log level in development and production asp.net core 2.2

Question

i am using asp.net core mvc and web api project

which has below version

 <TargetFramework>netcoreapp2.2</TargetFramework>

i'm also using Microsoft.Extensions.Logging.ILogger to log some of information

for Example : _logger.LogInformation("special information log for xyz method"); for application insight.

so as per this post https://weblog.west-wind.com/posts/2018/Dec/31/Dont-let-ASPNET-Core-Default-Console-Logging-Slow-your-App-down

i made log level like this in my local app setting project and hit play icon from visual studio and watching console logs in black window.

"LogLevel": {
      "Default": "Information",
      "System": "Warning",
      "Microsoft": "Warning"
    }

now when i do run of my application, still i'm able to see logs like this

info: Microsoft.AspNetCore.Hosting.Internal.WebHost[2]
      Request finished in 35782.1232ms 200 text/html; charset=UTF-8
info: Microsoft.AspNetCore.Hosting.Internal.WebHost[1]
      Request starting HTTP/1.1 GET http://localhost:57526/polyfills.js
info: Microsoft.AspNetCore.Hosting.Internal.WebHost[1]
      Request starting HTTP/1.1 GET http://localhost:57526/styles.js
info: Microsoft.AspNetCore.Hosting.Internal.WebHost[1]
      Request starting HTTP/1.1 GET http://localhost:57526/vendor.js

Question #1 : why still i'm able to to see this log in console window where "info is from Microsoft" :(

Question #2 : what is your best recommendation(experiences) log level for production and development? i do not want to slow down my application due to wanted to log information logged to application insights.

program.cs

                    // Optional: Apply filters to control what logs are sent to Application Insights.
                    // The following configures LogLevel Information or above to be sent to
                    // Application Insights for all categories.
                    logging.AddFilter<Microsoft.Extensions.Logging.ApplicationInsights.ApplicationInsightsLoggerProvider>
                                 ("", LogLevel.Information);

                }
            }
        );

Ryan Ryan · Accepted Answer · 2019-11-28T01:45:20

Question #1 : why still i'm able to to see this log in console window where "info is from Microsoft" :

Since you see the logging in development,you need to change log levels in appsettings.Development.json instead of appsettings.json, you could find the file just behind the appsettings.json.

Question #2 : what is your best recommendation(experiences) log level for production and development? i do not want to slow down my application due to wanted to log information logged to application insights.

It is documented well, refer to https://docs.microsoft.com/en-us/aspnet/core/fundamentals/logging/?view=aspnetcore-3.0#log-level

In production: Logging at the Trace through Information levels produces a high-volume of detailed log messages. To control costs and not exceed data storage limits, log Trace through Information level messages to a high-volume, low-cost data store. Logging at Warning through Critical levels typically produces fewer, smaller log messages. Therefore, costs and storage limits usually aren't a concern, which results in greater flexibility of data store choice.

During development: Log Warning through Critical messages to the console. Add Trace through Information messages when troubleshooting.

log level in development and production asp.net core 2.2

1 Answers