Microsoft.Extensions.Logging 9.0.0

About

Microsoft.Extensions.Logging is combined with a core logging abstraction under Microsoft.Extensions.Logging.Abstractions. This abstraction is available in our basic built-in implementations like console, event log, and debug (Debug.WriteLine) logging.

Key Features

  • Provide concrete implementations of ILoggerFactory
  • Provide extension methods for service collections, logger builder, and activity tracking
  • Provide logging filtering extension methods for logger builder

How to Use

Prior to .NET 6, we only had two forms possible for doing logging, using Microsoft.Extensions.Logging:

public class LoggingSample1
{
    private ILogger _logger;

    public LoggingSample1(ILogger logger)
    {
        _logger = logger;
    }

    public void LogMethod(string name)
    {
        _logger.LogInformation("Hello {name}", name);
    }
}

Here are some problems with the LoggingSample1 sample using LogInformation, LogWarning, etc.:

  1. We can provide event ID through these APIs, but they are not required today. Which leads to bad usages in real systems that want to react or detect specific event issues being logged.
  2. Parameters passed are processed before LogLevel checks; this leads to unnecessary code paths getting triggered even when logging is disabled for a log level.
  3. It requires parsing of message string on every use to find templates to substitute.

Because of these problems, the more efficient runtime approach recommended as best practices is to use LoggerMessage.Define APIs instead, illustrated below with LoggingSample2:

public class LoggingSample2
{
    private ILogger _logger;

    public LoggingSample2(ILogger logger)
    {
        _logger = logger;
    }

    public void LogMethod(string name)
    {
        Log.LogName(_logger, name);
    }

    private static class Log
    {
        private static readonly Action<ILogger, string, Exception> _logName = LoggerMessage.Define<string>(LogLevel.Information, 0, @"Hello {name}");

        public static void LogName(ILogger logger, string name)
        {
            _logName(logger, name, null!);
        }
    }
}

To reach a balance between performance and usability we added the compile-time logging source generator feature in .NET 6, to learn more about it and learn how to use a source generator to create log messages check out this documentation.


public partial class InstanceLoggingExample
{
    private readonly ILogger _logger;

    public InstanceLoggingExample(ILogger logger)
    {
        _logger = logger;
    }

    [LoggerMessage(
        EventId = 0,
        Level = LogLevel.Critical,
        Message = "Could not open socket to `{hostName}`")]
    public partial void CouldNotOpenSocket(string hostName);
}

Baggage and Tags for ActivityTrackingOptions

.NET 5.0 exposed a new feature that allows configuring the logger builder with the ActivityTrackingOption to add the tracing context Span Id, Trace Id, Parent Id, Trace state, and Trace flags to the logging scope. The tracing context usually carried in Activity.Current.

.NET 6.0 Preview 1 extended this feature to include more tracing context properties which are the Baggage and the Tags:

  var loggerFactory = LoggerFactory.Create(logging =>
  {
      logging.Configure(options =>
      {
          options.ActivityTrackingOptions = ActivityTrackingOptions.Tags | ActivityTrackingOptions.Baggage;
      }).AddSimpleConsole(options =>
      {
          options.IncludeScopes = true;
      });
  });

Main Types

The main types provided by this library are:

  • LoggingServiceCollectionExtensions
  • LoggerFactory
  • LoggerFactoryOptions
  • LoggingBuilderExtensions
  • ActivityTrackingOptions
  • FilterLoggingBuilderExtensions

Additional Documentation

Microsoft.Extensions.Logging.Abstractions Microsoft.Extensions.Logging.Console Microsoft.Extensions.Logging.Debug Microsoft.Extensions.Logging.EventSource Microsoft.Extensions.Logging.EventLog Microsoft.Extensions.Logging.TraceSource

Feedback & Contributing

Microsoft.Extensions.Logging is released as open source under the MIT license. Bug reports and contributions are welcome at the GitHub repository.

Showing the top 20 packages that depend on Microsoft.Extensions.Logging.

Packages Downloads
Microsoft.EntityFrameworkCore.Relational
Shared Entity Framework Core components for relational database providers.
 19
Microsoft.Extensions.Logging.Debug
Debug output logger provider implementation for Microsoft.Extensions.Logging. This logger logs messages to a debugger monitor by writing messages with System.Diagnostics.Debug.WriteLine().
 18
Microsoft.Identity.Web
This package enables ASP.NET Core web apps and web APIs to use the Microsoft identity platform (formerly Azure AD v2.0). This package is specifically used for web applications, which sign-in users, and protected web APIs, which optionally call downstream web APIs.
 17
Microsoft.Extensions.Http
The HttpClient factory is a pattern for configuring and retrieving named HttpClients in a composable way. The HttpClient factory provides extensibility to plug in DelegatingHandlers that address cross-cutting concerns such as service location, load balancing, and reliability. The default HttpClient factory provides built-in diagnostics and logging and manages the lifetimes of connections in a performant way. Commonly Used Types: System.Net.Http.IHttpClientFactory
 17
Microsoft.Extensions.Logging.EventLog
Windows Event Log logger provider implementation for Microsoft.Extensions.Logging.
 16
MartinCostello.Logging.XUnit
Extensions for Microsoft.Extensions.Logging for xunit.
 16
Finbuckle.MultiTenant
Main library package for Finbuckle.MultiTenant.
 16
Microsoft.EntityFrameworkCore.SqlServer
Microsoft SQL Server database provider for Entity Framework Core.
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OpenIddict.Validation.DataProtection
ASP.NET Core Data Protection integration package for the OpenIddict validation services.
 16
Microsoft.Extensions.Logging.EventLog
Windows Event Log logger provider implementation for Microsoft.Extensions.Logging. When using NuGet 3.x this package requires at least version 3.4.
 16
Microsoft.Extensions.Logging.Debug
Debug output logger provider implementation for Microsoft.Extensions.Logging. This logger logs messages to a debugger monitor by writing messages with System.Diagnostics.Debug.WriteLine().
 16
Microsoft.Extensions.Logging.Debug
Debug output logger provider implementation for Microsoft.Extensions.Logging. This logger logs messages to a debugger monitor by writing messages with System.Diagnostics.Debug.WriteLine(). This package was built from the source code at https://github.com/aspnet/Extensions/tree/9bc79b2f25a3724376d7af19617c33749a30ea3a
 16
Microsoft.CodeAnalysis.Workspaces.MSBuild
.NET Compiler Platform ("Roslyn") support for analyzing MSBuild projects and solutions. This should be used with at least one of the following packages to add the appropriate language support: - Microsoft.CodeAnalysis.CSharp.Workspaces - Microsoft.CodeAnalysis.VisualBasic.Workspaces More details at https://aka.ms/roslyn-packages This package was built from the source at https://github.com/dotnet/roslyn/commit/bde21ee2b98b775b010d01a93f81ef587fe80962.
 16
OpenIddict.Core
OpenIddict's core components, used to manage the applications, authorizations, scopes and tokens stored in the database.
 16
OpenIddict.Validation
OpenIddict token validation services. Note: this package only contains the generic/host-agnostic validation components. To use the validation feature on ASP.NET Core or OWIN/Katana, reference the OpenIddict.Validation.AspNetCore or OpenIddict.Validation.Owin package.
 16

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Version Downloads Last updated
9.0.0 14 12/01/2024
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2.0.0 12 06/15/2023