C# Interview Question #166

What is logging in ASP.NET Core?

ASP.NET Core, DI & Middleware Senior Advanced

Quick Interview Answer

ASP.NET Core provides the ILogger<T> abstraction for structured application logging.

Detailed Explanation

ASP.NET Core provides the ILogger<T> abstraction for structured application logging.

Structured logging uses message templates and named values instead of constructing large strings manually. This allows log systems to query properties such as ProductId, UserId, or OrderId.

Applications should choose appropriate log levels, avoid logging secrets or sensitive data, and include enough context to diagnose failures without producing excessive noise.

Code Example

public class ProductService
{
    private readonly ILogger<ProductService> _logger;

    public ProductService(ILogger<ProductService> logger)
    {
        _logger = logger;
    }

    public void Process(int productId)
    {
        _logger.LogInformation(
            "Processing product {ProductId}",
            productId);
    }
}