Add NLog instrumentation for OpenTelemetry .NET Auto-Instrumentation

src/OpenTelemetry.AutoInstrumentation/.publicApi/net462/PublicAPI.Unshipped.txt

@@ -1,4 +1,6 @@
-OpenTelemetry.AutoInstrumentation.Instrumentations.NLog.Bridge.Integrations.LoggerIntegration
+OpenTelemetry.AutoInstrumentation.Instrumentations.NLog.TraceContextInjection.Integrations.WriteLogEventToTargetsIntegration
+OpenTelemetry.AutoInstrumentation.Instrumentations.NLog.TraceContextInjection.Integrations.WriteToTargetsIntegration
+OpenTelemetry.AutoInstrumentation.Instrumentations.NLog.TraceContextInjection.Integrations.WriteToTargetsLegacyIntegration
 OpenTelemetry.AutoInstrumentation.Instrumentations.NoCode.NoCodeIntegration0
 OpenTelemetry.AutoInstrumentation.Instrumentations.NoCode.NoCodeIntegration1
 OpenTelemetry.AutoInstrumentation.Instrumentations.NoCode.NoCodeIntegration2

src/OpenTelemetry.AutoInstrumentation/.publicApi/net8.0/PublicAPI.Unshipped.txt

@@ -1,4 +1,6 @@
-OpenTelemetry.AutoInstrumentation.Instrumentations.NLog.Bridge.Integrations.LoggerIntegration
+OpenTelemetry.AutoInstrumentation.Instrumentations.NLog.TraceContextInjection.Integrations.WriteLogEventToTargetsIntegration
+OpenTelemetry.AutoInstrumentation.Instrumentations.NLog.TraceContextInjection.Integrations.WriteToTargetsIntegration
+OpenTelemetry.AutoInstrumentation.Instrumentations.NLog.TraceContextInjection.Integrations.WriteToTargetsLegacyIntegration
 OpenTelemetry.AutoInstrumentation.Instrumentations.NoCode.NoCodeIntegration0
 OpenTelemetry.AutoInstrumentation.Instrumentations.NoCode.NoCodeIntegration1
 OpenTelemetry.AutoInstrumentation.Instrumentations.NoCode.NoCodeIntegration2

src/OpenTelemetry.AutoInstrumentation/Generated/net8.0/SourceGenerators/SourceGenerators.InstrumentationDefinitionsGenerator/InstrumentationDefinitions.g.cs

@@ -17,7 +17,7 @@ internal static partial class InstrumentationDefinitions
 {
     private static NativeCallTargetDefinition[] GetDefinitionsArray()
     {
-        var nativeCallTargetDefinitions = new List<NativeCallTargetDefinition>(40);
+        var nativeCallTargetDefinitions = new List<NativeCallTargetDefinition>(42);
         // Traces
         var tracerSettings = Instrumentation.TracerSettings.Value;
         if (tracerSettings.TracesEnabled)
@@ -108,7 +108,9 @@ private static NativeCallTargetDefinition[] GetDefinitionsArray()
             // NLog
             if (logSettings.EnabledInstrumentations.Contains(LogInstrumentation.NLog))
             {
-                nativeCallTargetDefinitions.Add(new("NLog", "NLog.Logger", "Log", ["System.Void", "NLog.LogEventInfo"], 5, 0, 0, 6, 65535, 65535, AssemblyFullName, "OpenTelemetry.AutoInstrumentation.Instrumentations.NLog.Bridge.Integrations.LoggerIntegration"));
+                nativeCallTargetDefinitions.Add(new("NLog", "NLog.Logger", "WriteLogEventToTargets", ["System.Void", "NLog.LogEventInfo", "NLog.Internal.ITargetWithFilterChain"], 6, 0, 0, 6, 65535, 65535, AssemblyFullName, "OpenTelemetry.AutoInstrumentation.Instrumentations.NLog.TraceContextInjection.Integrations.WriteLogEventToTargetsIntegration"));
+                nativeCallTargetDefinitions.Add(new("NLog", "NLog.Logger", "WriteToTargets", ["System.Void", "NLog.LogEventInfo", "NLog.Internal.ITargetWithFilterChain"], 5, 0, 0, 5, 65535, 65535, AssemblyFullName, "OpenTelemetry.AutoInstrumentation.Instrumentations.NLog.TraceContextInjection.Integrations.WriteToTargetsIntegration"));
+                nativeCallTargetDefinitions.Add(new("NLog", "NLog.Logger", "WriteToTargets", ["System.Void", "NLog.LogEventInfo", "NLog.Internal.TargetWithFilterChain"], 5, 0, 0, 5, 65535, 65535, AssemblyFullName, "OpenTelemetry.AutoInstrumentation.Instrumentations.NLog.TraceContextInjection.Integrations.WriteToTargetsLegacyIntegration"));
             }
         }
 

src/OpenTelemetry.AutoInstrumentation/Instrumentations/NLog/Bridge/OpenTelemetryLogHelpers.cs

@@ -148,10 +148,6 @@ private static BlockExpression BuildLogRecordAttributes(
         // If no parameterless constructor, try to find other constructors or use default for structs
         if (constructorInfo == null)
         {
-            var constructors = logRecordAttributesListType.GetConstructors();
-            Logger.Debug($"LogRecordAttributeList constructors: {string.Join(", ", constructors.Select(c => $"({string.Join(", ", c.GetParameters().Select(p => p.ParameterType.Name))})"))}");
-            Logger.Debug($"LogRecordAttributeList IsValueType: {logRecordAttributesListType.IsValueType}");
-
             // Try to find a constructor that takes an int (capacity)
             constructorInfo = logRecordAttributesListType.GetConstructor(new[] { typeof(int) });
             if (constructorInfo != null)
@@ -174,14 +170,15 @@ private static BlockExpression BuildLogRecordAttributes(
         }
 
         var addAttributeMethodInfo = logRecordAttributesListType.GetMethod("Add", new[] { typeof(string), typeof(object) })!;
+        var recordExceptionMethodInfo = logRecordAttributesListType.GetMethod("RecordException", BindingFlags.Instance | BindingFlags.Public)!;
 
         var expressions = new List<Expression> { assignInstanceVar };
 
-        // Add exception as an attribute if present
-        var addExceptionExpression = Expression.IfThen(
+        // Record exception using RecordException which adds exception.type, exception.message, exception.stacktrace
+        var recordExceptionExpression = Expression.IfThen(
             Expression.NotEqual(exception, Expression.Constant(null)),
-            Expression.Call(instanceVar, addAttributeMethodInfo, Expression.Constant("exception"), exception));
-        expressions.Add(addExceptionExpression);
+            Expression.Call(instanceVar, recordExceptionMethodInfo, exception));
+        expressions.Add(recordExceptionExpression);
 
         // Add custom properties if present
         var addPropertiesExpression = BuildAddPropertiesExpression(instanceVar, properties, addAttributeMethodInfo);
@@ -271,10 +268,7 @@ private static Expression BuildAddArgsExpression(ParameterExpression instanceVar
                 Expression.Call(
                     instanceVar,
                     addAttributeMethodInfo,
-                    Expression.Call(
-                        typeof(string).GetMethod("Concat", new[] { typeof(string), typeof(string) })!,
-                        Expression.Constant("arg_"),
-                        Expression.Call(indexVar, typeof(int).GetMethod("ToString", Type.EmptyTypes)!)),
+                    Expression.Call(indexVar, typeof(int).GetMethod("ToString", Type.EmptyTypes)!),
                     Expression.ArrayIndex(argsParam, indexVar)),
                 Expression.Assign(indexVar, Expression.Add(indexVar, Expression.Constant(1)))),
             breakLabel);