Configuring Solr 1.4 logging with Log4J in Tomcat

Solr 1.4 logging is based on the “SLF4J” API. To configure Solr to use Log4J as standard logging implementation deploy the Solr web application to your Tomcat. Once the Solr web application got started add the libraries “slf4j-log4j12-1.5.5.jar” and “log4j-1.2.15.jar” to $CATALINA_HOME/webapps/solr/WEB-INF/lib. Delete the library “slf4j-jdk14-1.5.5.jar” from $CATALINA_HOME/webapps/solr/WEB-INF/lib.

Create the directory $CATALINA_HOME/webapps/solr/WEB-INF/classes and add the file log4j.properties. The file should hold your Log4J configuration. Here’s an example using a rolling log file:

1log4j.rootLogger=ERROR, logfile

2 

3log4j.appender.logfile=org.apache.log4j.DailyRollingFileAppender

4log4j.appender.logfile.File=${catalina.home}/logs/solr.log

5 

6log4j.appender.logfile.DatePattern='.'yyyy-MM-dd

7log4j.appender.logfile.layout=org.apache.log4j.PatternLayout

8

log4j.appender.logfile.layout.ConversionPattern=%d %p [%c{3}] - [%t] - %X{ip}: %m%n

 

Alternatively, you can prepare your Solr web application WAR file to reflect the steps mentioned above. The Solr logging page (http://<host>:<port>/solr/admin/logging) that comes with the web app will not reflect these changes. It only works for JDK logging that we just configured not to be used anymore. The Tomcat instance has to be restarted to reflect the changes.