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Logging in JBoss Web

Important note

By default, only java.util.logging is available for the core JBoss Web, as JBoss Web uses a package renamed logging implementation which is hardcoded for that logger. Usage of alternate loggers is available after building the extra components (see the extras components documentation), which includes a full commons-logging implementation.

Introduction

JBoss Web uses JBoss Logging throughout its internal code. JBoss Logging provides JBoss Web the ability to log hierarchially across various log levels without needing to rely on a particular logging implementation.

An important consequence for JBoss Web is that the <Logger> element found in versions of Tomcat prior to 6.0 to create a localhost_log is no longer a valid nested element of <Context>. Instead, the default JBoss Web configuration will use java.util.logging. If the developer wishes to collect detailed internal JBoss Web logging (i.e what is happening within the JBoss Web engine), then they should configure a logging system such as java.util.logging or log4j as detailed next.

java.util.logging

The default implemenatation of java.util.logging provided in the JDK is too limited to be useful. A limitation of JDK Logging appears to be the inability to have per-web application logging, as the configuration is per-VM. As a result, JBoss Web will, in the default configuration, replace the default LogManager implementation with a container friendly implementation called JULI, which addresses these shortcomings. It supports the same configuration mechanisms as the standard JDK java.util.logging, using either a programmatic approach, or properties files. The main difference is that per-classloader properties files can be set (which enables easy redeployment friendly webapp configuration), and the properties files support slightly extended constructs which allows more freedom for defining handlers and assigning them to loggers.

JULI is enabled by default in JBoss Web, and supports per classloader configuration, in addition to the regular global java.util.logging configuration. This means that logging can be configured at the following layers:

  • In the JDK's logging.properties file. Check your JAVA_HOME environment setting to see which JDK JBoss Web is using. The file will be in $JAVA_HOME/jre/lib. Alternately, it can also use a global configuration file located elsewhere by using the system property java.util.logging.config.file, or programmatic configuration using java.util.logging.config.class.
  • In each classloader using a logging.properties file. This means that it is possible to have a configuration for the JBoss Web core, as well as separate configurations for each webapps which will have the same lifecycle as the webapps.

The default logging.properties specifies a ConsoleHandler for routing logging to stdout and also a FileHandler. A handler's log level threshold can be set using SEVERE, WARNING, INFO, CONFIG, FINE, FINER, FINEST or ALL. The logging.properties shipped with JDK is set to INFO. You can also target specific packages to collect logging from and specify a level. Here is how you would set debugging from JBoss Web. You would need to ensure the ConsoleHandler's level is also set to collect this threshold, so FINEST or ALL should be set. Please refer to Sun's java.util.logging documentation for the complete details. 

org.apache.catalina.level=FINEST

The configuration used by JULI is extremely similar, but uses a few extensions to allow better flexibility in assigning loggers. The main differences are:

  • A prefix may be added to handler names, so that multiple handlers of a single class may be instantiated. A prefix is a String which starts with a digit, and ends with '.'. For example, 22foobar. is a valid prefix.
  • As in Java 5.0, loggers can define a list of handlers using the loggerName.handlers property.
  • By default, loggers will not delegate to their parent if they have associated handlers. This may be changed per logger using the loggerName.useParentHandlers property, which accepts a boolean value.
  • The root logger can define its set of handlers using a .handlers property.
  • System property replacement for property values which start with ${sytstemPropertyName}.

Example logging.properties file to be placed in common/classes: 

handlers = 1catalina.org.apache.juli.FileHandler, 2localhost.org.apache.juli.FileHandler, \
           3manager.org.apache.juli.FileHandler, 4admin.org.apache.juli.FileHandler, \
           java.util.logging.ConsoleHandler

.handlers = 1catalina.org.apache.juli.FileHandler, java.util.logging.ConsoleHandler

############################################################
# Handler specific properties.
# Describes specific configuration info for Handlers.
############################################################

1catalina.org.apache.juli.FileHandler.level = FINE
1catalina.org.apache.juli.FileHandler.directory = ${catalina.base}/logs
1catalina.org.apache.juli.FileHandler.prefix = catalina.

2localhost.org.apache.juli.FileHandler.level = FINE
2localhost.org.apache.juli.FileHandler.directory = ${catalina.base}/logs
2localhost.org.apache.juli.FileHandler.prefix = localhost.

3manager.org.apache.juli.FileHandler.level = FINE
3manager.org.apache.juli.FileHandler.directory = ${catalina.base}/logs
3manager.org.apache.juli.FileHandler.prefix = manager.

4admin.org.apache.juli.FileHandler.level = FINE
4admin.org.apache.juli.FileHandler.directory = ${catalina.base}/logs
4admin.org.apache.juli.FileHandler.prefix = admin.

java.util.logging.ConsoleHandler.level = FINE
java.util.logging.ConsoleHandler.formatter = java.util.logging.SimpleFormatter


############################################################
# Facility specific properties.
# Provides extra control for each logger.
############################################################

org.apache.catalina.core.ContainerBase.[Catalina].[localhost].level = INFO
org.apache.catalina.core.ContainerBase.[Catalina].[localhost].handlers = \
   2localhost.org.apache.juli.FileHandler

org.apache.catalina.core.ContainerBase.[Catalina].[localhost].[/manager].level = INFO
org.apache.catalina.core.ContainerBase.[Catalina].[localhost].[/manager].handlers = \
   3manager.org.apache.juli.FileHandler

org.apache.catalina.core.ContainerBase.[Catalina].[localhost].[/admin].level = INFO
org.apache.catalina.core.ContainerBase.[Catalina].[localhost].[/admin].handlers = \
   4admin.org.apache.juli.FileHandler

# For example, set the com.xyz.foo logger to only log SEVERE
# messages:
#org.apache.catalina.startup.ContextConfig.level = FINE
#org.apache.catalina.startup.HostConfig.level = FINE
#org.apache.catalina.session.ManagerBase.level = FINE

Example logging.properties for the servlet-examples web application to be placed in WEB-INF/classes inside the web application: 

handlers = org.apache.juli.FileHandler, java.util.logging.ConsoleHandler

############################################################
# Handler specific properties.
# Describes specific configuration info for Handlers.
############################################################

org.apache.juli.FileHandler.level = FINE
org.apache.juli.FileHandler.directory = ${catalina.base}/logs
org.apache.juli.FileHandler.prefix = servlet-examples.

java.util.logging.ConsoleHandler.level = FINE
java.util.logging.ConsoleHandler.formatter = java.util.logging.SimpleFormatter

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