Why the LogLevel rule is not set for my NLog?

Question

I want to set the log level programmatically. But when I look up my logs, all logs are written (from Trace to Error). I code it like the example on stackoverflow.

foreach (var rule in NLog.LogManager.Configuration.LoggingRules)
{
    //rule.EnableLoggingForLevel(nlogLevel);
    rule.EnableLoggingForLevels(NLog.LogLevel.Warn, NLog.LogLevel.Fatal);
}
NLog.LogManager.ReconfigExistingLoggers();
Logger.LogTrace("LogLevel Trace");
Logger.LogDebug("LogLevel Debug");
Logger.LogInformation("LogLevel Info");
Logger.LogWarning("LogLevel Warn");
Logger.LogError("LogLevel Error");

I tried

rule.EnableLoggingForLevel(nlogLevel);

and

rule.EnableLoggingForLevels(NLog.LogLevel.Warn, NLog.LogLevel.Fatal);

Screen shot of the log's:

Why I can't change the log level?

That's interesting, because rule.DisableLoggingForLevel(NLog.LogLevel.Trace); works. It was just not the way I wanted to go, but a good workaround. — Frank Mehlhop, Jul 31 '19 at 13:47
@LorenzoIsidori Yes. But I thought whatever is written at my nlog.config I could set it programatically?! — Frank Mehlhop, Jul 31 '19 at 14:17
Of course you can but, at start, NLog load his config from file. if your config file has all level enabled, that will be your default...then you can go overriding levels. can you share your nlog.config? — Lorenzo Isidori, Jul 31 '19 at 14:30

score 2 · Answer 1 · answered Oct 01 '19 at 20:15

2

This also happened to me and I was able to solve it by running LogManager.ReconfigExistingLoggers(); after changing log levels.

answered Oct 01 '19 at 20:15

Juan Alvarez

307
2
5

score 2 · Answer 2 · answered Sep 21 '20 at 10:04

This will work for your case:

rule.SetLoggingLevels(NLog.LogLevel.Warn, NLog.LogLevel.Fatal);

From documentation:

Enables logging the levels between (included) minLevel and maxLevel. All the other levels will be disabled.

https://nlog-project.org/documentation/v4.5.0/html/M_NLog_Config_LoggingRule_SetLoggingLevels.htm

Julian · Accepted Answer · 2019-07-31T15:03:36.927

1

This is correct, enabling a loglevel doesn't mean disabling another.

Otherwise this will be an issue:

rule.EnableLoggingForLevel(LogLevel.Warn);
rule.EnableLoggingForLevel(LogLevel.Error); // luckily this won't disable Warn

What you could do:

Disable all loglevels first, and then enable the ones you need

rule.DisableLoggingForLevels(LogLevel.Trace, LogLevel.Fatal); // disable all
rule.EnableLoggingForLevels(NLog.LogLevel.Warn, NLog.LogLevel.Fatal); // enable needed

For this case - a minimum for all rules - there is also an easier way:

LogManager.GlobalThreshold = LogLevel.Info; // For all rules, minimum is Info

Please note that it's unclear why all the levels are enabled by default in your code. That's configured in the nlog.config or code, as that is not a default from NLog.

edited Jul 31 '19 at 15:03

answered Jul 31 '19 at 14:31

Julian

33,915
22
119
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You can just call `SetLoggingLevels()` instead of calling `DisableLoggingForLevels()` and `EnableLoggingForLevels()`. – ALittleDiff Sep 21 '20 at 09:58
You're right. `SetLoggingLevels()` has been added in NLog 4.5 – Julian Sep 21 '20 at 11:22

Why the LogLevel rule is not set for my NLog?

3 Answers3