Implement logging with Serilog

Logging can be critical to the success of an application which range from an enterprise application to an application and developer wrote to get paid for.

Without proper logging, imagine attempting to assist a customer or business user were going to their location is impossible and/or using Microsoft Teams or similar application does not provide sufficient information to diagnose the problem.

By adding logging capabilities to an application which than can be sent to the developer can save time figuring out a problem.

Scope of information

There are many options and libraries for SeriLog, the information provide should be considered the basics to intermidate level for logging.

Log levels

Before you begin logging understand .NET has six main logging levels:

Level	Description
Critical	Identifies failures possibly leaving the app unable to function correctly. Exceptions such as out-of-memory and disk running out of space fall in this category.
Error	Identifies errors and exceptions disrupting an operation, such as a database error preventing a record from being saved. Despite encountering errors for an operation, the application can continue functioning normally for other operations.
Warning	A warning might not crash the application, but it’s an issue potentially leading to more critical errors. A warning is simply a level for alerting the administrator of a possible problem.
Information	Provides details about what’s happening behind the scenes in the application. Log messages can provide context when you need to understand the steps leading to an error.
Debug	Tracks detailed information useful during development.
Trace	Also tracks detailed information and may include sensitive information such as passwords. It has minimal use and isn’t used at all by framework libraries.

Obsolete

As SeriLog matures there will be some libraries that will become obsolete, they may still work and with that advise to not use them as these libraries may break functionality down the road.

Project	Description
BasicLogging1	This project shows logging to the console which can be useful for learning and/or for debugging as one learns how to code.
SqlServerSink	This project shows how to log to a SQL-Server database using NuGet package Serilog.Sinks.MSSqlServer. Karen took this from the NuGet package repository site and made major changes which include using net7
HidePathInExceptions	This project showcases logging to a file. Note the file Serilog.json is used to configure SeriLog. There are two additional json files, one for disabling logging so a developer need not change code, only one setting.
MultipleSubmitButtons2	Example to show how to create custom SeriLog color themes for the console in a Razor page project
SeriLogLibrary	Class project, currently contains methods to change colors for writing to the console.
WriteSeparateFromEfCore	Demonstrates SeriLog writing to a log and EF Core to a different log
WriteToNotePadApp	Demonstrates using a third party sink to write logs to notepad
ConditionalLogging	Example to enable/disable logging using appsettings.json and a class for configuring logging
ConditionalLoggingToggle	Helper utility for ConditionalLogging with full documentation
LogForContext	Shows how to log to a file using source contexts

Which NuGet packages do I need?

In Solution Explorer, double click on a project which will open the project file, copy out what is needed,

Say these are what are needed

<PackageReference Include="Microsoft.VisualStudio.Web.CodeGeneration.Design" Version="7.0.3" />
<PackageReference Include="Serilog.AspNetCore" Version="6.1.0" />
<PackageReference Include="Serilog.Extensions.Logging.File" Version="3.0.0" />
<PackageReference Include="Serilog.Sinks.Console" Version="4.1.0" />
<PackageReference Include="Serilog.Sinks.File" Version="5.0.0" />

Now open your project file and add

<ItemGroup>

</ItemGroup>

Now paste the package references into the above group and save the project file.

<ItemGroup>
   <PackageReference Include="Microsoft.VisualStudio.Web.CodeGeneration.Design" Version="7.0.3" />
   <PackageReference Include="Serilog.AspNetCore" Version="6.1.0" />
   <PackageReference Include="Serilog.Extensions.Logging.File" Version="3.0.0" />
   <PackageReference Include="Serilog.Sinks.Console" Version="4.1.0" />
   <PackageReference Include="Serilog.Sinks.File" Version="5.0.0" />
</ItemGroup>

Lastly, open Manage NuGet packages for your project, the references are there, see if there are any updates and if so update them.

Setup

In short, install NuGet packages Serilog for basics. In these code samples will will use for logging to files.

• Serilog
• Serilog.Settings.AppSettings
• Serilog.Settings.Configuration
• Serilog.Sinks.File

Once installed these will be in the project file (you can take a fast track, open your project file, copy-n-paste then save).

<ItemGroup>
    <PackageReference Include="Microsoft.Extensions.Configuration.Json" Version="6.0.0" />
    <PackageReference Include="Serilog" Version="2.11.0" />
    <PackageReference Include="Serilog.Settings.AppSettings" Version="2.2.2" />
    <PackageReference Include="Serilog.Settings.Configuration" Version="3.3.0" />
    <PackageReference Include="Serilog.Sinks.File" Version="5.0.0" />
</ItemGroup>

Basic use

Example for writing to the console see project BasicLogging1

Code in a console app

Add the following to a method.

using var log = new LoggerConfiguration()
    .WriteTo.Console()
    .CreateLogger();

Write information to the log

using System.Runtime.CompilerServices;
using ConsoleHelperLibrary.Classes;
using Serilog;
using Spectre.Console;

namespace BasicLogging1;

internal class Program
{
    static void Main(string[] args)
    {
        AnsiConsole.MarkupLine("[cyan]Creating log[/]");
        Console.WriteLine();

        using var log = new LoggerConfiguration()
            .WriteTo.Console()
            .CreateLogger();

        AnsiConsole.MarkupLine("[cyan]Simple logging[/]");
        log.Information("Hello, Serilog!");
        Console.WriteLine();
        log.Error(new Exception("Bogus"), "Your message goes here");
        Console.WriteLine();
        log.Warning(new Exception("Bogus"),"Your warning");
        Console.WriteLine();
        Console.ReadLine();
    }
}

Configuration Basics

Serilog uses a simple C# API to configure logging. When external configuration is desirable it can be mixed in (sparingly) using the Serilog.Settings.AppSettings package or Serilog.Settings.Configuration package.

Although in the following example which writes to a file we will keep things simple for the sack of learning.

Writing Log Events

Log events are written to sinks using the Log static class, or the methods on an ILogger. These examples will use Log for syntactic brevity, but the same methods shown below are available also on the interface.

Once you have learned the basics dive into this page for indepth information on what is possible with logging past the basics.

Writing to a database

https://github.com/serilog-mssql/serilog-sinks-mssqlserver

Provided Sinks

Serilog provides sinks for writing log events to storage in various formats. Many of the sinks listed below are developed and supported by the wider Serilog community; please direct questions and issues to the relevant repository.

List of available sinks

See also

• SeriLog home page
• Serilog Best Practices ✔️
• Seq log viewer
• Debugging and Diagnostics
• Formatting Output
  • Customized JSON formatting with Serilog

Closing thoughts

There are other logging libraries out there, this one may or may not be right for you. The best way to decide is look over the code samples presented along with SeriLog documentation.

What has been presented are the very basics except for a few items like how to disable logging via the json configuration file which is a plus as otherwise the developer must figure out how to disable e.g. perhaps with conditional statements which simply clutters up the code of an application.