Can I configure an interceptor in EntityFramework Core?

Question

In the old (pre .net core) era\'s entity framework 6 as shown in this blog post there is a way to configure an interceptor which can log all slow queries including a stack b

Answer 1

Here is an example found on github from ajcvickers on how to use an Interceptor in EF CORE (2.2 at the time of answering this question):

public class NoLockInterceptor : IObserver>
{
    public void OnCompleted()
    {
    }

    public void OnError(Exception error)
    {
    }

    public void OnNext(KeyValuePair value)
    {
        if (value.Key == RelationalEventId.CommandExecuting.Name)
        {
            var command = ((CommandEventData)value.Value).Command;

            // Do command.CommandText manipulation here
        }
    }
}

Next, create a global listener for EF diagnostics. Something like:

public class EfGlobalListener : IObserver
{
    private readonly NoLockInterceptor _noLockInterceptor = new NoLockInterceptor();

    public void OnCompleted()
    {
    }

    public void OnError(Exception error)
    {
    }

    public void OnNext(DiagnosticListener listener)
    {
        if (listener.Name == DbLoggerCategory.Name)
        {
            listener.Subscribe(_noLockInterceptor);
        }
    }
}

And register this as part of application startup:

DiagnosticListener.AllListeners.Subscribe(new EfGlobalListener());