Logging in .Net Core 7 Web App

Recently I have upgraded .Net Core Web API project which was written in .Net Core 2.2 to .Net version 8.

It is a quite a jump, so had to re-write few classes to get it working.

When it finally runs, I realized that logging is not working on the upgraded app. App use to log to Windows Event Log.

Reading through this article, I found out there are few things need changing.

First of all .Net 8, web apps starts with WebApplication.CreateBuilder method. By default this method adds following logging providers:

• Console
• Debug
• EventSource
• EventLog (of course this only works on Windows platforms)

So, by default EventLog is added, but why didn't I get logging output? I have tried putting EventLog settings on applicationSettings.json, but didn't work.

Reading through above article, I noticed that you need to specify settings on code level:

var builder = WebApplication.CreateBuilder();

builder.Logging.AddEventLog(eventLogSettings =>

{

    eventLogSettings.SourceName = "MyLogs";

    eventLogSettings.LogName = "Application";

});

Once this is added logging started to work. 

Note that if you don't specify "SourceName", it is defaulted to ".NET Runtime". So if you need to say source on the Windows Event log to say custom name, it need to specify above code. 

Also make sure you have created the Event Source before starting to logging to Windows Event log. I use following powershell command to add event source to Windows Event Log.

New-EventLog -source <<your source name>> -LogName Application

One other thing you need to pay attention is logging level. Logging level can be specified in code or in applicationSettings.json file.

As explained in above article - "Unlike the other providers, the EventLog provider does not inherit the default non-provider settings. If EventLog log settings aren't specified, they default to LogLevel.Warning."