Remove console and debug loggers in ASP.NET Core 2.0 when in production mode

Question

In ASP.NET Core 2.0 we have this

public static IWebHost BuildWebHost(string[] args) =>     WebHost.CreateDefaultBuilder(args)         .UseStartup<Startup>()         .Build(); 

That CreateDefaultBuilder(args) has many helpful defaults. However it contains this:

.ConfigureLogging((context, logging) => {     logging.AddConfiguration(context.Configuration.GetSection("Logging"));     logging.AddConsole();   // HERE IS THE PROBLEM     logging.AddDebug();     // HERE IS THE PROBLEM }) 

So the console and debug logging providers are always registered.

I used to register them like this

if (env.IsDevelopment()) {      // register them here } 

How do I remove/unregister them when running in production mode? I don't mean changing the logging level, I mean I don't want them registered at all in production mode.

Answer 1

I would say the designed way to do this would be by changing the logging configuration not to log anything to those providers. But I understand that you want to remove any calls for production; and you can still do this properly in code.

You can simply access the hosting environment from the HostBuilderContext that gets passed to the ConfigureLogging lambda:

.ConfigureLogging((context, logging) => {     logging.AddConfiguration(context.Configuration.GetSection("Logging"));      if (context.HostingEnvironment.IsDevelopment())     {         logging.AddConsole();         logging.AddDebug();     } }); 

Obviously, this alone does not help to undo what the CreateDefaultBuilder call already set up. First, you would need to unregister those providers. For that, you can use the new ILoggingBuilder.ClearProviders method:

.ConfigureLogging((context, logging) => {     // clear all previously registered providers     logging.ClearProviders();      // now register everything you *really* want     // … }); 

This was introduced in response to this logging issue on GitHub.