Logging based on environment in .NetCore 2.2 using ILoggerProvider

Question

I am working on .Net Core 2.2 logging mechanism. While I was experimenting the logging based on environment. So, I created two new appSettings.json files with respective environments along with appSettings.json present in the solution. One for Development, other for Production environment.

appsettings.json
{
  "Logging": {
    "LogLevel": {
      //"Default": "Debug",
      //"System": "Information",
      //"Microsoft": "Error"
    }
  }
}

appsettings.Development.json

{
  "Logging": {
    "LogLevel": {
     "Microsoft": "Information"
    }
  }
}

appSettings.Production.json

 {
  "Logging": {
    "Console": {
      "LogLevel": {
        "Microsoft": "Critical"
      }
    }
  }
}

Changed the StartUp.cs file

public Startup(IConfiguration configuration, IHostingEnvironment env)
{

            Configuration = configuration;
            var currentEnvironment = env.EnvironmentName;
            var builder = new ConfigurationBuilder()
                .SetBasePath(env.ContentRootPath)
                .AddJsonFile("appsettings.json", optional: true, reloadOnChange: true)
                .AddJsonFile($"appsettings.{currentEnvironment}.json", optional: true);

}

Logging Method

public void LogExceptionToConsole()
{
            _logger.LogError("This is raised by error");
            _logger.LogCritical("This is raised by critical ");
}

And launchSettings.json

{
  "iisSettings": {
    "windowsAuthentication": false, 
    "anonymousAuthentication": true, 
    "iisExpress": {
      "applicationUrl": "http://localhost:2131",
      "sslPort": 44388
    }
  },
  "profiles": {
    "IIS Express": {
      "commandName": "IISExpress",
      "launchBrowser": true,
      "environmentVariables": {
        "ASPNETCORE_ENVIRONMENT": "Production"
      }
    },
    "DemoLoggingApplication": {
      "commandName": "Project",
      "launchBrowser": true,
      "applicationUrl": "https://localhost:5001;http://localhost:5000",
      "environmentVariables": {
        "ASPNETCORE_ENVIRONMENT": "Development"
      }
    }
  }
}

I understand that environment specific appSettings would be taken the highest precedence. And I have two questions

1) Does environment specific logging happens? If yes, then what could be the changes in the above logic.

2) When I ran the application in Development mode on DemoLoggingApplication profile. I can see all the Information,Error & Critical logs.

But when I changed the ASPNETCORE_ENVIRONMENT value from Development to Production for DemoLoggingApplication profile and ran the application I could again see both the logs of type Error & Critical. As, I've set that Console provider should only display Critical logs of type Microsoft category .I've been displayed Errors logs also.

Though I've read the Microsoft documents, I couldn't understand the prioritization. Could anyone explain me detail why I'm seeing both the logs. Am I missing any understanding. Please help me.

Thanks in advance

Updated the question after Bob's answer It worked after changing the appsettings.json, appsettings.Development.json & appSettings.Production.json

appSettings.json

{
  "Logging": {
    "LogLevel": {
      "Default": "Information" 
    }
  }
}

appsettings.Development.json

{
  "Logging": {
    "Console": {
      "LogLevel": {
        "Microsoft": "Information",
        "Default": "Information" // newly
      }
    }
  }
}

appSettings.Production.json

{
  "Logging": {
    "Console": {
      "LogLevel": {
        "Microsoft": "Critical",
        "Default" :  "Critical" // newly added line
      }
    }
  }
}

Now when I changed the environment to Development, I could log from Information but only after adding Default category to both Development and Production.

I just wanted to know why is this behavior? And what's the impact of having maintaining appsettings.json -> Logging when we are having Development & Production settings.

Thanks

Initially in your appsettings.json all loglevels including default are commented. That is why you are not seeing the use of having appsettings.json — Bob Ash
Is it mandatory to have Default category in every provider? What happens if it's not given? — Vijay
It's not mandatory. For a given Log Category if LogLevel is not mentioned in code/config, then it will look for LogLevel of Default Log Category in code/config. If that is also not available, then it takes Minimum Log Level setting as "Information". — Bob Ash

Bob Ash Bob Ash · Accepted Answer · 2020-02-04T11:19:57

Environment specific logging happens.

In your example, both appsettings.Development.json and appsettings.Production.json defines LogLevel only for "Microsoft" category. But, the logging done from your code falls in a different Log Category whose LogLevel is not defined in code/config files. Hence, it takes default minimum log level as "Information" in both environments.

To see a difference, add "Default" key with different LogLevel settings in different environments as below:

appsettings.Development.json

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

appSettings.Production.json

 {
  "Logging": {
    "Console": {
      "LogLevel": {
        "Microsoft": "Critical",
         "Default": "Critical"
      }
    }
  }
}

Logging based on environment in .NetCore 2.2 using ILoggerProvider

1 Answers