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Nlog logs location overwritten by code still logging happening at config location

NLog version - 4.4.3
Platform - .Net 4.5.2
Current NLog config -
<nlog autoReload="true" xmlns="http://www.nlog-project.org/schemas/NLog.xsd" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
<variable name="layout" value="${longdate}|${level:uppercase=true}|${threadid}|${logger}|${message}" />
<variable name="logLocation" value="logs" />
<targets async="true">
<target name="debugger" xsi:type="Debugger" layout="${layout}" />
<target name="console" xsi:type="Console" layout="${layout}" />
<target name="logfile"
xsi:type="File"
fileName="${logLocation}\${processname}.log"
archiveFileName="${logLocation}\\${processname}.{###}.log"
archiveEvery="Day"
archiveAboveSize="2048000"
archiveNumbering="Rolling"
maxArchiveFiles="10"
concurrentWrites="false"
keepFileOpen="false"
layout="${layout}" />
</targets>
<rules>
<logger name="*" minlevel="Info" writeTo="logfile" />
<logger name="*" minlevel="Debug" writeTo="debugger" />
<logger name="*" minlevel="Info" writeTo="console" />
</rules>
</nlog>
Code to override location
LogManager.ReconfigExistingLoggers();
var target = (FileTarget)LogManager.Configuration.FindTargetByName<AsyncTargetWrapper>("logfile").WrappedTarget;
target.FileName = $#"..\..\..\..\logs\Foobar.log";
What is the current result?
When application/service starts it writes to overwritten location, but sometimes (not sure of scenario - maybe rollover) it start writing to config location.
What is the expected result?
Logs should always be written to overwritten location.
Did you checked the Internal log?
No
Please post full exception details (message, stacktrace, inner exceptions)
No Exception
Are there any workarounds? yes/no
Restart service/application.
Is there a version in which it did work?
No idea. This is the version we started with and sticking to.
Can you help us by writing an unit test?
Unit tests won't help as it is an intermittent scenario.

You have auto reload (<nlog autoReload="true”) enabled, so if it needs to reload (after sleep or change in config), you will lose the changes made in code.
The solution it so disable autoreload, or set the change after reload again. See code example:
static void Main(string[] args)
{
UpdateNLogConfig();
LogManager.ConfigurationReloaded += LogManager_ConfigurationReloaded;
log.Info("Entering Application.");
Console.WriteLine("Press any key to exit ...");
Console.Read();
}
private static void LogManager_ConfigurationReloaded(object sender, LoggingConfigurationReloadedEventArgs e)
{
UpdateNLogConfig();
}
private static void UpdateNLogConfig()
{
//note: don't set LogManager.Configuration because that will overwrite the nlog.config settings
var target = (FileTarget)LogManager.Configuration.FindTargetByName<AsyncTargetWrapper>("logfile").WrappedTarget;
target.FileName = $#"..\..\..\..\logs\Foobar.log";
LogManager.ReconfigExistingLoggers();
}
See also Combine XML config with C# config · NLog/NLog Wiki

Instead of doing target lookup, and modifying target properties directly. Then I suggest making use of the NLog Layout Logic.
<nlog autoReload="true" xmlns="http://www.nlog-project.org/schemas/NLog.xsd" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
<targets async="true">
<target name="logfile"
xsi:type="File"
fileName="${gdc:item=logFile:whenEmpty=log/${processname}.log}" />
</targets>
<rules>
<logger name="*" minlevel="Info" writeTo="logfile" />
</rules>
</nlog>
And then just assign the logLocation:
NLog.GlobalDiagnosticsContext.Set("logFile", $#"..\..\..\..\logs\Foobar.log");
Using GDC will also works very well with autoReload=true and no need to call LogManager.ReconfigExistingLoggers().

NLog - Parameter for File Target FileName

I am using NLog in a .NET application. Currently, my config section in my App.config looks like this:
<nlog xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
<targets>
<target name="assemblyLogFile" xsi:type="File" fileName="${basedir}/logs/${shortdate}/assembly.log" createDirs="true" keepFileOpen="true" encoding="utf-8" layout="${longdate} ${message}${exception:format=ToString}"></target>
<target name="appLogFile" xsi:type="File" fileName="${basedir}/logs/app.log" createDirs="true" keepFileOpen="true" encoding="utf-8" layout="${longdate} ${message}${exception:format=ToString}"></target>
</targets>
<rules>
<logger name="Assembly" minlevel="Trace" writeTo="assemblyLogFile" />
<logger name="*" minlevel="Trace" writeTo="appLogFile" />
</rules>
</nlog>
My app is dynamically loading the assemblies. I would like to log each assemblies logs to their own file. In essence, I would like to update the filename attribute on the target element to something like this:
fileName="${basedir}/logs/${shortdate}/assembly.[Name].log"
In this pattern, "[Name]" is defined in the code. My question is, is there a way to programmatically pass a variable to a target via NLog? If so, how?

If you want this to be completely dynamic, I think you have two approaches.
1) Create a custom log factory and wrapper for NLog.ILogger that keeps track of and injects the assembly name into the NLog logEvent. This means all assemblies must use your logger factory, and not NLog directly.
2) Create a NLog extension that lets you access the assembly name as a layout variable, derived from the logger name. This works if you use the default LogManager.GetCurrentClassLogger() in all the assemblies.
Here is a naive caching renderer that uses reflection to find the correct assembly. You could probably make this more efficient by scanning assemblies when you load them - or maybe just do string wrangling on the logger name.
[NLog.LayoutRenderers.LayoutRenderer("assemblyName")]
public class AssemblyNameLayoutRenderer : NLog.LayoutRenderers.LayoutRenderer
{
static ConcurrentDictionary<string, string> loggerNameToAssemblyNameCache = new ConcurrentDictionary<string, string>();
protected override void Append(StringBuilder builder, LogEventInfo logEvent)
{
var fullClassName = logEvent.LoggerName;
var assemblyName = FindAssemblyNameFromClassName(fullClassName);
if (!string.IsNullOrEmpty(assemblyName))
builder.Append(assemblyName);
}
private string FindAssemblyNameFromClassName(string fullClassName)
{
return loggerNameToAssemblyNameCache.GetOrAdd(fullClassName, cl =>
{
var klass = (
from a in AppDomain.CurrentDomain.GetAssemblies()
from t in a.GetTypes()
where t.FullName == fullClassName
select t).FirstOrDefault();
return klass?.Assembly.GetName().Name;
});
}
}
And then use this in the config file like this:
<extensions>
<add assembly="AssemblyContainingCustomRenderer" />
</extensions>
<targets>
<target xsi:type="FilteringWrapper" name="assemblyLogFile" condition="'${assemblyName}' != ''">
<target name="realAssemblyLogFile" xsi:type="File" fileName="logs/${shortdate}/assembly.${assemblyName}.log" createDirs="true" keepFileOpen="true" encoding="utf-8" layout="${longdate} ${message}${exception:format=ToString}" /
</target>
</targets>

If the assembly being loaded creates the logger using NLog.LogManager.GetLogger("assemblyName"), then you can do this (Works best with NLog ver. 4.5 or higher):
<nlog xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
<targets>
<target name="assemblyLogFile" xsi:type="File" fileName="${basedir}/logs/${shortdate}/${logger}.log" createDirs="true" keepFileOpen="true" encoding="utf-8" layout="${longdate} ${message}${exception:format=ToString}"></target>
<target name="appLogFile" xsi:type="File" fileName="${basedir}/logs/app.log" createDirs="true" keepFileOpen="true" encoding="utf-8" layout="${longdate} ${message}${exception:format=ToString}"></target>
</targets>
<rules>
<logger name="AssemblyName" minlevel="Trace" writeTo="assemblyLogFile" />
<logger name="*" minlevel="Trace" writeTo="appLogFile" />
</rules>
</nlog>

Ignoring NLog Configuration referenced in other assembly

I have a unique problem with the NLog. I have a third-party assembly we use into our project. They have used the NLog into their project and referenced NLog configuration into their configuration which I don't have access to.
I initially had a problem even adding the NLog to a project since both version of dlls were different. I had to download the source code of NLog and change the assembly name since alias was not working for me (OR I didn't know how to use it.)
After giving my own assembly name, NLog started wotrking but.. It started logging third-party log information too with it. Looks like they were not careful enough when defining the logger and they just defined (*). Now my question is, how do I avoid their stuff from logging in to my file? I have also tried setting it to final = true.
Here is how my very simple configuration file looks like.
<?xml version="1.0" encoding="utf-8" ?>
<nlog xmlns="http://www.nlog-project.org/schemas/NLog.xsd"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
<!--
See https://github.com/nlog/nlog/wiki/Configuration-file
for information on customizing logging rules and outputs.
-->
<targets>
<!-- add your targets here -->
<!--
<target xsi:type="File" name="f" fileName="${basedir}/logs/${shortdate}.log"
layout="${longdate} ${uppercase:${level}} ${message}" />
-->
<target name="errorLog" xsi:type="File"
fileName="${basedir}/logs/error/${shortdate}.log"
layout="${longdate} ${uppercase:${level}} ${message}${onexception:${newline}EXCEPTION\: ${exception:format=ToString}}"
/>
<target name="generalLog" xsi:type="File"
fileName="C:/logs/${date:format=yyyy-MM-dd}.log"
layout="${longdate} ${uppercase:${level}} ${message}"/>
</targets>
<rules>
<!-- add your logging rules here -->
<logger name="Errors" writeTo="errorLog" minlevel="Warn"/>
<logger name="EBusiness.Model.*" writeTo="generalLog" levels="Trace,Debug,Info" final="true"/>
<!--
<logger name="*" minlevel="Trace" writeTo="f" />
-->
</rules>
</nlog>

If they are writing to the root logger, you should configure the root logger to not log to anywhere you care (maybe point it at a console logger) and your application can log to a specific logger which does write to your files.
Ugly, but should work.
For example:
Add this target:
<target name="console" xsi:type="Console" />
And Change the * rule to be:
<logger name="*" minlevel="Fatal " writeTo="console" />
Then, Add your own logger rule, say something like:
<logger name="MyNameSpace.*" minlevel="Trace" writeTo="logfile" final="true" />
Assuming you have a logfile target defined pointing at your file.

Send ALL messages to one log file, and RavenDB logs to a different log file

This sounds trivial, but I somehow cannot manage to do it. I have the below NLog.config
<?xml version="1.0" encoding="utf-8" ?>
<nlog xmlns="http://www.nlog-project.org/schemas/NLog.xsd" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" autoReload="true" throwExceptions="true">
<variable name="logDirectory" value="${basedir}/App_Data/logs"/>
<targets>
<target name="file" xsi:type="AsyncWrapper">
<target xsi:type="File" name="f1" fileName="${logDirectory}\log1.txt" layout="${longdate} ${callsite} ${level} ${message} (File 1)"/>
</target>
<target xsi:type="File" name="fileGeneral" fileName="${logDirectory}\log_${shortdate}.txt" >
<layout xsi:type="Log4JXmlEventLayout"/>
</target>
<target xsi:type="File" name="fileRaven" fileName="${logDirectory}\raven_${shortdate}.txt" >
<layout xsi:type="Log4JXmlEventLayout"/>
</target>
</targets>
<rules>
<logger name="Raven.*" minlevel="Trace" writeTo="fileRaven"></logger>
<logger name="*" minlevel="Trace" writeTo="fileGeneral"></logger>
</rules>
</nlog>
This is ending up with Raven + ALL logs to 'log_[date].txt', and another copy of just RavenDB logs in 'raven_[date].txt'. How should this be done?

<logger name="Raven.*" minlevel="Trace" writeTo="fileRaven" final="true"></logger>
Where final="true" means that no more rules for Raven.* will be executed will do what you are asking (if I understood you correctly).

Unfortunately this is not possible.
The reason is that the loggers are evaluated from top to bottom, the first one matching will be used, and does below will not be evaluated.
In you case this means that when logging anything Raven related the first logger will be used and stops the flow.

nLog missing log data

Sometime nLog is not logging all debug information (some of log.Debug... are missing in debug file), does anyone know why is this happening and how to avoid that?
Here is my nLog configuration
<nlog xmlns="http://www.nlog-project.org/schemas/NLog.xsd" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
<variable name="appTitle" value="Service"/>
<targets async="true">
<target name="fallbackDebug" xsi:type="FallbackGroup" returnToFirstOnSuccess="true">
<target xsi:type="File" fileName="C:\Logs\${date:format=yyyyMMdd}_Debug.txt" layout="..."/>
<target xsi:type="File" fileName="C:\Logs\${date:format=yyyyMMdd}_Debug_bu.txt" layout="..."/>
</target>
</targets>
<rules>
<logger name="*" levels="Trace,Debug,Error,Fatal" writeTo="fallbackDebug" />
</rules>
</nlog>
In code I'm using following
private static Logger log = LogManager.GetCurrentClassLogger();
...
log.Debug("Some debug info");
Thanks!

You must call LogManager.Flush() method at the end.
Example:
private static Logger log = LogManager.GetCurrentClassLogger();
...
log.Debug("Some debug info");
...
LogManager.Flush();