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Posted to dev@tomcat.apache.org by Apache Wiki <wi...@apache.org> on 2010/03/28 03:05:52 UTC

[Tomcat Wiki] Update of "FAQ/Logging" by KonstantinKolinko

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The "FAQ/Logging" page has been changed by KonstantinKolinko.
The comment on this change is: Updated.
http://wiki.apache.org/tomcat/FAQ/Logging?action=diff&rev1=15&rev2=16

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  The Servlet Specification requires Servlet Containers like Tomcat to provide at least a rudimentary implementation of the {{{ServletContext#log}}} method. Tomcat provides a much richer implementation than required by the Spec, as follows:
  
-  * Prior to Tomcat 5.5, Tomcat provided a Logger element that you could configure and extend according to your needs. If you are using a Tomcat version previous to Tomcat 5.5, make sure to read the [[http://tomcat.apache.org/tomcat-4.1-doc/config/logger.html|Logger configuration reference]].
+  * Prior to Tomcat 5.5, Tomcat provided a Logger element that you could configure and extend according to your needs.
-  * Starting with Tomcat 5.5, Logger was removed and [[http://jakarta.apache.org/commons/logging|Jakarta Commons-Logging]] {{{Log}}} is used everywhere in Tomcat. Read the Commons-Logging documentation if you'd like to know how to better use and configure Tomcat's internal logging. See also http://tomcat.apache.org/tomcat-5.5-doc/logging.html
+  * Starting with Tomcat 5.5, Logger was removed and [[http://commons.apache.org/logging/|Apache Commons-Logging]] {{{Log}}} is used everywhere in Tomcat. Read the Commons-Logging documentation if you'd like to know how to better use and configure Tomcat's internal logging. See also http://tomcat.apache.org/tomcat-5.5-doc/logging.html
   * To enable request logging similar to the Apache HTTP server, you may include the following line in the server.xml file, in the <Engine> tag:
    . <Valve className="org.apache.catalina.valves.AccessLogValve"
     . directory="logs"  prefix="localhost_access_log." suffix=".log"
@@ -30, +30 @@

    . This will produce a log file for each day,  such as  logs/localhost_access_log.2008-03-10.log, containing the files requested, IP address of the requester, and similar information.
     . 128.34.123.121 - - [10/Mar/2008:15:55:57 -0500] "GET /upload/ClickPoints.jsp HTTP/1.1" 200 2725
  
- In addition, Tomcat does not swallow the System.out and System.err JVM output streams. You may use these streams for elementary logging if you wish, but a more robust approach such as commons-logging or [[http://logging.apache.org/log4j|Log4J]] is recommended for production applications.
+ In addition, Tomcat does not swallow the System.out and System.err JVM output streams. You may use these streams for elementary logging if you wish, but a more robust approach such as commons-logging or [[http://logging.apache.org/log4j/|Log4J]] is recommended for production applications.
  
  <<Anchor(Q2)>>'''What role does commons-logging play in logging?'''
  
  Tomcat wants to support multiple logging implementations, so it uses commons-logging. In case that's unclear, think of it like this.  You are a Tomcat developer.  The car you drive when logging is the commons-logging car.  The engine of that car is either JULI or log4j.  Without one of these engines, the car goes no where.  However regardless of whether you use JULI or log4j, the steering wheel, break, gas pedal, etc. are the same.
  
- Related FAQ: What role does JULI and log4j play in logging?
+ Related FAQ: [[#Q3|What role does JULI and log4j play in logging?]]
  
  <<Anchor(Q3)>>'''What role does JULI and log4j play in logging?'''
  
- First see: What role does commons-logging play in logging?
+ First see: [[#Q2|What role does commons-logging play in logging?]]
  
  Note in addition that in your own applications you could log directly with JULI or log4j.  But once you choose one, you can't easily switch to the other later.  If you use commons-logging you can.
  
  <<Anchor(Q4)>>'''How do I configure commons-logging for use with Tomcat?'''
  
- You need to specify a commons-logging configuration file and, if you wish, a logging implementation that supports commons-logging. JDK 1.4 (and later) java.util.Logging and Log4j are the two most commonly used logging toolkits for Tomcat. Tomcat 5.5 and Tomcat 6.0 use java.logging as default implementation for commons-logging. So this ''should'' work by default, but sometimes it doesn't (see [[#Q9]]). If you supply an external logging toolkit such as Log4J, it needs to be located in the $CATALINA_HOME/common/lib directory (for Tomcat 5.0 and earlier). Tomcat 5.5 and later uses commons-logging  while bootstrapping so some people suggest adding Log4j to the bootstrap classpath by using the scripts in $CATALINA_HOME/bin (see [[http://markmail.org/message/3sgxfol3njcfutsm|Need for it to be in bootstrap classpath?]]). A better approch apparently working is:
+ You need to specify a commons-logging configuration file and, if you wish, a logging implementation that supports commons-logging. JDK 1.4 (and later) java.util.Logging and Log4j are the two most commonly used logging toolkits for Tomcat. Tomcat 5.5 and Tomcat 6.0 use java.logging as default implementation for commons-logging. So this ''should'' work by default, but sometimes it doesn't (see [[#Q9]]).
+ 
+ If you supply an external logging toolkit such as Log4J, it needs to be located in the $CATALINA_HOME/common/lib directory (for Tomcat 5.0 and earlier). Tomcat 5.5 and later uses commons-logging while bootstrapping so some people suggest adding Log4j to the bootstrap classpath by using the scripts in $CATALINA_HOME/bin (see [[http://markmail.org/message/3sgxfol3njcfutsm|Need for it to be in bootstrap classpath?]]). A better approach apparently working is:
  
   1. Put log4j.jar in the $CATALINA_HOME/common/lib directory
   1. Put the ''full'' commons-logging.jar in the $CATALINA_HOME/common/lib directory, even if you see the ''reduced'' API version there, named commons-logging-api.jar
  
  Through some classloading voodoo during bootstrapping, if you have the full commons-logging.jar file in your common/lib directory, it replaces the classes from the commons-logging-api.jar file and will reinitialize the logging system and attempt to locate log4j or whatever other logging system you may be using. (see [[http://markmail.org/message/3sgxfol3njcfutsm#query:+page:1+mid:7oce37bngiq2otlu+state:results|this thread]]).
  
- For more detailed instructions, see these mailing list discussions:
+ The above recipe is for Tomcat 5.5. For Tomcat 6 - see [[http://tomcat.apache.org/tomcat-6.0-doc/logging.html|Documentation]].
+ 
+ See also the following mailing list discussions:
  
   * [[http://marc.theaimsgroup.com/?l=tomcat-user&m=106623436423859&w=2|A log4j example]]
   * [[http://marc.theaimsgroup.com/?l=tomcat-user&m=108330970225012&w=2|Logging Configuration]]
@@ -62, +66 @@

  
  <<Anchor(Q5)>>'''How should I log in my own webapps?'''
  
- While you can use System.out and System.err to log, we strongly recommend using a toolkit like Log4J or JDK 1.4's java.util.logging package. With these toolkits, you have significantly more functionality (for example, sending emails, logging to a database, controlling at runtime the logging level of different classes, inspecting the logs with a graphical viewer, etc.) than with Tomcat's built-in default logging configuration.
+ While you can use System.out and System.err to log, we strongly recommend using a toolkit like Log4J or JDK 1.4's java.util.logging package. With these toolkits, you have significantly more functionality. For example, sending emails, logging to a database, controlling at runtime the logging level of different classes, inspecting the logs with a graphical viewer, etc.
  
- We also recommend that you separate your logging from Tomcat's internal logging. That means you should bundle your logging toolkit with your webapp. If you're using Log4J, for example, place the Log4J jar in the WEB-INF/lib directory of your webapp and the Log4J configuration file in the WEB-INF/classes directory of your webapp. This way different web applications can have different logging configurations and you don't need to worry about them interfering with each other.
+ We also recommend that you separate your logging from Tomcat's internal logging. That means you should bundle your logging toolkit with your webapp. If you are using Log4J, for example, place the Log4J jar in the WEB-INF/lib directory of your webapp and the Log4J configuration file in the WEB-INF/classes directory of your webapp. This way different web applications can have different logging configurations and you don't need to worry about them interfering with each other.
  
  <<Anchor(Q6)>>'''Where does System.out go? How do I rotate catalina.out?'''
  
@@ -86, +90 @@

  
  For another example of how to set this look in catalina.sh for  Tomcat 6.0.16 on lines 182-185.  The statements look like this:
  
- # Set juli LogManager if it is present if [ -r "$CATALINA_BASE"/conf/logging.properties ]; then
- 
+ {{{
+ # Set juli LogManager if it is present
+ if [ -r "$CATALINA_BASE"/conf/logging.properties ]; then
-  . JAVA_OPTS="$JAVA_OPTS "-Djava.util.logging.manager=org.apache.juli.ClassLoaderLogManager" "-Djava.util.logging.config.file="$CATALINA_BASE/conf/    logging.properties"
+   JAVA_OPTS="$JAVA_OPTS "-Djava.util.logging.manager=org.apache.juli.ClassLoaderLogManager" "-Djava.util.logging.config.file="$CATALINA_BASE/conf/logging.properties"
- 
  fi
+ }}}
  
  Projects such as JPackage that repackage Tomcat for Linux typically move the configuration to a directory dictated by the FHS standard (http://www.pathname.com/fhs/), and therefore use the java.util.logging.config.file property to set the location of the logging.properties file in the Tomcat startup script.
  
@@ -103, +108 @@

  Here are some things you can check:
  
   1. tomcat-juli.jar should be in your $CATALINA_HOME/bin directory
-  1. tomcat startup script should run java with -Djava.util.logging.manager=org.apache.juli.ClassLoaderLogManager
+  1. tomcat startup script should run java with {{{-Djava.util.logging.manager=org.apache.juli.ClassLoaderLogManager}}}
-  1. tomcat startup script should run java with -Djava.util.logging.config.file=''<some_path>''/logging.properties
+  1. tomcat startup script should run java with {{{-Djava.util.logging.config.file=<some_path>/logging.properties}}}
   1. obviously, the logging.properties file must exist in the directory specified in the tomcat script at point #3
  
  If you don't know where to look for your Tomcat startup script, see the previous [[#Q8|How do I customize the location of the tomcat logging.properties file?]]
  
  In RHEL5 (RedHat Enterprise Server 5) the Tomcat 5.5 rpm installation does not include the tomcat-juli.jar file. This is what I made:
  
-  * look for what Tomcat version you got installed with: yum list installed tomcat5
+  * look for what Tomcat version you got installed with: {{{yum list installed tomcat5}}}
  
  Since I had the 5.5.23, I downloaded the Tomcat Binaries 5.5.23 from http://archive.apache.org/dist/tomcat/, then:
  

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