java - Configuring RollingFileAppender in log4j

Question

I'm working on a set of web services and we'd like to have a daily rotated log.

I'm trying to get org.apache.log4j.rolling.RollingFileAppender from the log4j extras companion working, since the documentation suggests this is best for production environments.

I have both the main log4J library (log4j-1.2.15.jar) and the log4j extras library (apache-log4j-extras-1.1.jar) on the classpath.

I have the following configuration for the appender in the log4j.properties file:

### SOAP Request Appender
log4j.appender.request=org.apache.log4j.rolling.RollingFileAppender
log4j.appender.request.File=SOAPmessages.log
log4j.appender.request.RollingPolicy=org.apache.log4j.rolling.TimeBasedRollingPolicy
log4j.appender.request.RollingPolicy.ActiveFileName =SOAPmessages-%d.log
log4j.appender.request.RollingPolicy.FileNamePattern=SOAPmessages-%d.log.zip
log4j.appender.request.layout = org.apache.log4j.PatternLayout
log4j.appender.request.layout.ConversionPattern=%d{ABSOLUTE} %5p %c{1}:%L - %m%n

However, when I start the web service with log4j in debug mode I get these error messages:

log4j: Parsing appender named "request".
log4j: Parsing layout options for "request".
log4j: Setting property [conversionPattern] to [%d{ABSOLUTE} %5p %c{1}:%L - %m%n].
log4j: End of parsing for "request".
log4j: Setting property [file] to [/logs/SOAPmessages.log].
log4j:WARN Failed to set property [rollingPolicy] to value "org.apache.log4j.rolling.TimeBasedRollingPolicy". 
log4j:WARN Please set a rolling policy for the RollingFileAppender named 'request'
log4j: Parsed "request" options.

I've found documentation about how to configure this appender a little sparse, so can anyone help me fix my configuration?

EDIT0: Added debug mode output, rather than just the standard warnings

Answer 1

I had a similar problem and just found a way to solve it (by single-stepping through log4j-extras source, no less...)

The good news is that, unlike what's written everywhere, it turns out that you actually CAN configure TimeBasedRollingPolicy using log4j.properties (XML config not needed! At least in versions of log4j >1.2.16 see this bug report)

Here is an example:

log4j.appender.File = org.apache.log4j.rolling.RollingFileAppender
log4j.appender.File.rollingPolicy = org.apache.log4j.rolling.TimeBasedRollingPolicy
log4j.appender.File.rollingPolicy.FileNamePattern = logs/worker-${instanceId}.%d{yyyyMMdd-HHmm}.log

BTW the ${instanceId} bit is something I am using on Amazon's EC2 to distinguish the logs from all my workers -- I just need to set that property before calling PropertyConfigurator.configure(), as follow:

p.setProperty("instanceId", EC2Util.getMyInstanceId());
PropertyConfigurator.configure(p);