Providing a method name in the log4j2 GelfLayout

user_12474809 0
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I'm trying to include a calling method name as a separate field in the Gelf:

<Socket name="Graylog" protocol="udp" host="127.0.0.1" port="12201">
    <GelfLayout>
        <KeyValuePair key="method" value="%M"/>
    </GelfLayout>
</Socket>

But in the Graylog this field's value appears just as %M, no value substitution is happening.

I read the manual, but couldn't find anything about resolving message pattern placeholders in the custom fields.

I know that logstash-gelf can do this, but is it possible to do this without using an extra plugin, using the standard log4j2?

log4j2 java
1 Answers

I wanted to show what ID the thread had, but just as you, I noticed that the text was treated as static text. I looked into this and acording to the documentation it should be possible to use patterns, but not in <KeyValuePair>

  <GelfLayout includeThreadContext="true" threadContextIncludes="loginId,requestId">
    %d %5p [%t] %c{1} %X{loginId, requestId} - %m%n
    <KeyValuePair key="additionalField1" value="constant value"/>
    <KeyValuePair key="additionalField2" value="$${ctx:key}"/>
  </GelfLayout>

Look at the second row, above. It looks as if it would be possible to use pattern placeholders as a general message. I have, however, not been able to get this to work, maybe the version I use is to old.

I have found out that Log4j2 does not currently support what we want. But it will do in the next version (2.15.0). I have no idea, how ever, when the next version will be released, se issue LOG4J2-3041 for details.

References:

user_2481310
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