Logging with log4j on tomcat jruby-rack for a Rails 3 application
- by John
I just spent the better part of 3 hours trying to get my Rails application logging with Log4j. I've finally got it working, but I'm not sure if what I did is correct. I tried various methods to no avail until my various last attempt. So I'm really looking for some validation here, perhaps some pointers and tips as well -- anything would be appreciated to be honest. I've summarized all my feeble methods into three attempts below. I'm hoping for some enlightenment on where I went wrong with each attempt -- even if it means I get ripped up.
Thanks for the help in advance!
System Specs
Rails 3.0
Windows Server 2008
Log4j 1.2
Tomact 6.0.29
Java 6
Attempt 1 - Configured Tomcat to Use Log4J
I basically followed the guide on the Apache Tomcat website here. The steps are:
Create a log4j.properties file in $CATALINA_HOME/lib
Download and copy the log4j-x.y.z.jar into $CATALINA_HOME/lib
Replace $CATALINA_HOME/bin/tomcat-juli.jar with the tomcat-juli.jar from the Apache Tomcat Extras folder
Copy tomcat-juli-adapters.jar from the Apache Tomcat Extras folder into $CATALINA_HOME/lib
Delete $CATALINA_BASE/conf/logging.properties
Start Tomcat (as a service)
Expected Results According to the Guide
I should have seen a tomcat.log file in my $CATALINA_BASE/logs folder.
Actual Results
No tomcat.log
Saw three of the standard logs instead
jakarta_service_20101231.log
stderr_20101231.log
stdout_20101231.log
Question
Shouldn't I have at least seen a tomcat.log file?
Attempt 2 - Use default Tomcat logging (commons-logging)
Reverted all the changes from the previous setup
Modified $CATALINA_BASE/conf/logging.properties by doing the following:
Adding a setting for my application in the handlers line: 5rails3.org.apache.juli.FileHandler
Adding Handler specific properties
5rails3.org.apache.juli.FileHandler.level = FINE
5rails3.org.apache.juli.FileHandler.directory = ${catalina.base}/logs
5rails3.org.apache.juli.FileHandler.prefix = rails3.
Adding Facility specific properties
org.apache.catalina.core.ContainerBase.[Catalina].[localhost].[/rails3].level = INFO
org.apache.catalina.core.ContainerBase.[Catalina].[localhost].[/rails3].handlers = 4host-manager.org.apache.juli.FileHandler
Modified my web.xml by adding the following context parameter as per the Logging section of the jruby-rack readme (I also modified my warbler.rb accordingly, but I did opted to change the web.xml directly to test things faster).
<context-param>
<param-name>jruby.rack.logging</param-name>
<param-value>commons_logging</param-value>
</context-param>
Restarted Tomcat
Results
A log file was created (rails3.log), however there was no log information in the file.
Attempt 2A - Use Log4j with existing set up
I decided to go Log4j another whirl with this new web.xml setting.
Copied the log4j.jar into my WEB-INF/lib folder
Created a log4j.properties file and put it into WEB-INF/classes
log4j.rootLogger=INFO, R
log4j.logger.javax.servlet=DEBUG
log4j.appender.R=org.apache.log4j.RollingFileAppender
log4j.appender.R.File=${catalina.base}/logs/rails3.log
log4j.appender.R.MaxFileSize=5036KB
log4j.appender.R.MaxBackupIndex=4
log4j.appender.R.layout=org.apache.log4j.PatternLayout
log4j.appender.R.layout.ConversionPattern=%d{dd MMM yyyy HH:mm:ss} [%t] %-5p %c %x - %m%n
Restarted Tomcat
Results
Same as Attempt 2
NOTE: I used log4j.logger.javax.servlet=DEBUG because I read in the jruby-rack README that all logging output is automatically redirected to the javax.servlet.ServletContext#log method. So I though this would capture it. I was obviously wrong.
Question
Why didn't this work?
Isn't Log4J using the commons_logging API?
Attempt 3 - Tried out slf4j (WORKED)
A bit uncertain as to why Attempt 2A didn't work, I thought to myself, maybe I can't use commons_logging for the jruby.rack.logging parameter because it's probably not using commons_logging API... (but I was still not sure). I saw slf4j as an option. I have never heard of it and by stroke of luck, I decided to look up what it is. After reading briefly about what it does, I thought it was good of a shot as any and decided to try it out following the instructions here.
Continuing from the setup of Attempt 2A:
Copied slf4j-api-1.6.1.jar and slf4j-simple-1.6.1.jar into my WEB-INF/lib folder
I also copied slf4j-log4j12-1.6.1.jar into my WEB-INF/lib folder
Restarted Tomcat
And VIOLA! I now have logging information going into my rails3.log file.
So the big question is:
WTF?
Even though logging seems to be working now, I'm really not sure if I did this right. So like I said earlier, I'm really looking for some validation more or less. I'd also appreciate any pointers/tips/advice if you have any. Thanks!
