Write log in file in asp net core


ASP.NET is a popular programming language used for building web . One common requirement in web development is to write logs to a file. In this article, we will explore how to write logs in a file using ASP.NET Core.

in ASP.NET Core

ASP.NET Core provides a built-in logging framework that allows developers to easily log to various targets, files. The logging framework is extensible and supports different logging providers such as console, debug, event log, and file.

Configuring Logging

To configure logging in ASP.NET Core, you need to modify the appsettings.json file. Open the file and add the following configuration:

  "Logging": {
    "LogLevel": {
      "Default": "Information",
      "Microsoft": "Warning",
      "Microsoft.Hosting.": "Information"
    "File": {
      "Path": "logs/log.txt",
      "Append": true,
      "MaxFileSize": 10485760,
      "MaxFiles": 5

In the above configuration, we set the log level to “Information” by default. We also specify the file path where the logs will be , whether to append to the existing file, the maximum file size, and the maximum number of files to keep.

Writing Logs

Once the logging is configured, you can start writing logs in your ASP.NET Core application. Here's an example of how to write a log message:

using Microsoft.Extensions.Logging;

public class HomeController : Controller
    private readonly ILogger _logger;

    public HomeController(ILogger logger)
        _logger = logger;

    public IActionResult Index()
        _logger.LogInformation("This is an information log message.");

In the above example, we inject the ILogger into the HomeController class. We then use the logger to write an information log message using the LogInformation method.

Viewing Logs

After your ASP.NET Core application, you can view the logs in the specified file. Open the log.txt file located in the logs folder to see the messages.


Logging is an essential part of any application, including ASP.NET Core web applications. By configuring the logging framework and using the ILogger interface, you can easily write logs to a file. This allows you to track and debug your application effectively.

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