Seriog filter that excludes by SourceContext's base type

Question

I'm using Serilog with a variety of sinks. One can prevent emitting the Dog class' log events to some sink:

.Filter.ByExcluding(Matching.FromSource<Dog>())

But I can't filter by base type, e.g.:

.Filter.ByExcluding(Matching.FromAssignableSource<Animal>())

I added a feature request for such functionality.

For the time being, is there a workaround?

Answer 1

I found a workaround. It uses reflection but that's acceptable as a one-time operation during app start.

public abstract class Animal { }

public class Dog : Animal { }
public class Cat : Animal { }

// one-time reflection
var names =
  Assembly.GetExecutingAssembly()
  .GetTypes()
  .Where(x => x.IsAssignableTo(typeof(Animal)))
  .Where(x => x != typeof(Animal))
  .Select(x => x.FullName!);
Func<LogEvent, bool> matcher = logEvent => 
  names.Select(name => Matching.FromSource(name))
  .Any(predicate => predicate(logEvent));

// config
.WriteTo.Logger(x => x
  .Filter.ByExcluding(matcher)      // or .Filter.ByIncludingOnly(matcher)
  .WriteTo.Console()
)