NLog: How to exclude specific loggers from a specific rule

nlog

In my NLog configuration, I have a catch-all logger but a specific logger I have created is very spammy and I want its output to go to its own file. That part is easy, but the catch-all logger receives the spammy log messages as well. How do I tell the main logger to log everything but to exclude the spammy logger?

I'm using NLog 2.0.

Best Answer

I think something like this is what you want:

<logger name="SpammyLogger" minlevel="Off" maxlevel="Trace" final="true" />  
<logger name="SpammyLogger" minlevel="Debug" maxlevel="Fatal" writeTo="SpammyFileTarget" final="true" />  
<logger name="*" levels="Trace" writeTo="RegularFileTarget/" />

Adding final="true" means that no more rules will be executed for the events produced by "SpammyLogger", but it applies only to the specified levels.(see https://github.com/nlog/nlog/wiki/Configuration-file#rules)

See this link for more NLog info that you might find helpful:

Most useful NLog configurations

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C# – How to log System.Diagnostics.Trace and System.Diagnostics.Debug messages to NLog file

You've configured a TraceSource to log to NLog, but your trace statement isn't using that TraceSource.

Try:

<system.diagnostics>
    <trace>
      <listeners>
          <add name="nlog" type="NLog.NLogTraceListener, NLog" />
      </listeners>
    </trace>
</system.diagnostics>

Or use the TraceSource you've configured, for example:

TraceSource source = new TraceSource("MyAppNamespace");
source.TraceEvent(TraceEventType.Warning, 2, "File Test not found");

C# – How to force reload of NLog configuration file

Actually, you've got an error in your code: LogManager.Configuration.Reload() does not change configuration of logger, but loads configuration from NLog.config file, deserializes it and returns LoggingConfiguration as a result.

to restore configuration, you need to do something like this:

LogManager.Configuration = LogManager.Configuration.Reload();
LogManager.ReconfigExistingLoggers();

here is a test example (minLevel in example config = "DEBUG"):

[TestMethod]
        public void Test()
        {
            Logger.Trace("TRACE 1");
            Logger.Debug("DEBUG 1");
            Logger.Warn("WARN 1");

            foreach (LoggingRule rule in LogManager.Configuration.LoggingRules)
            {
                rule.DisableLoggingForLevel(LogLevel.Trace);
                rule.DisableLoggingForLevel(LogLevel.Debug);
            }
            LogManager.ReconfigExistingLoggers();

            Logger.Trace("TRACE 2");
            Logger.Debug("DEBUG 2");
            Logger.Warn("WARN 2");

            // Reconfigure();
            LogManager.Configuration = LogManager.Configuration.Reload();
            LogManager.ReconfigExistingLoggers();

            Logger.Trace("TRACE 3");
            Logger.Debug("DEBUG 3");
            Logger.Warn("WARN 3");
        }

output:

(DEBUG): DEBUG 1
(WARN): WARN 1
// here settings changed
(WARN): WARN 2
//here settings reloaded
(DEBUG): DEBUG 3
(WARN): WARN 3

Best Answer

Related Solutions

C# – How to log System.Diagnostics.Trace and System.Diagnostics.Debug messages to NLog file

C# – How to force reload of NLog configuration file

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