feat: Include structured log message arguments as context data for MEL

src/Agent/NewRelic/Agent/Extensions/Providers/Wrapper/MicrosoftExtensionsLogging/MicrosoftLoggingWrapper.cs

@@ -26,6 +26,9 @@ public class MicrosoftLoggingWrapper : IWrapper
 
     private const string WrapperName = "MicrosoftLogging";
 
+    // This is defined here: https://github.com/dotnet/runtime/blob/54e4456b01060f54e5bb7d715e77e5f41bac558f/src/libraries/Microsoft.Extensions.Logging.Abstractions/src/LogValuesFormatter.cs#L233
+    private const string OriginalFormatKey = "{OriginalFormat}";
+
     public CanWrapResponse CanWrap(InstrumentedMethodInfo methodInfo)
     {
         return new CanWrapResponse(WrapperName.Equals(methodInfo.RequestedWrapperName));
@@ -58,14 +61,18 @@ private void RecordLogMessage(MethodCall methodCall, MEL.ILogger logger, IAgent
             Func<object, string> getLevelFunc = mc => ((MethodCall)mc).MethodArguments[0].ToString();
             Func<object, string> getRenderedMessageFunc = mc => ((MethodCall)mc).MethodArguments[2].ToString();
             Func<object, Exception> getLogExceptionFunc = mc => ((MethodCall)mc).MethodArguments[3] as Exception; // using "as" since we want a null if missing
-            Func<object, Dictionary<string, object>> getContextDataFunc = _ => GetContextData(logger, agent);
+
+            // MethodArguments[2] is the TState state parameter, which for structured logging
+            // typically implements IReadOnlyList<KeyValuePair<string, object?>>
+            var state = methodCall.MethodArguments[2];
+            Func<object, Dictionary<string, object>> getContextDataFunc = _ => GetContextData(logger, agent, state);
 
             var xapi = agent.GetExperimentalApi();
             xapi.RecordLogMessage(WrapperName, methodCall, getTimestampFunc, getLevelFunc, getRenderedMessageFunc, getLogExceptionFunc, getContextDataFunc, agent.TraceMetadata.SpanId, agent.TraceMetadata.TraceId);
         }
     }
 
-    private static Dictionary<string, object> GetContextData(MEL.ILogger logger, IAgent agent)
+    private static Dictionary<string, object> GetContextData(MEL.ILogger logger, IAgent agent, object state = null)
     {
         if (_contextDataNotSupported) // short circuit if we previously got an exception trying to access context data
         {
@@ -106,6 +113,35 @@ private static Dictionary<string, object> GetContextData(MEL.ILogger logger, IAg
                 // Possibly handle case of IEnumerable<KeyValuePair<object, object>>, etc (not now though)
             }, harvestedKvps);
 
+            // Extract structured log message arguments from the TState state parameter.
+            // For structured logging (e.g., _logger.LogInformation("User {UserId} did {Action}", userId, action)),
+            // MEL's FormattedLogValues implements IReadOnlyList<KeyValuePair<string, object?>> containing
+            // the individual named parameters. We merge these into context data so they appear as
+            // separate log attributes in New Relic (e.g., context.UserId, context.Action).
+            try
+            {
+                if (state is IEnumerable<KeyValuePair<string, object>> stateKvps)
+                {
+                    foreach (var kvp in stateKvps)
+                    {
+                        // Skip the "{OriginalFormat}" key — it's the message template string, not a parameter
+                        if (kvp.Key == OriginalFormatKey)
+                            continue;
+
+                        if (kvp.Value != null)
+                        {
+                            harvestedKvps[kvp.Key] = kvp.Value;
+                        }
+                    }
+                }
+            }
+            catch (Exception e)
+            {
+                // Log once and continue — state extraction is best-effort and should not
+                // prevent scope-based context data from being returned
+                agent.Logger.Log(Level.Finest, e, "Unable to extract structured log message arguments from state.");
+            }
+
             return harvestedKvps;
         }
         catch (Exception e)
@@ -135,4 +171,4 @@ private AfterWrappedMethodDelegate DecorateLogMessage(MEL.ILogger logger, IAgent
 
         return Delegates.GetDelegateFor(onComplete: () => handle?.Dispose());
     }
-}
+}

tests/Agent/IntegrationTests/IntegrationTests/Logging/ContextDataNotSupportedTests.cs

@@ -42,9 +42,9 @@ public ContextDataNotSupportedTestsBase(TFixture fixture, ITestOutputHelper outp
         string context = string.Join(",", _expectedAttributes.Select(x => x.Key + "=" + x.Value).ToArray());
 
         // should generate an exception message in the log since the dummy ILogger doesn't have the right properties
-        _fixture.AddCommand($"LoggingTester CreateSingleLogMessage {InfoMessage} INFO {context}");
+        _fixture.AddCommand($"LoggingTester CreateSingleLogMessage {InfoMessage} {context}");
         // do it again - this time, context data should be marked as unsupported and not generate an exception in the log
-        _fixture.AddCommand($"LoggingTester CreateSingleLogMessage {InfoMessage} INFO {context}");
+        _fixture.AddCommand($"LoggingTester CreateSingleLogMessage {InfoMessage} {context}");
 
         _fixture.AddActions
         (
@@ -105,4 +105,4 @@ public ContextDataNotSupportedNetCoreOldestTests(ConsoleDynamicMethodFixtureCore
         : base(fixture, output, LoggingFramework.DummyMEL)
     {
     }
-}
+}

tests/Agent/IntegrationTests/IntegrationTests/Logging/ContextDataTests.cs

@@ -43,7 +43,7 @@ public ContextDataTestsBase(TFixture fixture, ITestOutputHelper output, bool tes
         _loggingFrameworks.ForEach(x => _fixture.AddCommand($"LoggingTester SetFramework {x} {RandomPortGenerator.NextPort()}"));
         _fixture.AddCommand($"LoggingTester Configure");
 
-        _loggingFrameworks.ForEach(x => _fixture.AddCommand($"LoggingTester CreateSingleLogMessage {x} {InfoMessage} INFO {FlattenExpectedAttributes(GetExpectedAttributes(x))}"));
+        _loggingFrameworks.ForEach(x => _fixture.AddCommand($"LoggingTester CreateSingleLogMessageWithContext {x} {InfoMessage} {FlattenExpectedAttributes(GetExpectedAttributes(x))}"));
 
         if (_testNestedContexts) // on supported frameworks, ensure that we don't blow up when accumulating the context key/value pairs
             _fixture.AddCommand($"LoggingTester LogMessageInNestedScopes");
@@ -368,4 +368,4 @@ public NELContextDataCoreLatestTests(ConsoleDynamicMethodFixtureCoreLatest fixtu
     }
 }
 
-#endregion // NEL
+#endregion // NEL

tests/Agent/IntegrationTests/IntegrationTests/Logging/LocalDecorationTests.cs

@@ -41,7 +41,7 @@ public LocalDecorationTestsBase(TFixture fixture, ITestOutputHelper output, bool
         _fixture.AddCommand($"LoggingTester Configure{layoutType}LayoutAppenderForDecoration");
         if (logWithParam)
         {
-            _fixture.AddCommand($"LoggingTester CreateSingleLogMessageInTransactionWithParam {_testMessage}{"{@param}"}");
+            _fixture.AddCommand($"LoggingTester CreateSingleLogMessageInTransactionWithObjectParameter {_testMessage}{"{@param}"}");
         }
         else
         {
@@ -743,4 +743,4 @@ public NLogPatternLayoutDecorationDisabledTestsNetCoreOldestTests(ConsoleDynamic
 
 #endregion
 
-#endregion
+#endregion