Log SDK resolution result

src/Build.UnitTests/BackEnd/SdkResolverService_Tests.cs

@@ -111,7 +111,6 @@ public void AssertResolverThrows()
             e.Sdk.Name.ShouldBe("1sdkName");
         }
 
-
         [Fact]
         // Scenario: MockSdkResolverWithResolvableSdkPattern2 is a specific resolver (i.e. resolver with pattern)
         // and it successfully resolves sdk.
@@ -184,6 +183,21 @@ public void AssertFirstResolverWithPatternCanResolve()
             _logger.BuildMessageEvents.Select(i => i.Message).ShouldNotContain("MockSdkResolver1 running");
         }
 
+        [Fact]
+        public void AssertSdkResolutionMessagesAreLogged()
+        {
+            SdkResolverService.Instance.InitializeForTests(new MockLoaderStrategy());
+            SdkReference sdk = new SdkReference("1sdkName", "referencedVersion", "minimumVersion");
+
+            var result = SdkResolverService.Instance.ResolveSdk(BuildEventContext.InvalidSubmissionId, sdk, _loggingContext, new MockElementLocation("file"), "sln", "projectPath", interactive: false, isRunningInVisualStudio: false, failOnUnresolvedSdk: true);
+
+            // First resolver attempted to resolve, but failed.
+            _logger.BuildMessageEvents.Select(i => i.Message).ShouldContain(ResourceUtilities.FormatResourceStringStripCodeAndKeyword("SDKResolverAttempt", nameof(MockResolverReturnsNull), sdk.ToString(), "null",
+                ResourceUtilities.FormatResourceStringStripCodeAndKeyword("SDKResolverReturnedNull", nameof(MockResolverReturnsNull))));
+            // Second resolver succeeded.
+            _logger.BuildMessageEvents.Select(i => i.Message).ShouldContain(ResourceUtilities.FormatResourceStringStripCodeAndKeyword("SucceededToResolveSDK", sdk.ToString(), nameof(MockSdkResolver1), result.Path, result.Version));
+        }
+
         [Fact]
         public void AssertFirstResolverErrorsSupressedWhenResolved()
         {

src/Build/BackEnd/Components/SdkResolution/SdkResolverService.cs

@@ -312,8 +312,6 @@ private bool TryResolveSdkUsingSpecifiedResolvers(
             // Loop through resolvers which have already been sorted by priority, returning the first result that was successful
             SdkLogger buildEngineLogger = new SdkLogger(loggingContext);
 
-            loggingContext.LogComment(MessageImportance.Low, "SdkResolving", sdk.ToString());
-
             foreach (SdkResolver sdkResolver in resolvers)
             {
                 SdkResolverContext context = new SdkResolverContext(buildEngineLogger, projectPath, solutionPath, ProjectCollection.Version, interactive, isRunningInVisualStudio)
@@ -355,6 +353,8 @@ private bool TryResolveSdkUsingSpecifiedResolvers(
 
                 if (result.Success)
                 {
+                    loggingContext.LogComment(MessageImportance.Low, "SucceededToResolveSDK", sdk.ToString(), sdkResolver.Name, result.Path ?? "null", result.Version ?? "null");
+
                     LogWarnings(loggingContext, sdkReferenceLocation, result.Warnings);
 
                     if (!IsReferenceSameVersion(sdk, result.Version))
@@ -369,6 +369,13 @@ private bool TryResolveSdkUsingSpecifiedResolvers(
                     sdkResult = result;
                     return true;
                 }
+                else if (loggingContext.LoggingService.MinimumRequiredMessageImportance >= MessageImportance.Low)
+                {
+                    string resultWarnings = result.Warnings?.Any() == true ? string.Join(Environment.NewLine, result.Warnings) : "null";
+                    string resultErrors = result.Errors?.Any() == true ? string.Join(Environment.NewLine, result.Errors) : "null";
+
+                    loggingContext.LogComment(MessageImportance.Low, "SDKResolverAttempt", sdkResolver.Name, sdk.ToString(), resultWarnings, resultErrors);
+                }
 
                 results.Add(result);
             }

src/Build/Resources/Strings.resx

@@ -1324,6 +1324,17 @@
     <value>Could not resolve SDK "{0}". Exactly one of the probing messages below indicates why we could not resolve the SDK. Investigate and resolve that message to correctly specify the SDK.
   {1}</value>
   </data>
+  <data name="SucceededToResolveSDK" xml:space="preserve">
+    <value>The SDK "{0}" was successfully resolved by the "{1}" resolver to location "{2}" and version "{3}".</value>
+  </data>
+  <data name="SDKResolverAttempt" xml:space="preserve">
+    <value>The "{0}" resolver attempted to resolve the SDK "{1}".
+Warnings: {2}
+Errors: {3}</value>
+    <comment>
+      LOCALIZATION: Do not localize the word SDK. "{2}" is new line separated warnings or "null". "{3}" is new line separated errors or "null".
+    </comment>
+  </data>
   <data name="CouldNotRunNuGetSdkResolver" xml:space="preserve">
     <value>The NuGet-based SDK resolver failed to run because NuGet assemblies could not be located.  Check your installation of MSBuild or set the environment variable "{0}" to the folder that contains the required NuGet assemblies. {1}</value>
   </data>
@@ -1769,12 +1780,6 @@ Utilization:          {0} Average Utilization: {1:###.0}</value>
       LOCALIZATION:  Do not localize the word SDK.
     </comment>
   </data>
-  <data name="SdkResolving" xml:space="preserve">
-    <value>Resolving SDK '{0}'...</value>
-    <comment>
-      LOCALIZATION:  Do not localize the word SDK.
-    </comment>
-  </data>
   <data name="ProjectGraphDoesNotSupportProjectReferenceWithToolset" xml:space="preserve">
     <value>MSB4250: ProjectGraph does not support ProjectReference items with the ToolsVersion metadata set. Found ProjectReference "{0}" with ToolsVersion in file "{1}"</value>
     <comment>