## About
<!-- A description of the package and where one can find more documentation -->
`Microsoft.Extensions.Logging.Abstractions` provides abstractions of logging. Interfaces defined in this package are implemented by classes in [Microsoft.Extensions.Logging](https://www.nuget.org/packages/Microsoft.Extensions.Logging/) and other logging packages.
This package includes a logging source generator that produces highly efficient and optimized code for logging message methods.
## Key Features
<!-- The key features of this package -->
* Define main logging abstraction interfaces like ILogger, ILoggerFactory, ILoggerProvider, etc.
## How to Use
<!-- A compelling example on how to use this package with code, as well as any specific guidelines for when to use the package -->
#### Custom logger provider implementation example
```C#
using Microsoft.Extensions.Logging;
public sealed class ColorConsoleLogger : ILogger
{
private readonly string _name;
private readonly Func<ColorConsoleLoggerConfiguration> _getCurrentConfig;
public ColorConsoleLogger(
string name,
Func<ColorConsoleLoggerConfiguration> getCurrentConfig) =>
(_name, _getCurrentConfig) = (name, getCurrentConfig);
public IDisposable? BeginScope<TState>(TState state) where TState : notnull => default!;
public bool IsEnabled(LogLevel logLevel) =>
_getCurrentConfig().LogLevelToColorMap.ContainsKey(logLevel);
public void Log<TState>(
LogLevel logLevel,
EventId eventId,
TState state,
Exception? exception,
Func<TState, Exception?, string> formatter)
{
if (!IsEnabled(logLevel))
{
return;
}
ColorConsoleLoggerConfiguration config = _getCurrentConfig();
if (config.EventId == 0 || config.EventId == eventId.Id)
{
ConsoleColor originalColor = Console.ForegroundColor;
Console.ForegroundColor = config.LogLevelToColorMap[logLevel];
Console.WriteLine($"[{eventId.Id,2}: {logLevel,-12}]");
Console.ForegroundColor = originalColor;
Console.Write($" {_name} - ");
Console.ForegroundColor = config.LogLevelToColorMap[logLevel];
Console.Write($"{formatter(state, exception)}");
Console.ForegroundColor = originalColor;
Console.WriteLine();
}
}
}
```
#### Create logs
```csharp
// Worker class that uses logger implementation of teh interface ILogger<T>
public sealed class Worker : BackgroundService
{
private readonly ILogger<Worker> _logger;
public Worker(ILogger<Worker> logger) =>
_logger = logger;
protected override async Task ExecuteAsync(CancellationToken stoppingToken)
{
while (!stoppingToken.IsCancellationRequested)
{
_logger.LogInformation("Worker running at: {time}", DateTimeOffset.UtcNow);
await Task.Delay(1_000, stoppingToken);
}
}
}
```
#### Use source generator
```csharp
public static partial class Log
{
[LoggerMessage(
EventId = 0,
Level = LogLevel.Critical,
Message = "Could not open socket to `{hostName}`")]
public static partial void CouldNotOpenSocket(this ILogger logger, string hostName);
}
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);
}
```
## Main Types
<!-- The main types provided in this library -->
The main types provided by this library are:
* `Microsoft.Extensions.Logging.ILogger`
* `Microsoft.Extensions.Logging.ILoggerProvider`
* `Microsoft.Extensions.Logging.ILoggerFactory`
* `Microsoft.Extensions.Logging.ILogger<TCategoryName>`
* `Microsoft.Extensions.Logging.LogLevel`
* `Microsoft.Extensions.Logging.Logger<T>`
* `Microsoft.Extensions.Logging.LoggerMessage`
* `Microsoft.Extensions.Logging.Abstractions.NullLogger`
## Additional Documentation
<!-- Links to further documentation. Remove conceptual documentation if not available for the library. -->
* [Conceptual documentation](https://learn.microsoft.com/dotnet/core/extensions/logging)
* [API documentation](https://learn.microsoft.com/dotnet/api/microsoft.extensions.logging)
## Related Packages
<!-- The related packages associated with this package -->
[Microsoft.Extensions.Logging](https://www.nuget.org/packages/Microsoft.Extensions.Logging)
[Microsoft.Extensions.Logging.Console](https://www.nuget.org/packages/Microsoft.Extensions.Logging.Console)
[Microsoft.Extensions.Logging.Debug](https://www.nuget.org/packages/Microsoft.Extensions.Logging.Debug)
[Microsoft.Extensions.Logging.EventSource](https://www.nuget.org/packages/Microsoft.Extensions.Logging.EventSource)
[Microsoft.Extensions.Logging.EventLog](https://www.nuget.org/packages/Microsoft.Extensions.Logging.EventLog)
[Microsoft.Extensions.Logging.TraceSource](https://www.nuget.org/packages/Microsoft.Extensions.Logging.TraceSource)
## Feedback & Contributing
<!-- How to provide feedback on this package and contribute to it -->
Microsoft.Extensions.Logging.Abstractions is released as open source under the [MIT license](https://licenses.nuget.org/MIT). Bug reports and contributions are welcome at [the GitHub repository](https://github.com/dotnet/runtime).