examples/Tutorials/ConsoleApp/LoggingExample.cs

#region Apache License
//
// Licensed to the Apache Software Foundation (ASF) under one or more 
// contributor license agreements. See the NOTICE file distributed with
// this work for additional information regarding copyright ownership. 
// The ASF licenses this file to you under the Apache License, Version 2.0
// (the "License"); you may not use this file except in compliance with 
// the License. You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//
#endregion

// Configure log4net using the .config file
[assembly: log4net.Config.XmlConfigurator(Watch = true)]
// This will cause log4net to look for a configuration file
// called ConsoleApp.exe.config in the application base
// directory (i.e. the directory containing ConsoleApp.exe)

namespace ConsoleApp;

using System;

/// <summary>
/// Example of how to simply configure and use log4net
/// </summary>
public static class LoggingExample
{
  // Create a logger for use in this class
  private static readonly log4net.ILog _log = log4net.LogManager.GetLogger(typeof(LoggingExample));

  /// <summary>
  /// Application entry point
  /// </summary>
  [System.Diagnostics.CodeAnalysis.SuppressMessage("Globalization", "CA1303:Do not pass literals as localized parameters")]
  public static void Main()
  {
    // Log an info level message
    if (_log.IsInfoEnabled)
    {
      _log.Info("Application [ConsoleApp] Start");
    }

    // Log a debug message. Test if debug is enabled before
    // attempting to log the message. This is not required but
    // can make running without logging faster.
    if (_log.IsDebugEnabled)
    {
      _log.Debug("This is a debug message");
    }

    try
    {
      Bar();
    }
    catch (InvalidOperationException ex)
    {
      // Log an error with an exception
      _log.Error("Exception thrown from method Bar", ex);
    }

    _log.Error("Hey this is an error!");

    // Push a message on to the Nested Diagnostic Context stack
    using (log4net.NDC.Push("NDC_Message"))
    {
      _log.Warn("This should have an NDC message");

      // Set a Mapped Diagnostic Context value  
      log4net.MDC.Set("auth", "auth-none");
      _log.Warn("This should have an MDC message for the key 'auth'");

    } // The NDC message is popped off the stack at the end of the using {} block

    _log.Warn("See the NDC has been popped of! The MDC 'auth' key is still with us.");

    // Log an info level message
    if (_log.IsInfoEnabled)
    {
      _log.Info("Application [ConsoleApp] End");
    }

    Console.Write("Press Enter to exit...");
    Console.ReadLine();
  }

  // Helper methods to demonstrate location information and nested exceptions

  private static void Bar() => Goo();

  private static void Foo() => throw new InvalidOperationException("This is an Exception");

  private static void Goo()
  {
    try
    {
      Foo();
    }
    catch (Exception ex)
    {
      throw new ArithmeticException("Failed in Goo. Calling Foo. Inner Exception provided", ex);
    }
  }
}