NLog: Appsettings layout render not work in .NET Core 2.2 and IIS in process hosting

Hello,

we get exception when we run NLog in .NET Core 2.2 and inprocess hosting in IIS.

Exception: Error Error parsing layout appsettings will be ignored. Exception: System.Reflection.TargetInvocationException: Exception has been thrown by the target of an invocation. —> System.IO.FileNotFoundException: The configuration file ‘appsettings.json’ was not found and is not optional. The physical path is ‘c:\windows\system32\inetsrv\appsettings.json’.

NLog version: 4.5.11 NLog.Web.AspNetCore version: 4.7.1

Platform: .NET Core 2.2

Current NLog config (xml or C#, if relevant)

<nlog>
  <targets>
        <target xsi:type="Mail" name="Errors"
                subject="Unhandled Error"
                body="Timestamp: ${longdate:universalTime=true}${newline}Message: ${message}${newline}${appsettings:name=aplicationName}"
                to="..."
                from="..."
                smtpServer=".."
                smtpPort="25"/>
  </targets>
</nlog>

What is the current result? Target is completly ignored
What is the expected result? Target works
Are there any workarounds? yes/no Yes, host app out of IIS process, or set values directly in nlog.config

About this issue

Original URL
State: closed
Created 5 years ago
Comments: 21 (14 by maintainers)

Most upvoted comments

OK I think I found the problem

for some reasons VS 2017 won’t always (but sometimes it does) update my nlog.config in bin folder (e.g. bin\Debug\netcoreapp2.2), so be warned.

you need this:

1: in nlog.config

<extensions>
    <add assembly="NLog.Extensions.Logging"/>
</extensions>

2: and for some reason you also need to install the “NLog.Extensions.Logging” package directly:

<PackageReference Include="NLog.Extensions.Logging" Version="1.4.0" />

Not sure why the latter is needed… (it’s the same version as the dependency of NLog.Web.AspNetCore Version 4.8.0

so total:

<ItemGroup>
    <PackageReference Include="Microsoft.AspNetCore.App" />
    <PackageReference Include="NLog.Extensions.Logging" Version="1.4.0" />
    <PackageReference Include="NLog.Web.AspNetCore" Version="4.8.0" />
    <PackageReference Include="NLog" Version="4.5.11" />
</ItemGroup>

304NotModified on Feb 14, 2019

Issue you might have with custom layout-renders should probably be reported to the correct owner:

https://github.com/linmasaki/NLog.Appsettings.Standard

But I can recommend that you stop using ${appsettings}, but instead upgrade to NLog.Web.AspNetCore ver. 4.8.0 and use the ${configsetting}:

https://github.com/NLog/NLog/wiki/ConfigSetting-Layout-Renderer

snakefoot on Feb 3, 2019

NLog.Web.AspNetCore ver 4.9.3 has been released, and now you can do this:

var logger = NLog.LogManager.Setup().LoadConfigurationFromAppSettings().GetCurrentClassLogger();

That replaces the old style:

var logger = NLog.Web.NLogBuilder.ConfigureNLog("nlog.config").GetCurrentClassLogger();

snakefoot on Aug 8, 2020

@StefH Thank you for pointing out the clunky way of handling appsettings together with NLog.config. Created https://github.com/NLog/NLog.Extensions.Logging/issues/265 about improving this.

snakefoot on Mar 11, 2019