fix(otel logging): Include ILogger CategoryName in logger output

sdk/monitor/Azure.Monitor.OpenTelemetry.AspNetCore/CHANGELOG.md

@@ -8,6 +8,11 @@
 
 ### Bugs Fixed
 
+* Added the `LogRecord.CategoryName` field to log and exception telemetry.
+  Previously the `CategoryName` field was omitted, which was inconsistent with
+  expected `ILogger` behavior, and with Application Insights classic behavior.
+  ([#44754](https://github.com/Azure/azure-sdk-for-net/pull/44754))
+
 * Fixed an issue where a `DuplicateKeyException` could be thrown if `EventId`
   and `EventName` were present in both `LogRecord` (`LogRecord.EventId`,
   `LogRecord.EventName`) and `LogRecord.Attributes`. The method now uses

sdk/monitor/Azure.Monitor.OpenTelemetry.AspNetCore/src/LiveMetrics/DataCollection/DocumentHelper.cs

@@ -293,6 +293,13 @@ internal static ExceptionDocument ConvertToExceptionDocument(LogRecord logRecord
 
             int propertiesCount = 0;
 
+            var categoryName = logRecord.CategoryName;
+            if (!string.IsNullOrEmpty(categoryName))
+            {
+                exceptionDocument.Properties.Add(new KeyValuePairString("CategoryName", categoryName));
+                propertiesCount++;
+            }
+
             foreach (KeyValuePair<string, object?> item in logRecord.Attributes ?? Enumerable.Empty<KeyValuePair<string, object?>>())
             {
                 if (item.Value != null && item.Key != "{OriginalFormat}")
@@ -319,6 +326,13 @@ internal static Models.Trace ConvertToLogDocument(LogRecord logRecord)
 
             int propertiesCount = 0;
 
+            var categoryName = logRecord.CategoryName;
+            if (!string.IsNullOrEmpty(categoryName))
+            {
+                traceDocument.Properties.Add(new KeyValuePairString("CategoryName", categoryName));
+                propertiesCount++;
+            }
+
             foreach (KeyValuePair<string, object?> item in logRecord.Attributes ?? Enumerable.Empty<KeyValuePair<string, object?>>())
             {
                 if (item.Value != null && item.Key != "{OriginalFormat}")

sdk/monitor/Azure.Monitor.OpenTelemetry.AspNetCore/tests/Azure.Monitor.OpenTelemetry.AspNetCore.Tests/LiveMetrics/DocumentTests/DocumentTestBase.cs

@@ -55,17 +55,18 @@ internal void PrintActivity(Activity activity)
             }
         }
 
-        internal void VerifyCustomProperties(DocumentIngress document)
+        internal void VerifyCustomProperties(DocumentIngress document, int reservedPropertyCount = 0)
         {
             Assert.Equal(10, document.Properties.Count);
 
-            for (int i = 1; i <= 10; i++)
+            for (int i = 1; i <= (10 - reservedPropertyCount); i++)
             {
                 Assert.Contains(document.Properties, x => x.Key == $"customKey{i}" && x.Value == $"customValue{i}");
             }
 
-            // LiveMetrics supports a maximum of 10 Properties. #11 should not be included.
-            Assert.DoesNotContain(document.Properties, x => x.Key == $"customKey11" && x.Value == $"customValue11");
+            // LiveMetrics supports a maximum of 10 Properties; reservedPropertyCount is the count of properties taken up by standard properties
+            int firstOmittedPropertyIndex = 11 - reservedPropertyCount;
+            Assert.DoesNotContain(document.Properties, x => x.Key == $"customKey{ firstOmittedPropertyIndex }" && x.Value == $"customValue{ firstOmittedPropertyIndex }");
         }
     }
 }

sdk/monitor/Azure.Monitor.OpenTelemetry.AspNetCore/tests/Azure.Monitor.OpenTelemetry.AspNetCore.Tests/LiveMetrics/DocumentTests/LogTests.cs

@@ -66,7 +66,9 @@ public void VerifyLogRecord(bool formatMessage)
                 Assert.Equal("Hello {customKey1} {customKey2} {customKey3} {customKey4} {customKey5} {customKey6} {customKey7} {customKey8} {customKey9} {customKey10} {customKey11}.", logDocument.Message);
             }
 
-            VerifyCustomProperties(logDocument);
+            Assert.Equal(logCategoryName, logDocument.Properties.First(p => p.Key == "CategoryName").Value);
+
+            VerifyCustomProperties(logDocument, 1);
             Assert.DoesNotContain(logDocument.Properties, x => x.Key == "{OriginalFormat}");
 
             // The following "EXTENSION" properties are used to calculate metrics. These are not serialized.
@@ -123,7 +125,9 @@ public void VerifyLogRecordWithException()
             Assert.Equal(typeof(System.Exception).FullName, exceptionDocument.ExceptionType);
             Assert.Equal("Test exception", exceptionDocument.ExceptionMessage);
 
-            VerifyCustomProperties(exceptionDocument);
+            Assert.Equal(logCategoryName, exceptionDocument.Properties.First(p => p.Key == "CategoryName").Value);
+
+            VerifyCustomProperties(exceptionDocument, 1);
             Assert.DoesNotContain(exceptionDocument.Properties, x => x.Key == "{OriginalFormat}");
 
             // The following "EXTENSION" properties are used to calculate metrics. These are not serialized.

sdk/monitor/Azure.Monitor.OpenTelemetry.Exporter/CHANGELOG.md

@@ -8,6 +8,11 @@
 
 ### Bugs Fixed
 
+* Added the `LogRecord.CategoryName` field to log and exception telemetry.
+  Previously the `CategoryName` field was omitted, which was inconsistent with
+  expected `ILogger` behavior, and with Application Insights classic behavior.
+  ([#44754](https://github.com/Azure/azure-sdk-for-net/pull/44754))
+
 ### Features Added
 
 * Added `LoggerProviderBuilder.AddAzureMonitorLogExporter` registration extension.
@@ -96,7 +101,7 @@
   of the OpenTelemetry LoggerProvider. This fix prevents data duplication in
   message fields and properties.
   ([#39308](https://github.com/Azure/azure-sdk-for-net/pull/39308))
-  
+
 * Fixed an issue related to the processing of scopes that do not conform to a
   key-value pair structure.
   ([#39453](https://github.com/Azure/azure-sdk-for-net/pull/39453))
@@ -105,7 +110,7 @@
      'SomeScopeValue' to the properties using a key that follows the pattern
      'scope->*'. Additionally, 'OriginalFormatScope_*' keys were used to handle
      formatted strings within the scope.
-   * **New Behavior**: 
+   * **New Behavior**:
      * Non-key-value pair scopes are no longer added to the properties,
        resulting in cleaner and more efficient log output.
      * 'OriginalFormatScope_*' keys have been removed.
@@ -189,7 +194,7 @@
   ([#36509](https://github.com/Azure/azure-sdk-for-net/pull/36509))
 * Add `db.name` to custom properties.
   ([#36389](https://github.com/Azure/azure-sdk-for-net/pull/36389))
- 
+
 ### Bugs Fixed
 
 * Fixed an issue which resulted in standard metrics getting exported to backends other than Azure Monitor, when Azure Monitor metric exporter was used with other exporters such as otlp side by side.
@@ -318,7 +323,7 @@
 * Request and Dependency Success criteria will now be decided based on
   `Activity.Status` ([#31024](https://github.com/Azure/azure-sdk-for-net/pull/31024))
 * Changed `AzureMonitorTraceExporter` to internal ([#31067](https://github.com/Azure/azure-sdk-for-net/pull/31067))
-  
+
 ### Bugs Fixed
 
 * Fix shared RoleName/RoleInstance between Trace and Log Exporter ([#26438](https://github.com/Azure/azure-sdk-for-net/pull/26438))

sdk/monitor/Azure.Monitor.OpenTelemetry.Exporter/src/Internals/LogsHelper.cs

@@ -124,6 +124,12 @@ internal static List<TelemetryItem> OtelToAzureMonitorLogs(Batch<LogRecord> batc
 
             logRecord.ForEachScope(s_processScope, properties);
 
+            var categoryName = logRecord.CategoryName;
+            if (!properties.ContainsKey("CategoryName") && !string.IsNullOrEmpty(categoryName))
+            {
+                properties.Add("CategoryName", categoryName.Truncate(SchemaConstants.KVP_MaxValueLength)!);
+            }
+
             if (!properties.ContainsKey("EventId") && logRecord.EventId.Id != 0)
             {
                 properties.Add("EventId", logRecord.EventId.Id.ToString(CultureInfo.InvariantCulture));

sdk/monitor/Azure.Monitor.OpenTelemetry.Exporter/tests/Azure.Monitor.OpenTelemetry.Exporter.Tests/E2ETelemetryItemValidation/LogsTests.cs

@@ -83,7 +83,7 @@ public void VerifyLog(LogLevel logLevel, string expectedSeverityLevel)
                 telemetryItem: telemetryItem!,
                 expectedSeverityLevel: expectedSeverityLevel,
                 expectedMessage: "Hello {name}.",
-                expectedMessageProperties: new Dictionary<string, string> { { "EventId", "1" }, { "name", "World" }},
+                expectedMessageProperties: new Dictionary<string, string> { { "EventId", "1" }, { "name", "World" }, { "CategoryName", logCategoryName } },
                 expectedSpanId: null,
                 expectedTraceId: null);
         }

sdk/monitor/Azure.Monitor.OpenTelemetry.Exporter/tests/Azure.Monitor.OpenTelemetry.Exporter.Tests/LogsHelperTests.cs

@@ -61,7 +61,7 @@ public void MessageIsSetToExceptionMessage(bool parseStateValues)
             Assert.Equal("tomato", name);
             Assert.True(properties.TryGetValue("price", out string price));
             Assert.Equal("2.99", price);
-            Assert.Equal(3, properties.Count);
+            Assert.Equal(4, properties.Count);
         }
 
         [Fact]
@@ -91,7 +91,7 @@ public void MessageIsSetToFormattedMessageWhenIncludeFormattedMessageIsSet()
             Assert.Equal("tomato", name);
             Assert.True(properties.TryGetValue("price", out string price));
             Assert.Equal("2.99", price);
-            Assert.Equal(2, properties.Count);
+            Assert.Equal(3, properties.Count);
         }
 
         [Fact]
@@ -121,7 +121,7 @@ public void MessageIsSetToOriginalFormatWhenIncludeFormattedMessageIsNotSet()
             Assert.Equal("tomato", name);
             Assert.True(properties.TryGetValue("price", out string price));
             Assert.Equal("2.99", price);
-            Assert.Equal(2, properties.Count);
+            Assert.Equal(3, properties.Count);
         }
 
         [Theory]
@@ -152,7 +152,7 @@ public void PropertiesContainFieldsFromStructuredLogs(bool parseStateValues)
             Assert.Equal("tomato", name);
             Assert.True(properties.TryGetValue("price", out string price));
             Assert.Equal("2.99", price);
-            Assert.Equal(2, properties.Count);
+            Assert.Equal(3, properties.Count);
         }
 
         [Fact]
@@ -180,7 +180,65 @@ public void PropertiesContainEventIdAndEventNameIfSetOnLog()
             Assert.Equal("1", eventId);
             Assert.True(properties.TryGetValue("EventName", out string eventName));
             Assert.Equal("TestEvent", eventName);
-            Assert.Equal(2, properties.Count);
+            Assert.Equal(3, properties.Count);
+        }
+
+        [Fact]
+        public void PropertiesContainLoggerCategoryName()
+        {
+            var logRecords = new List<LogRecord>();
+            using var loggerFactory = LoggerFactory.Create(builder =>
+            {
+                builder.AddOpenTelemetry(options =>
+                {
+                    options.AddInMemoryExporter(logRecords);
+                });
+                builder.AddFilter(typeof(LogsHelperTests).FullName, LogLevel.Trace);
+            });
+
+            var categoryName = nameof(LogsHelperTests);
+            var logger = loggerFactory.CreateLogger(categoryName);
+
+            logger.LogInformation("Information goes here");
+
+            var properties = new ChangeTrackingDictionary<string, string>();
+            LogsHelper.GetMessageAndSetProperties(logRecords[0], properties);
+
+            Assert.True(properties.TryGetValue("CategoryName", out string loggedCategoryName));
+            Assert.Equal(categoryName, loggedCategoryName);
+            Assert.Single(properties);
+        }
+
+        [Fact]
+        public void ExceptionPropertiesContainLoggerCategoryName()
+        {
+            var logRecords = new List<LogRecord>();
+            using var loggerFactory = LoggerFactory.Create(builder =>
+            {
+                builder.AddOpenTelemetry(options =>
+                {
+                    options.AddInMemoryExporter(logRecords);
+                });
+                builder.AddFilter(typeof(LogsHelperTests).FullName, LogLevel.Trace);
+            });
+
+            var logger = loggerFactory.CreateLogger<LogsHelperTests>();
+            try
+            {
+                throw new Exception("Test Exception");
+            }
+            catch (Exception ex)
+            {
+                logger.LogError(ex, "Here's an error");
+            }
+
+            var properties = new ChangeTrackingDictionary<string, string>();
+            var message = LogsHelper.GetMessageAndSetProperties(logRecords[0], properties);
+
+            Assert.Equal("Test Exception", message);
+
+            Assert.True(properties.TryGetValue("CategoryName", out string categoryName));
+            Assert.EndsWith(nameof(LogsHelperTests), categoryName);
         }
 
         [Fact]
@@ -210,7 +268,7 @@ public void LogRecordAndAttributesContainEventIdAndEventName()
             Assert.Equal("100", eventId);
             Assert.True(properties.TryGetValue("EventName", out string eventName));
             Assert.Equal("TestAttributeEventName", eventName);
-            Assert.Equal(2, properties.Count);
+            Assert.Equal(3, properties.Count);
         }
 
         [Fact]
@@ -348,13 +406,13 @@ public void VerifyHandlingOfVariousScopeDataTypes(object scopeValue)
 
             if (scopeValue != null)
             {
-                Assert.Single(properties); // Assert that there is exactly one property
+                Assert.Equal(2, properties.Count); // Scope property + CategoryName
                 Assert.True(properties.TryGetValue(expectedScopeKey, out string actualScopeValue));
                 Assert.Equal(scopeValue.ToString(), actualScopeValue);
             }
             else
             {
-                Assert.Empty(properties); // Assert that properties are empty
+                Assert.Single(properties); // Single property expected (CategoryName)
             }
         }
 
@@ -438,7 +496,7 @@ public void DuplicateKeysInLogRecordAttributesAndLogScope()
             var properties = new ChangeTrackingDictionary<string, string>();
             LogsHelper.GetMessageAndSetProperties(logRecords[0], properties);
 
-            Assert.Equal(2, properties.Count);
+            Assert.Equal(3, properties.Count);
             Assert.True(properties.TryGetValue(expectedScopeKey, out string actualScopeValue));
             Assert.Equal(expectedScopeValue, actualScopeValue);
             Assert.True(properties.TryGetValue("attributeKey", out string actualAttributeValue));

sdk/monitor/Azure.Monitor.OpenTelemetry.Exporter/tests/Azure.Monitor.OpenTelemetry.Exporter.Tests/MessageDataTests.cs

@@ -41,7 +41,7 @@ public void ValidateMessageData(LogLevel logLevel)
 
             Assert.Equal("Log Message", messageData.Message);
             Assert.Equal(LogsHelper.GetSeverityLevel(logLevel), messageData.SeverityLevel);
-            Assert.Empty(messageData.Properties);
+            Assert.Single(messageData.Properties); // CategoryName property expected
             Assert.Empty(messageData.Measurements);
         }
     }