Getting Data In

What log4j ConversionPattern should I use to match splunk log4j sourcetype?

twhitbeck
Engager

I have a webapp running in Tomcat. I'm using Log4j for my logging, and whenever I load the .log file in Splunk it is not able to determine it's sourcetype. It properly extracts the timestamp, but the rest of the log event is lumped together under the field "event". I want to extract the fields that are in my log (thread, priority, message).

According to Splunk documentation there is a log4j pretrained sourcetype. The log should be of the format: 2005-03-07 16:44:03,110 53223013 [PoolThread-0] INFO [STDOUT] got some property... Well I'm using a log4j ConversionPattern of %d %r [%t] %-5p [STDOUT] %m%n and it's producing log output like: 2012-12-21 09:51:00,937 81 [localhost-startStop-1] INFO [STDOUT] Quartz Scheduler v.1.7.3 created. which looks very similar to the log4j layout prescribed in the Splunk docs, but Splunk is still not recognizing the sourcetype and extracting the fields.

I know I can define my own sourcetype and configure the fields to be extracted with regular expressions, but I didn't want to go through all the hassle if Splunk has already done the work for me.

What log4j conversionpattern should I be using so that Splunk will recognize it as a log4j sourcetype and extract the proper fields?

Tags (3)

emiller42
Motivator

If you've got control over your log4j configuration, you can bypass the field extraction entirely by using explicit key/value pairs.

%d{ISO8601} logLevel=%p thread=\"%t\" category=%c %m%n

would output:

2012-12-21 09:51:00,937 logLevel=INFO thread="localhost-startStop-1" category=STDOUT Quartz Scheduler v.1.7.3 created.

Splunk will automatically detect the key/value pairs in the above. If your app uses the MDC with log4J, you can easily add more context this way.

thefosk
Engager

+1, I'm facing the same issue

0 Karma
Got questions? Get answers!

Join the Splunk Community Slack to learn, troubleshoot, and make connections with fellow Splunk practitioners in real time!

Meet up IRL or virtually!

Join Splunk User Groups to connect and learn in-person by region or remotely by topic or industry.

Get Updates on the Splunk Community!

May 2026 Splunk Expert Sessions: Security & Observability

Level Up Your Operations: May 2026 Splunk Expert Sessions Whether you are refining your security posture or ...

Network to App: Observability Unlocked [May & June Series]

In today’s digital landscape, your environment is no longer confined to the data center. It spans complex ...

SPL2 Deep Dives, AppDynamics Integrations, SAML Made Simple and Much More on Splunk ...

Splunk Lantern is Splunk’s customer success center that provides practical guidance from Splunk experts on key ...