How to write to the Azure Log Stream

Question

I am trying to get achieve something similar to Console.WriteLine() in Azure Portal. From what I can find, you need to use System.Diagnostics.Trace for that. But I cannot get anything to show.

Here is what I have done:

I have configured the App Service logs to write to the filesystem like this:

And then I have made a simple end point, which tests three different ways of writing to the log:

[HttpGet]
public IActionResult WriteToLog()
{
    System.Diagnostics.Trace.TraceInformation("Getting all users... (TraceInformation)");
    System.Diagnostics.Trace.WriteLine("Getting all users... (Trace.WriteLine)");
    Console.WriteLine("Getting all users (Console.WriteLine)");

    return Ok();
}

But nothing show in the Log Stream when I am calling the end point. Am I missing something? I found this post where one of the answers mentions configuring AzureFileLoggerOptions, but I can't really find anything concrete about how or why you need this?

Answer 1

• By default, ASP.NET Core uses the Microsoft.Extensions.Logging.AzureAppServices logging provider.
• System.Diagnostics.Trace doesn't use configuration that .NET Core is built upon.
• If you really want to use System.Diagnostics.Trace, you'll have to add as a dependency yourself to your app.
• ILogger, which can write messages to Application Logs, can be used as a workaround for.NET core web applications.

 public void Configure(IApplicationBuilder app, IHostingEnvironment env, ILoggerFactory loggerFactory)
        {
           //your other code

            //add the following 2 lines of code.
            loggerFactory.AddConsole();
            loggerFactory.AddDebug();

            app.UseStaticFiles();

            //your other code
       }

Please refer Logging in .NET Core for more information