MDC missing from graylog

Question

I have the following test. I add something to the context map and the context stack, and then write a message. The message goes into graylog, but there is nothing about the pushed message or the pushed key.

    @Test
public void test2() {
    try (CloseableThreadContext.Instance c = CloseableThreadContext.push("pushed message").put("pushed key", "pushed value")){
        LogManager.getLogger().warn("warn level message seeing if it goes into graylog.");
    }
}

I used both of these configurations, and neither one worked.

Attempt 1:

       <Gelf name="gelf" host="udp:localhost" port="12201" version="1.1" extractStackTrace="true"
          filterStackTrace="true" mdcProfiling="true" includeFullMdc="true" maximumMessageSize="8192"
          originHost="%host{fqdn}">
        <Field name="class" pattern="%c"/>
        <Field name="classname" pattern="%c{1}"/>
        <Field name="exception" pattern="%ex{full}"/>
        <Field name="method" pattern="%method"/>
        <Field name="line" pattern="%line"/>
        <Field name="application_name" pattern="${application}"/>
        <Field name="sequenceNumber" pattern="%sequenceNumber"/>
        <Field name="application_version" pattern="${application.version}"/>
        <Field name="marker" pattern="%marker"/>
        <Field name="thread" pattern="%thread"/>
        <Field name="system_nano_time" pattern="%nano"/>
        <Field name="app_uptime" pattern="%relative"/>
        <Field name="severity" pattern="%level{WARN=Warning, DEBUG=Debug, ERROR=Error, TRACE=Trace, INFO=Info}"/>
    </Gelf>

Attempt 2:

        <Gelf name="gelf" host="udp:localhost" port="12201" version="1.1" extractStackTrace="true"
              filterStackTrace="true" mdcProfiling="true" includeFullMdc="true" maximumMessageSize="8192"
              originHost="%host{fqdn}">
            <Field name="timestamp" pattern="%d{dd MMM yyyy HH:mm:ss,SSS}" />
            <Field name="level" pattern="%level" />
            <Field name="simpleClassName" pattern="%C{1}" />
            <Field name="className" pattern="%C" />
            <Field name="server" pattern="%host" />
            <Field name="server.fqdn" pattern="%host{fqdn}" />
             

            <DynamicMdcFields regex="mdc.*" />
            <Field name="mdcField2" mdc="mdcField2" /> 
            <DynamicMdcFields regex="(mdc|MDC)fields" />
            <DynamicMdcFieldType regex="my_field.*" type="String" />
        </Gelf>

I looked here How to transfer MDC via gelf to graylog? and that didn't work - the messages showed up in graylog without the MDC.

I am using the following dependency:

        <dependency>
            <groupId>biz.paluch.logging</groupId>
            <artifactId>logstash-gelf</artifactId>
            <version>1.15.0</version>
        </dependency>

score 0 · Answer 1 · answered Sep 13 '22 at 18:58

Adding these lines to the log4j2 configuration added the context stack and the context map as fields, which was a big improvement. I also figured out that if you try to use the automatic mdc mapping if your mdc key has a space in it (possibly other characters as well, not sure) the field is silently dropped by the graylog server. I ran the program in the debugger and saw that the fields do get sent on the socket, but they never show up on the graylog server.

<Field name="context_stack" pattern="%x"/>
<Field name="context_map" pattern="%X"/>

MDC missing from graylog

1 Answers1