Is it a good practice to have logger as a singleton?

c# .net logging dependency-injection singleton
Giedrius picture Giedrius · Dec 12, 2011 · Viewed 33.9k times · Source

I had a habit to pass logger to constructor, like:

public class OrderService : IOrderService {
     public OrderService(ILogger logger) {
     }
}

But that is quite annoying, so I've used it a property this for some time:

private ILogger logger = NullLogger.Instance;
public ILogger Logger
{
    get { return logger; }
    set { logger = value; }
}

This is getting annoying too - it is not dry, I need to repeat this in every class. I could use base class, but then again - I'm using Form class, so would need FormBase, etc. So I think, what would be downside of having singleton with ILogger exposed, so veryone would know where to get logger:

    Infrastructure.Logger.Info("blabla");

UPDATE: As Merlyn correctly noticed, I've should mention, that in first and second examples I am using DI.

Answer

Daniel Rose picture Daniel Rose · Dec 12, 2011

I put a logger instance in my dependency injection container, which then injects the logger into the classes which need one.

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