSpanStats

* Dropped spans: calculate destination for dropped spans stats

* Update Transaction.cs

Introduce DroppedSpanStatsKey

* Update Transaction.cs

* Update DroppedSpansStatsTests.cs

* Do not create Span.Context for dropped spans

* Update ExitSpanTests.cs

* Update Span.cs

* Remove obsolete fields

* Update DroppedSpansStats.cs

* Generate less spans in Transaction_And_Spans_Captured_When_Large_Request

* Update HttpContextCurrentExecutionSegmentsContainerTests.cs

* Adapt test - remove unused fields

sample/AspNetFullFrameworkSampleApp/Controllers/DatabaseController.cs

@@ -107,16 +107,16 @@ public async Task<ActionResult> Bulk(IEnumerable<CreateSampleDataViewModel> mode
 				return JsonBadRequest(new { success = false, message = "Invalid samples" });
 
 			var sampleData = model.Select(m => new SampleData { Name = m.Name });
+
+			var aggregatedModel = new SampleData { Name = model.Aggregate("", (current, next) => current + ", " + next.Name) };
 			int changes;
 
 			using (var context = new SampleDataDbContext())
-			using (var transaction = context.Database.BeginTransaction())
 			{
 				context.Configuration.AutoDetectChangesEnabled = false;
 				context.Configuration.ValidateOnSaveEnabled = false;
-				context.Set<SampleData>().AddRange(sampleData);
+				context.Set<SampleData>().Add(aggregatedModel);
 				changes = await context.SaveChangesAsync();
-				transaction.Commit();
 			}
 
 			return Json(new { success = true, changes });

src/Elastic.Apm.Azure.ServiceBus/AzureMessagingServiceBusDiagnosticListener.cs

@@ -1,4 +1,4 @@
-// Licensed to Elasticsearch B.V under
+// Licensed to Elasticsearch B.V under
 // one or more agreements.
 // Elasticsearch B.V licenses this file to you under the Apache 2.0 License.
 // See the LICENSE file in the project root for more information
@@ -252,9 +252,7 @@ private void OnSendStart(KeyValuePair<string, object> kv, string action)
 				Address = destinationAddress,
 				Service = new Destination.DestinationService
 				{
-					Name = ServiceBus.SubType,
-					Resource = queueName is null ? ServiceBus.SubType : $"{ServiceBus.SubType}/{queueName}",
-					Type = ApiConstants.TypeMessaging
+					Resource = queueName is null ? ServiceBus.SubType : $"{ServiceBus.SubType}/{queueName}"
 				}
 			};
 

src/Elastic.Apm.Azure.ServiceBus/MicrosoftAzureServiceBusDiagnosticListener.cs

@@ -1,4 +1,4 @@
-// Licensed to Elasticsearch B.V under
+// Licensed to Elasticsearch B.V under
 // one or more agreements.
 // Elasticsearch B.V licenses this file to you under the Apache 2.0 License.
 // See the LICENSE file in the project root for more information
@@ -236,9 +236,7 @@ private void OnSendStart(KeyValuePair<string, object> kv, string action, Propert
 				Address = destinationAddress?.AbsoluteUri,
 				Service = new Destination.DestinationService
 				{
-					Name = ServiceBus.SubType,
-					Resource = queueName is null ? ServiceBus.SubType : $"{ServiceBus.SubType}/{queueName}",
-					Type = ApiConstants.TypeMessaging
+					Resource = queueName is null ? ServiceBus.SubType : $"{ServiceBus.SubType}/{queueName}"
 				}
 			};
 

src/Elastic.Apm.GrpcClient/GrpcClientDiagnosticListener.cs

@@ -64,7 +64,7 @@ protected override void HandleOnNext(KeyValuePair<string, object> kv)
 					span.Outcome = GrpcHelper.GrpcClientReturnCodeToOutcome(GrpcHelper.GrpcReturnCodeToString(grpcStatusCode));
 
 				span.Context.Destination = UrlUtils.ExtractDestination(requestObject.RequestUri, Logger);
-				span.Context.Destination.Service = UrlUtils.ExtractService(requestObject.RequestUri, span);
+				span.Context.Destination.Service = new() { Resource = UrlUtils.ExtractService(requestObject.RequestUri, span) };
 
 				span.End();
 			}

src/Elastic.Apm/DiagnosticListeners/HttpDiagnosticListenerImplBase.cs

@@ -194,7 +194,10 @@ private void ProcessStartEvent(TRequest request, Uri requestUrl)
 			if (span is Span realSpan)
 			{
 				if (!realSpan.ShouldBeSentToApmServer)
+				{
+					realSpan.ServiceResource =  UrlUtils.ExtractService(requestUrl, realSpan);
 					return;
+				}
 			}
 
 			span.Context.Http = new Http { Method = method };

src/Elastic.Apm/Helpers/UrlUtils.cs

@@ -33,7 +33,6 @@ internal static Destination ExtractDestination(Uri url, IApmLogger logger)
 			return new Destination { Address = host, Port = url.Port == -1 ? (int?)null : url.Port };
 		}
 
-		internal static Destination.DestinationService ExtractService(Uri url, ISpan span) =>
-			new() { Resource = $"{url.Host}:{url.Port}" };
+		internal static string ExtractService(Uri url, ISpan span) => $"{url.Host}:{url.Port}";
 	}
 }

src/Elastic.Apm/Model/DbSpanCommon.cs

@@ -50,13 +50,13 @@ internal void EndSpan(ISpan span, IDbCommand dbCommand, Outcome outcome, TimeSpa
 				{
 					capturedSpan.Context.Db = new Database
 					{
-						Statement = GetDbSpanName(dbCommand),
-						Instance = dbCommand.Connection.Database,
-						Type = Database.TypeSql
+						Statement = GetDbSpanName(dbCommand), Instance = dbCommand.Connection.Database, Type = Database.TypeSql
 					};
 
 					capturedSpan.Context.Destination = GetDestination(dbCommand.Connection?.ConnectionString, defaultPort);
 				}
+				else
+					capturedSpan.ServiceResource =  !string.IsNullOrEmpty(capturedSpan.Subtype) ? capturedSpan.Subtype : Database.TypeSql + dbCommand.Connection.Database;
 
 				capturedSpan.Outcome = outcome;
 			}

src/Elastic.Apm/Model/DroppedSpanStats.cs

@@ -0,0 +1,52 @@
+// Licensed to Elasticsearch B.V under
+// one or more agreements.
+// Elasticsearch B.V licenses this file to you under the Apache 2.0 License.
+// See the LICENSE file in the project root for more information
+
+using Elastic.Apm.Api;
+using Elastic.Apm.Libraries.Newtonsoft.Json;
+
+namespace Elastic.Apm.Model
+{
+	/// <summary>
+	/// DroppedSpanStats holds information about spans that were dropped (for example due to transaction_max_spans or
+	/// exit_span_min_duration).
+	/// </summary>
+	internal class DroppedSpanStats
+	{
+		public DroppedSpanStats(string destinationServiceResource, Outcome outcome, double durationSumUs)
+		{
+			DurationCount = 1;
+			DestinationServiceResource = destinationServiceResource;
+			Outcome = outcome;
+			DurationSumUs = durationSumUs;
+		}
+
+		/// <summary>
+		/// DestinationServiceResource identifies the destination service resource being operated on. e.g. 'http://elastic.co:80',
+		/// 'elasticsearch', 'rabbitmq/queue_name'.
+		/// </summary>
+		[JsonProperty("destination_service_resource")]
+		public string DestinationServiceResource { get; }
+
+		/// <summary>
+		/// Duration holds duration aggregations about the dropped span.
+		/// Count holds the number of times the dropped span happened.
+		/// </summary>
+		[JsonProperty("duration.count")]
+		public int DurationCount { get; set; }
+
+
+		/// <summary>
+		/// Duration holds duration aggregations about the dropped span.
+		/// Sum holds dimensions about the dropped span's duration.
+		/// </summary>
+		[JsonProperty("duration.sum.us")]
+		public double DurationSumUs { get; set; }
+
+		/// <summary>
+		/// Outcome of the aggregated spans.
+		/// </summary>
+		public Outcome Outcome { get; }
+	}
+}

src/Elastic.Apm/Model/Span.cs

@@ -132,6 +132,14 @@ public Span(
 		[MaxLength]
 		public string Action { get; set; }
 
+		/// <summary>
+		/// Stores Context.Destination.Service.Resource on the top level.
+		/// With this field, we can set Resource for dropped spans without instantiating Context.
+		/// Only set for dropped spans.
+		/// </summary>
+		[JsonIgnore]
+		public string ServiceResource { get; set; }
+
 		[JsonIgnore]
 		internal IConfiguration Configuration => _enclosingTransaction.Configuration;
 
@@ -362,17 +370,20 @@ public void End()
 			else
 				_enclosingTransaction.SpanTimings.TryAdd(new SpanTimerKey(Type, Subtype), new SpanTimer(SelfDuration));
 
-			if (ShouldBeSentToApmServer && isFirstEndCall)
+			try
 			{
-				try
-				{
-					DeduceDestination();
-				}
-				catch (Exception e)
-				{
-					_logger.Warning()?.LogException(e, "Failed deducing destination fields for span.");
-				}
+				DeduceDestination();
+			}
+			catch (Exception e)
+			{
+				_logger.Warning()?.LogException(e, "Failed deducing destination fields for span.");
+			}
 
+			if (_isDropped && (!string.IsNullOrEmpty(ServiceResource) || (_context.IsValueCreated &&  Context?.Destination?.Service?.Resource != null)))
+				_enclosingTransaction.UpdateDroppedSpanStats(ServiceResource ?? Context?.Destination?.Service?.Resource, _outcome, Duration.Value);
+
+			if (ShouldBeSentToApmServer && isFirstEndCall)
+			{
 				// Spans are sent only for sampled transactions so it's only worth capturing stack trace for sampled spans
 				// ReSharper disable once CompareOfFloatsByEqualityOperator
 				if (Configuration.StackTraceLimit != 0 && Configuration.SpanFramesMinDurationInMilliseconds != 0 && RawStackTrace == null
@@ -455,6 +466,13 @@ private void DeduceDestination()
 			if (!IsExitSpan)
 				return;
 
+			if (!_context.IsValueCreated)
+			{
+				if(string.IsNullOrEmpty(ServiceResource))
+					ServiceResource = !string.IsNullOrEmpty(Subtype) ? Subtype : Type;
+				return;
+			}
+
 			if (Context.Http != null)
 			{
 				var destination = DeduceHttpDestination();
@@ -489,7 +507,7 @@ void FillDestinationService()
 				else if (Context.Http?.Url != null)
 				{
 					if (!string.IsNullOrEmpty(_context?.Value?.Http?.Url))
-						Context.Destination.Service = UrlUtils.ExtractService(_context.Value.Http.OriginalUrl, this);
+						Context.Destination.Service = new() { Resource = UrlUtils.ExtractService(_context.Value.Http.OriginalUrl, this) };
 					else
 						Context.Destination.Service.Resource = !string.IsNullOrEmpty(Subtype) ? Subtype : Type;
 				}