Is it better to use Serilog with or without Microsoft.Extensions.Logging?

Question

I'm building an API using .NET 6 and plan to use Serilog as logger. According to https://onloupe.com/blog/serilog-vs-mel/ there are two possibilities:

• Use Serilog exclusively
• Use Microsoft.Extensions.Logging as logging API + Serilog as logging framework

On the one hand, using Serilog exclusively has the drawback that everything in my codebase would take a dependency on Serilog, so using it in combination with Microsoft.Extensions.Logging should provide more flexibility.

On the other hand, on https://github.com/serilog/serilog-extensions-logging they clearly recommend to use https://github.com/serilog/serilog-aspnetcore for .NET Core projects:

ASP.NET Core applications should prefer Serilog.AspNetCore and UseSerilog() instead.

Does anybody know the reason for this recommendation which looks contradictory to me in terms of flexibility?

Answer 1

I think the recommendation:

ASP.NET Core applications should prefer Serilog.AspNetCore and UseSerilog() instead.

is not really talking about which ILogger abstraction to use in your application code -- Microsoft or Serilog. I think it's more about choosing between the low-level Serilog.Extensions.Logging package or the higher level Serilog.AspNetCore package (which depends on the former).

The Serilog.AspNetCore package brings in some useful features like a request logging and integration directly with the generic host. Things you're likely to want in an ASP.NET Core application. The Serilog.Extensions.Logging package is more suited for scenarios where you're not using a generic host, e.g. a console application.

Regarding whether to prefer using Microsoft's ILogger abstraction or Serilog's: It depends. In library code that you expect to share across diverse projects (or publicly), I'd probably stick to Microsoft's abstractions for maximum compatibility and to not force an unwelcome dependency on consumers. Similarly, if you think there's any chance you'll someday want to swap out logging frameworks, you'll probably have an easier time if you stick to using the Microsoft APIs.

On the other hand, you might prefer the ergonomics of Serilog's API over Microsoft's. For example, maybe you like the convenience of a static Log and LogContext APIs without all the ceremony of injected logger. And the IDiagnosticContext abstraction (along with the above mentioned ASP.NET Core request logger) is a really powerful logging pattern. Those would be good reasons to go "all-in" with Serilog.