Styjun

I'm new to NLog, and fighting with finding the solution to what I'm going for.

I'd like warning and up to get pushed to a slack channel with log level specific icons. I have got that working, technically. I have 2 pairs of targets/loggers that are hard coded to catch warnings only, and errors and above, and have 'warning' or 'error' icons hard coded into the layout template.

<target xsi:type="WebService"
 name="slackWarningTarget"
 url="https://hooks.slack.com/services/xx/xx/xx"
 protocol="JsonPost"
 encoding="utf-8"
 >

 <parameter name="text" type="System.String" layout=":warning: $machinename $message"/>
 <parameter name="channel" type="System.String" layout="xx"/>
</target>

and

<logger name="*" minlevel="Warn" maxlevel="Warn" writeTo="slackWarningTarget">

Is there a way to better accomplish this? I want warning level to map to :warning:, etc.

I'd also like some info level stuff pushed there as well. To do this I created a named logger that always logs to the slack channel, but it results in duplicated messages if they are warning or above.

<logger name="noticeLogger" writeTo="slackInfoTarget" />

I'd guess there is a much more elegant way to do both of these things than i have come up with on my own.

You could do that from config with a $when, e.g.

layout="$when:when=$level=='Warn':inner=:warning::else:$when:when=$level== 'Error':inner=:error::else:todo"

but it get clumsy fast.

Another option is to register a custom layout renderer:

// register in the start of your program (e.g. main, app_start)
// usage $slackIcon
LayoutRenderer.Register("slackIcon", logEvent =>

 if (logEvent.Level == LogLevel.Warn)
 
 return ":warning:";
 
 if (logEvent.Level == LogLevel.Error)
 
 return ":error:";
 

 return ":other:";
 //etc
);

See How to write a custom layout renderer