Overriding appsettings.json with environment variable causes duplicated NLog output

[mbcrawfo]

Type: Bug

NLog version: 4.6.7
NLog.Extensions.Logging version: 1.5.1
NLog.Web.AspNetCore version: 4.8.4

Platform: .NET Core 2.2

Current NLog config

{
  "NLog": {
    "extensions": {
      "NLog.Extensions.Logging": {
        "assembly": "NLog.Extensions.Logging"
      },
      "NLog.Web.AspNetCore": {
        "assembly": "NLog.Web.AspNetCore"
      }
    },
    "targets": {
      "console": {
        "type": "Console",
        "layout": "${level} | ${message}"
      }
    },
    "rules": {
      "console": {
        "logger": "*",
        "minLevel": "Trace",
        "writeTo": "console"
      }
    }
  }
}

I made a simple app based on the .Net Core API project template to reproduce the issue: https://github.com/mbcrawfo/nlog-dup

When you start the app, you'll notice that the messages written by NLog are duplicated four times:

If you modify launchSettings.json to remove the NLOG__RULES__CONSOLE__MINLEVEL environment variable, messages are only written once. Based on the internal config logging, it looks like the console rule is actually being processed four times:

[304NotModified]

Isn't here the issue that Microsoft is also writing to console by default?

[mbcrawfo]

@304NotModified if you review Program.cs in the app I linked you'll see that the default providers are cleared:

var host = WebHost.CreateDefaultBuilder(args)
    .UseStartup<Startup>()
    .ConfigureLogging(
        logging =>
        {
            logging.ClearProviders();
            logging.SetMinimumLevel(LogLevel.Trace);
        }
    )
    .UseNLog()
    .Build();

NLog internal logging also shows four targets attached to each logger:

[snakefoot]

Looks like the casing of the environment-variable is important when merging json with environment variables.

This launchSettings.json works:

{
  "$schema": "http://json.schemastore.org/launchsettings.json",
  "profiles": {
    "Kestrel": {
      "commandName": "Project",
      "launchBrowser": false,
      "applicationUrl": "http://localhost:5000",
        "environmentVariables": {
            "ASPNETCORE_ENVIRONMENT": "Development",
            "NLog__rules__console__minLevel": "Info"
        }
    }
  }
}

Don't know if this is a bug in MEL-Config, or if NLogLoggingConfiguration needs to support duplicate keys/paths but with different casing (will be some ugly code)

Maybe ask Microsoft if there is a setting to make the merge of MEL-config-provider case-insensitive?

[304NotModified]

superseded by #321?

[304NotModified]

Closing this as this is an external issue