Changing loglevel in appsettings.json won't get applied to NLog

Question

I am using NLog with dotnet core app configured like described here. https://github.com/NLog/NLog.Web/wiki/Getting-started-with-ASP.NET-Core-2

In nlog.config if I set minLevel to Error and launch my app I can see on logger that logDebug is disabled.

If I restore back to trace then all levels are set to true (error, trace, debug, info, warning)

and if I put this into config file (appsettings.json)

"Logging": {
        "LogLevel": {
            "Default": "Error",
            "Microsoft": "Information"
        }
    }

then nothing happens, all logger levels are still set to true, what might be wrong ?

Answer 1

As Snakefoot mentioned,

this is the config of Microsoft Extension Logging.

When using NLog + Injected .NET Core loggers (using Microsoft Extension Logging), the flow is as follows:

ILogger<MyClass> → LoggerFactory in Microsoft Extension Logging → LogFactory in NLog.

To configure NLog, you should update the NLog <rules> in your nlog.config, e.g.

(also possible from code, see docs)

<rules>
   <logger name="*" minlevel="debug" />
</rules>

Please note that you won't see debug logs if the minlevel is "debug" in NLog and "error" the appsettings.json

note 2: When using NLog direct, e.g. the NLog.LogManager.GetCurrentClassLogger(), you only need to configure NLog and the appsettings.json config isn't used for those logs.