Apache Log4net .NET Core and Application Insights

In the previous post I revisited my sample .NET application that used Apache log4net and Azure Application Insights. This post updates the application to .NET Core V3.1.

I had to remove the ability to set the instrumentation key via the command line as I couldn’t get it to work.

I tried initialising the logger after loading the telemetry configuration, passing the InstrumentationKey in as a parameter of the TelemetryConfiguration constructor etc. and it made no difference.

The only other option that appeared to work was setting the instrumentation key via an Environment Variable called APPINSIGHTS_INSTRUMENTATIONKEY

   class Program
   {
      private static ILog log = log4net.LogManager.GetLogger(System.Reflection.MethodBase.GetCurrentMethod().DeclaringType);

      static void Main(string[] args)
      {
         using (TelemetryConfiguration telemetryConfiguration = TelemetryConfiguration.CreateDefault())
         {
            TelemetryClient telemetryClient = new TelemetryClient(telemetryConfiguration);

            var logRepository = LogManager.GetRepository(Assembly.GetEntryAssembly());
            XmlConfigurator.Configure(logRepository, new FileInfo(Path.Combine(Environment.CurrentDirectory, "log4net.config")));

            log.Debug("This is a Log4Net Debug message");
            log.Info("This is a Log4Net Info message");
            log.Warn("This is a Log4Net Warning message");
            log.Error("This is a Log4Net Error message");
            log.Fatal("This is a Log4Net Fatal message");

            telemetryClient.Flush();
         }

         Console.WriteLine("Press <enter> to exit");
         Console.ReadLine();
      }
   }

I updated the Log4Net setup to use the ManagedColoredConsoleAppender which required a couple of modifications to the Log4Net.config file. (Initially it was failing because I was using the non US spelling of log4net.Appender.ManagedColoredConsoleAppender)

 <appender name="ColoredConsoleAppender" type="log4net.Appender.ManagedColoredConsoleAppender">
      <mapping>
         <level value="ERROR" />
         <foreColor value="White" />
         <backColor value="Red" />
      </mapping>
      <mapping>
         <level value="DEBUG" />
         <backColor value="Green" />
      </mapping>
      <layout type="log4net.Layout.PatternLayout">
         <conversionPattern value="%date [%thread] %-5level %logger [%property{NDC}] - %message%newline" />
      </layout>
   </appender>

I did notice that after a several seconds while waiting for the enter key to be pressed there were a number of exceptions which warrants further investigation.

devMobile.Azure.ApplicationInsightsLog4NetCoreClient.Program: 2020-04-08 17:14:23,455 [1] FATAL devMobile.Azure.ApplicationInsightsLog4NetCoreClient.Program – This is a Log4Net Fatal message
‘ApplicationInsightsLog4NetCoreClient.exe’ (CoreCLR: clrhost): Loaded ‘C:\Program Files\dotnet\shared\Microsoft.NETCore.App\3.1.3\System.Security.Cryptography.Encoding.dll’.
Exception thrown: ‘System.Threading.Tasks.TaskCanceledException’ in System.Private.CoreLib.dll
Exception thrown: ‘System.Threading.Tasks.TaskCanceledException’ in System.Private.CoreLib.dll
Exception thrown: ‘System.Threading.Tasks.TaskCanceledException’ in System.Private.CoreLib.dll
Exception thrown: ‘System.Threading.Tasks.TaskCanceledException’ in System.Private.CoreLib.dll
Exception thrown: ‘System.Threading.Tasks.TaskCanceledException’ in System.Net.Http.dll
Exception thrown: ‘System.Threading.Tasks.TaskCanceledException’ in System.Private.CoreLib.dll
Exception thrown: ‘System.Threading.Tasks.TaskCanceledException’ in System.Private.CoreLib.dll
Exception thrown: ‘System.Threading.Tasks.TaskCanceledException’ in System.Private.CoreLib.dll
Exception thrown: ‘System.Threading.Tasks.TaskCanceledException’ in System.Net.Http.dll
Exception thrown: ‘System.Threading.Tasks.TaskCanceledException’ in System.Private.CoreLib.dll
Exception thrown: ‘System.Threading.Tasks.TaskCanceledException’ in System.Net.Http.dll
Exception thrown: ‘System.Threading.Tasks.TaskCanceledException’ in System.Private.CoreLib.dll
Exception thrown: ‘System.Threading.Tasks.TaskCanceledException’ in System.Private.CoreLib.dll
Exception thrown: ‘System.Threading.Tasks.TaskCanceledException’ in System.Private.CoreLib.dll
The program ‘[13920] ApplicationInsightsLog4NetCoreClient.exe’ has exited with code 0 (0x0).
The program ‘[13920] ApplicationInsightsLog4NetCoreClient.exe: Program Trace’ has exited with code 0 (0x0).

A sample project is available here.

“Don’t forget to flush” .Net Core Application Insights

This post updates a previous post “Don’t forget to flush Application insights Revisited” for .Net Core 3.X and shows the small change required by the deprecation of on of the TelemetryClient constructor overloads.

warning CS0618: ‘TelemetryClient.TelemetryClient()’ is obsolete: ‘We do not recommend using TelemetryConfiguration.Active on .NET Core. See https://github.com/microsoft/ApplicationInsights-dotnet/issues/1152 for more details’

   class Program
   {
      static void Main(string[] args)
      {
#if INSTRUMENTATION_KEY_TELEMETRY_CONFIGURATION
         if (args.Length != 1)
         {
            Console.WriteLine("Usage AzureApplicationInsightsClientConsole <instrumentationKey>");
            return;
         }

         TelemetryConfiguration telemetryConfiguration = new TelemetryConfiguration(args[0]);
         TelemetryClient telemetryClient = new TelemetryClient(telemetryConfiguration);
         telemetryClient.TrackTrace("INSTRUMENTATION_KEY_TELEMETRY_CONFIGURATION", SeverityLevel.Information);
#endif
#if INSTRUMENTATION_KEY_APPLICATION_INSIGHTS_CONFIG
         TelemetryConfiguration telemetryConfiguration = TelemetryConfiguration.CreateDefault();
         TelemetryClient telemetryClient = new TelemetryClient(telemetryConfiguration);
         telemetryClient.TrackTrace("INSTRUMENTATION_KEY_APPLICATION_INSIGHTS_CONFIG", SeverityLevel.Information);
#endif
         telemetryClient.Context.User.Id = Environment.UserName;
         telemetryClient.Context.Device.Id = Environment.MachineName;
         telemetryClient.Context.Operation.Name = "Test harness";

         telemetryClient.TrackTrace("This is a .Net Core AI API Verbose message", SeverityLevel.Verbose);
         telemetryClient.TrackTrace("This is a .Net Core AI API Information message", SeverityLevel.Information);
         telemetryClient.TrackTrace("This is a .Net Core AI API Warning message", SeverityLevel.Warning);
         telemetryClient.TrackTrace("This is a .Net Core AI API Error message", SeverityLevel.Error);
         telemetryClient.TrackTrace("This is a .Net Core AI API Critical message", SeverityLevel.Critical);

         telemetryClient.Flush();

         telemetryConfiguration.Dispose(); // In real-world use a using or similar approach to ensure cleaned up

         Console.WriteLine("Press <enter> to exit");
         Console.ReadLine();
      }
   }

A sample project is available here