Added explicit setting of the SDK version to ILogger trace calls. (mi…

…crosoft#322)

* Added explicit setting of the SDK version to ILogger trace calls.
* Switched to explicit types for readability.
* Added unit test for AI ILogger setting SDK version on telemetry context.

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

@@ -2,7 +2,9 @@
 {
     using System;
     using System.Collections.Generic;
+    using Microsoft.ApplicationInsights;
     using Microsoft.ApplicationInsights.DataContracts;
+    using Microsoft.ApplicationInsights.Extensibility.Implementation;
     using Microsoft.Extensions.Logging;
 
     /// <summary>
@@ -13,6 +15,7 @@ internal class ApplicationInsightsLogger : ILogger
         private readonly string categoryName;
         private readonly TelemetryClient telemetryClient;
         private readonly Func<string, LogLevel, bool> filter;
+        private readonly string sdkVersion;
 
         /// <summary>
         /// Creates a new instance of <see cref="ApplicationInsightsLogger"/>
@@ -22,6 +25,7 @@ public ApplicationInsightsLogger(string name, TelemetryClient telemetryClient, F
             this.categoryName = name;
             this.telemetryClient = telemetryClient;
             this.filter = filter;
+            this.sdkVersion = SdkVersionUtils.VersionPrefix + SdkVersionUtils.GetAssemblyVersion();
         }
 
         /// <inheritdoc />
@@ -41,19 +45,21 @@ public void Log<TState>(LogLevel logLevel, EventId eventId, TState state, Except
         {
             if (this.IsEnabled(logLevel))
             {
-                var dict = new Dictionary<string, string>();
+                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();
-                var stateDictionary = state as IReadOnlyList<KeyValuePair<string, object>>;
+                IReadOnlyList<KeyValuePair<string, object>> stateDictionary = state as IReadOnlyList<KeyValuePair<string, object>>;
                 if (stateDictionary != null)
                 {
-                    foreach (var item in stateDictionary)
+                    foreach (KeyValuePair<string, object> item in stateDictionary)
                     {
                         dict[item.Key] = Convert.ToString(item.Value);
                     }
                 }
 
-                this.telemetryClient.TrackTrace(formatter(state, exception), this.GetSeverityLevel(logLevel), dict);
+                traceTelemetry.Context.GetInternalContext().SdkVersion = this.sdkVersion;
+                this.telemetryClient.TrackTrace(traceTelemetry);
             }
         }
 

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

@@ -0,0 +1,31 @@
+using Microsoft.ApplicationInsights.AspNetCore.Logging;
+using Microsoft.ApplicationInsights.AspNetCore.Tests.Helpers;
+using Microsoft.ApplicationInsights.Extensibility.Implementation;
+using Microsoft.Extensions.Logging;
+using Xunit;
+
+namespace Microsoft.ApplicationInsights.AspNetCore.Tests.Logging
+{
+    /// <summary>
+    /// Tests for the Application Insights ILogger implementation.
+    /// </summary>
+    public class ApplicationInsightsLoggerTests
+    {
+        /// <summary>
+        /// Tests that the SDK version is correctly set on the telemetry context when messages are logged to AI.
+        /// </summary>
+        [Fact]
+        public void TestLoggerSetsSdkVersionOnLoggedTelemetry()
+        {
+            bool isCorrectVersion = false;
+            TelemetryClient client = CommonMocks.MockTelemetryClient((t) =>
+            {
+                isCorrectVersion = t.Context.GetInternalContext().SdkVersion.StartsWith(SdkVersionUtils.VersionPrefix);
+            });
+
+            ILogger logger = new ApplicationInsightsLogger("test", client, (s, l) => { return true; });
+            logger.LogTrace("This is a test.", new object[] { });
+            Assert.True(isCorrectVersion);
+        }
+    }
+}