Use ExceptionTelemetry for tracking exceptions

src/Microsoft.ApplicationInsights.AspNetCore/Logging/Implementation/ApplicationInsightsLogger.cs

@@ -3,6 +3,7 @@
     using System;
     using System.Collections.Generic;
     using Microsoft.ApplicationInsights;
+    using Microsoft.ApplicationInsights.Channel;
     using Microsoft.ApplicationInsights.DataContracts;
     using Microsoft.ApplicationInsights.Extensibility.Implementation;
     using Microsoft.Extensions.Logging;
@@ -45,22 +46,38 @@ public void Log<TState>(LogLevel logLevel, EventId eventId, TState state, Except
         {
             if (this.IsEnabled(logLevel))
             {
-                TraceTelemetry traceTelemetry = new TraceTelemetry(formatter(state, exception), this.GetSeverityLevel(logLevel));
-                IDictionary<string, string> dict = traceTelemetry.Context.Properties;
-                dict["CategoryName"] = this.categoryName;
-                dict["Exception"] = exception?.ToString();
-                IReadOnlyList<KeyValuePair<string, object>> stateDictionary = state as IReadOnlyList<KeyValuePair<string, object>>;
-                if (stateDictionary != null)
+                var stateDictionary = state as IReadOnlyList<KeyValuePair<string, object>>;
+                if (exception == null)
                 {
-                    foreach (KeyValuePair<string, object> item in stateDictionary)
-                    {
-                        dict[item.Key] = Convert.ToString(item.Value);
-                    }
+                    var traceTelemetry = new TraceTelemetry(formatter(state, exception), this.GetSeverityLevel(logLevel));
+                    PopulateTelemetry(traceTelemetry, stateDictionary);
+                    this.telemetryClient.TrackTrace(traceTelemetry);
                 }
+                else
+                {
+                    var exceptionTelemetry = new ExceptionTelemetry(exception);
+                    exceptionTelemetry.Message = formatter(state, exception);
+                    exceptionTelemetry.SeverityLevel = this.GetSeverityLevel(logLevel);
+                    exceptionTelemetry.Context.Properties["Exception"] = exception.ToString();
+                    PopulateTelemetry(exceptionTelemetry, stateDictionary);
+                    this.telemetryClient.TrackException(exceptionTelemetry);
+                }
+            }
+        }
 
-                traceTelemetry.Context.GetInternalContext().SdkVersion = this.sdkVersion;
-                this.telemetryClient.TrackTrace(traceTelemetry);
+        private void PopulateTelemetry(ITelemetry telemetry, IReadOnlyList<KeyValuePair<string, object>> stateDictionary)
+        {
+            IDictionary<string, string> dict = telemetry.Context.Properties;
+            dict["CategoryName"] = this.categoryName;
+            if (stateDictionary != null)
+            {
+                foreach (KeyValuePair<string, object> item in stateDictionary)
+                {
+                    dict[item.Key] = Convert.ToString(item.Value);
+                }
             }
+
+            telemetry.Context.GetInternalContext().SdkVersion = this.sdkVersion;
         }
 
         private SeverityLevel GetSeverityLevel(LogLevel logLevel)

test/Microsoft.ApplicationInsights.AspNetCore.Tests/Logging/ApplicationInsightsLoggerTests.cs

@@ -1,5 +1,7 @@
-using Microsoft.ApplicationInsights.AspNetCore.Logging;
+using System;
+using Microsoft.ApplicationInsights.AspNetCore.Logging;
 using Microsoft.ApplicationInsights.AspNetCore.Tests.Helpers;
+using Microsoft.ApplicationInsights.DataContracts;
 using Microsoft.ApplicationInsights.Extensibility.Implementation;
 using Microsoft.Extensions.Logging;
 using Xunit;
@@ -28,6 +30,26 @@ public void TestLoggerSetsSdkVersionOnLoggedTelemetry()
             Assert.True(isCorrectVersion);
         }
 
+        /// <summary>
+        /// Tests that logging an exception results in tracking an <see cref="ExceptionTelemetry"/> instance.
+        /// </summary>
+        [Fact]
+        public void TestLoggerCreatesExceptionTelemetryOnLoggedError()
+        {
+            TelemetryClient client = CommonMocks.MockTelemetryClient((t) =>
+            {
+                Assert.IsType<ExceptionTelemetry>(t);
+                var exceptionTelemetry = (ExceptionTelemetry)t;
+                Assert.Equal("Error: This is an error", exceptionTelemetry.Message);
+                Assert.Equal("System.Exception: This is an error", exceptionTelemetry.Properties["Exception"]);
+                Assert.Equal(SeverityLevel.Error, exceptionTelemetry.SeverityLevel);
+            });
+
+            ILogger logger = new ApplicationInsightsLogger("test", client, (s, l) => { return true; });
+            var exception = new Exception("This is an error");
+            logger.LogError(0, exception, "Error: " + exception.Message);
+        }
+
         /// <summary>
         /// Tests that an incorrectly constructed or uninitialized Application Insights ILogger does not throw exceptions.
         /// </summary>