Ksh.Logger.Abstractions 2024.1.3

Ksh.Logger

package	version	downloads
Ksh.Logger
Ksh.Logger.Abstractions

The world's most flexible and light-weight logger!

Main contents

• Usage
  • LoggerFactory
  • ServiceCollection
• Customization
  • ILogMessagePropagator
  • ILogMessageFormatter
  • LogSeverity
  • Filter and Verbosity

Usage

LoggerFactory

var logger = new StandardLoggerFactory()
    .AddConsoleLogger()
    .AddFileLogger("path.to.log")
    .CreateLogger();

logger.Info("hello world");

ServiceCollection

Please make sure, the package is installed already.

dotnet add package Microsoft.Extensions.DependencyInjection

You can then set up the logger and register the module. The logger can be added to any class you want after that.

var services = new ServiceCollection();

services.AddKshLogger();
services.AddSingleton<ILogger>(
    srv => srv.GetService<ILoggerFactory>()!
        .AddConsoleLogger()
        .AddFileLogger("path.to.log")
        .CreateLogger()
);

// just for demo, you don't need this in production 
var kernel = services.BuildServiceProvider();
var logger = kernel.GetService<ILogger>()!;

logger.Info("hello world");

You can now log in to a file or console. You can get rid of the console and file propagator if you want to.

Customization

This logger, as mentioned, is extremely adaptable. If you're using a logging framework, you can let it handle the stuff like formatting or so. After a while, you can switch to using only one logger.

There's a layer of abstraction that can be used independently or in UnitTests. That abstraction layer will make you future-proof.

ILogMessagePropagator

This Logger's superpowers are propagators. You can notify anything you want. Simply use the ILogMessagePropagator Interface and do whatever you want with the message.

Every log message will utilize this method.

This example shows how to know if your service has stopped working and send an email when it happens.

public class CustomPropagator(IEmailClient emailClient) : ILogMessagePropagator
{
    public void Propagate(LogMessage message)
    {
        if (message.Severity == LogSeverity.Fatal)
        {
            emailClient.SendEmail(message.Message);
        }
    }
}

You can put this propagator directly into the logger or into the factory.

loggerFactory.AddPropagator(new CustomPropagator(emailClient));

ILogMessageFormatter

Let's talk about the formatters. These sneaky guys are extremely helpful by changing the appearance of the message.

I think it is an edge case to use something different from what was implemented. But you can format any message depending on your needs.

All built-in propagators are using the formatter. Custom propagators are not, but I highly recommend using them as well. Just for consistency purposes.

public class MyCustomLogMessageFormatter : ILogMessageFormatter
{
    public string Format(LogMessage message)
        => message.Exception == null
            ? $"{message.Severity} {message.TimeOfDay:s} {message.Message}"
            : $"{message.Severity} {message.TimeOfDay:s} {message.Message}{Environment.NewLine}{message.Exception}";
}

LogSeverity

We have 6 different severities: Trace, Debug, Info, Warn, Error and Fatal.

Of course, you can use these classifications as you like! From my experience, I would like to provide you with a recommendation. Maybe it is helpful. 😃

Filter and Verbosity

Okay, real-talk. Who the heck is reading log files? Really, no one. They're only useful when you're looking into some issues. One full log file and some only for warnings, errors and so on are what I like to have.

var logger = new StandardLoggerFactory()
    // will log debug and above
    .AddConsoleLogger(new() { 
        Verbosity = LogSeverity.Debug
    })
    // by default everything will be logged!
    .AddFileLogger("noisy.log")
    // will log only infos
    .AddFileLogger(new() {
        OutputFile = "info.log",
        Filter = LogSeverity.Info
    })
    // will track only warnings
    .AddFileLogger("warnings.log", filter: LogSeverity.Warn)
    // will tracks errors and fatals
    .AddFileLogger("errors.log", verbosity: LogSeverity.Error)
    // use some custom propagator
    .CreateLogger();