WebApplication.CreateBuilder ignores Logging:EventLog:SourceName

[KeithHenry]

Is there an existing issue for this?

• I have searched the existing issues

Describe the bug

WebApplication.CreateBuilder checks for whether it is running on Windows, and if it is then it calls AddEventLog() with settings from Logging:EventLog

If you set Logging:EventLog:LogLevel those settings are honoured.

If you set Logging:EventLog:SourceName in appsettings.json it is ignored, logs write as ".NET Runtime".

I can work around this by manually re-registering the event logger provider:

    [System.Runtime.Versioning.SupportedOSPlatform("windows")]
    public static void SetEventLogConfig(WebApplicationBuilder builder) {
        string? eventLog = builder.Configuration["Logging:EventLog:SourceName"];
        if(eventLog is not null)
            builder.Logging.AddEventLog(c => c.SourceName = eventLog);
    }

// then in program.cs
var builder = WebApplication.CreateBuilder(args);
...
if(RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
    SetEventLogConfig(builder);

Expected Behavior

If you set Logging:EventLog:SourceName it should be used by the logging provider.

Either WebApplication.CreateBuilder should pick up the appsettings.json for AddEventLog(), or it should not call it at all.

Some better documentation on what is supported in this logger would be extremely helpful.

Steps To Reproduce

• Create any basic project with .NET 6 or above's WebApplication.CreateBuilder
• Add a call after app = builder.Build() to app.Logger.LogCritical("test message").
• Add this to appsettings.json:

  "Logging": {
    "EventLog": {
      "LogLevel": {
        "Default": "Warning"
      },
      "SourceName": "testLog"
    }
  }

• Register the new log source on the server with:

new-eventlog -LogName Application -source testLog

• Run your app
• Check Event Viewer > Application and the "test message" will be under ".NET Runtime", they should be under source "testLog"

Exceptions (if any)

None

.NET Version

7.0.101

Anything else?

Tested with VS 2022 and VSCode on different machines, but mine has:

dotnet --info
.NET SDK:
 Version:   7.0.101
 Commit:    bb24aafa11

Runtime Environment:
 OS Name:     Windows
 OS Version:  10.0.19045
 OS Platform: Windows
 RID:         win10-x64
 Base Path:   C:\Program Files\dotnet\sdk\7.0.101\

Host:
  Version:      7.0.1
  Architecture: x64
  Commit:       97203d38ba

.NET SDKs installed:
  2.1.700 [C:\Program Files\dotnet\sdk]
  2.1.701 [C:\Program Files\dotnet\sdk]
  2.1.818 [C:\Program Files\dotnet\sdk]
  2.2.401 [C:\Program Files\dotnet\sdk]
  5.0.100 [C:\Program Files\dotnet\sdk]
  6.0.304 [C:\Program Files\dotnet\sdk]
  6.0.307 [C:\Program Files\dotnet\sdk]
  7.0.100 [C:\Program Files\dotnet\sdk]
  7.0.101 [C:\Program Files\dotnet\sdk]

.NET runtimes installed:
  Microsoft.AspNetCore.All 2.1.11 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
  Microsoft.AspNetCore.All 2.1.12 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
  Microsoft.AspNetCore.All 2.1.13 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
  Microsoft.AspNetCore.All 2.1.30 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
  Microsoft.AspNetCore.All 2.2.6 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
  Microsoft.AspNetCore.App 2.1.11 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 2.1.12 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 2.1.13 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 2.1.30 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 2.2.6 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 5.0.0 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 5.0.17 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 6.0.11 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 6.0.12 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 7.0.0 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 7.0.1 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.NETCore.App 2.1.11 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 2.1.12 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 2.1.13 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 2.1.30 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 2.2.6 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 3.1.32 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 5.0.0 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 5.0.17 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 6.0.11 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 6.0.12 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 7.0.0 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 7.0.1 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.WindowsDesktop.App 3.1.32 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
  Microsoft.WindowsDesktop.App 5.0.0 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
  Microsoft.WindowsDesktop.App 5.0.17 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
  Microsoft.WindowsDesktop.App 6.0.11 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
  Microsoft.WindowsDesktop.App 6.0.12 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
  Microsoft.WindowsDesktop.App 7.0.0 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
  Microsoft.WindowsDesktop.App 7.0.1 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]

Other architectures found:
  arm64 [C:\Program Files\dotnet]
    registered at [HKLM\SOFTWARE\dotnet\Setup\InstalledVersions\arm64\InstallLocation]
  x86   [C:\Program Files (x86)\dotnet]
    registered at [HKLM\SOFTWARE\dotnet\Setup\InstalledVersions\x86\InstallLocation]

I couldn't figure out the best area label to add to this issue. If you have write-permissions please help me learn by adding exactly one area label.

[KeithHenry]

@dotnet-issue-labeler I don't, but I'd guess [area-Extensions-Logging]

Tagging subscribers to this area: @dotnet/area-extensions-logging
See info in area-owners.md if you want to be subscribed.

Issue Details

---

Is there an existing issue for this?

• I have searched the existing issues

Describe the bug

WebApplication.CreateBuilder checks for whether it is running on Windows, and if it is then it calls AddEventLog() with settings from Logging:EventLog

If you set Logging:EventLog:LogLevel those settings are honoured.

If you set Logging:EventLog:SourceName in appsettings.json it is ignored, logs write as ".NET Runtime".

I can work around this by manually re-registering the event logger provider:

    [System.Runtime.Versioning.SupportedOSPlatform("windows")]
    public static void SetEventLogConfig(WebApplicationBuilder builder) {
        string? eventLog = builder.Configuration["Logging:EventLog:SourceName"];
        if(eventLog is not null)
            builder.Logging.AddEventLog(c => c.SourceName = eventLog);
    }

// then in program.cs
var builder = WebApplication.CreateBuilder(args);
...
if(RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
    SetEventLogConfig(builder);

Expected Behavior

If you set Logging:EventLog:SourceName it should be used by the logging provider.

Either WebApplication.CreateBuilder should pick up the appsettings.json for AddEventLog(), or it should not call it at all.

Some better documentation on what is supported in this logger would be extremely helpful.

Steps To Reproduce

• Create any basic project with .NET 6 or above's WebApplication.CreateBuilder
• Add a call after app = builder.Build() to app.Logger.LogCritical("test message").
• Add this to appsettings.json:

  "Logging": {
    "EventLog": {
      "LogLevel": {
        "Default": "Warning"
      },
      "SourceName": "testLog"
    }
  }

• Register the new log source on the server with:

new-eventlog -LogName Application -source testLog

• Run your app
• Check Event Viewer > Application and the "test message" will be under ".NET Runtime", they should be under source "testLog"

Exceptions (if any)

None

.NET Version

7.0.101

Anything else?

Tested with VS 2022 and VSCode on different machines, but mine has:

dotnet --info
.NET SDK:
 Version:   7.0.101
 Commit:    bb24aafa11

Runtime Environment:
 OS Name:     Windows
 OS Version:  10.0.19045
 OS Platform: Windows
 RID:         win10-x64
 Base Path:   C:\Program Files\dotnet\sdk\7.0.101\

Host:
  Version:      7.0.1
  Architecture: x64
  Commit:       97203d38ba

.NET SDKs installed:
  2.1.700 [C:\Program Files\dotnet\sdk]
  2.1.701 [C:\Program Files\dotnet\sdk]
  2.1.818 [C:\Program Files\dotnet\sdk]
  2.2.401 [C:\Program Files\dotnet\sdk]
  5.0.100 [C:\Program Files\dotnet\sdk]
  6.0.304 [C:\Program Files\dotnet\sdk]
  6.0.307 [C:\Program Files\dotnet\sdk]
  7.0.100 [C:\Program Files\dotnet\sdk]
  7.0.101 [C:\Program Files\dotnet\sdk]

.NET runtimes installed:
  Microsoft.AspNetCore.All 2.1.11 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
  Microsoft.AspNetCore.All 2.1.12 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
  Microsoft.AspNetCore.All 2.1.13 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
  Microsoft.AspNetCore.All 2.1.30 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
  Microsoft.AspNetCore.All 2.2.6 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
  Microsoft.AspNetCore.App 2.1.11 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 2.1.12 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 2.1.13 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 2.1.30 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 2.2.6 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 5.0.0 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 5.0.17 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 6.0.11 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 6.0.12 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 7.0.0 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 7.0.1 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.NETCore.App 2.1.11 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 2.1.12 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 2.1.13 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 2.1.30 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 2.2.6 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 3.1.32 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 5.0.0 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 5.0.17 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 6.0.11 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 6.0.12 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 7.0.0 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 7.0.1 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.WindowsDesktop.App 3.1.32 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
  Microsoft.WindowsDesktop.App 5.0.0 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
  Microsoft.WindowsDesktop.App 5.0.17 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
  Microsoft.WindowsDesktop.App 6.0.11 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
  Microsoft.WindowsDesktop.App 6.0.12 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
  Microsoft.WindowsDesktop.App 7.0.0 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
  Microsoft.WindowsDesktop.App 7.0.1 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]

Other architectures found:
  arm64 [C:\Program Files\dotnet]
    registered at [HKLM\SOFTWARE\dotnet\Setup\InstalledVersions\arm64\InstallLocation]
  x86   [C:\Program Files (x86)\dotnet]
    registered at [HKLM\SOFTWARE\dotnet\Setup\InstalledVersions\x86\InstallLocation]

Author:	KeithHenry
Assignees:	-
Labels:	untriaged, area-Extensions-Logging
Milestone:	-

[KeithHenry]

What's happening on this? It's been 6 months.

[tramhuynhtd]

Hi, Is there any update on this?

[RayKoopa]

Any update would be appreciated, setting up Windows Event Log logging has always been a painful experience to me from "silent failures" when setting it up (for example, setting LogName requiring admin rights, or settings SourceName preventing all logging, or not being respected at all as laid out in this issue).

[xemed-ahope]

IMHO, the main problem is that there's no obvious way to discover the mechanism intended for the desired use case. The workaround in the issue description isn't required. As implemented, EventLogSettings can either be hardcoded (as a concrete instance or Action<EventLogSettings>) or drawn from configuration via the options pattern. The former is perfectly clear from the AddEventLog overloads, but the latter requires an extra, unintuitive step.

The "missing" step is registering IOptions<EventLogSettings> explicitly. That may not be best handled with an additional overload, but does at least merit a comment in the minimal AddEventLog overload.

public const string EventLogConfigSectionPath = "Logging:EventLog";

/// <inheritdoc cref="EventLoggerFactoryExtensions.AddEventLog(ILoggingBuilder)"/>
/// <param name="useOptions">Whether to bind EventLogSettings via the options pattern</param>
public static ILoggingBuilder AddEventLog(this ILoggingBuilder builder, bool useOptions)
{
    if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
    {
        if (useOptions)
            builder.Services.AddOptions<EventLogSettings>().BindConfiguration(EventLogConfigSectionPath);
        builder.AddEventLog();
    }
    return builder;
}

One caveat with the IOptions<EventLogSettings> setup to keep in mind is that AddWindowsService (and UseWindowsService) supply a sensible default value for SourceName by injecting a IConfigureOptions<EventLogSettings>. I mention it because injecting my own default was my next stumbling block! Easy to work around that once you know.