Example 10.1. Assigning categories to specific appenders

  <appender name="App1Log" class="org.apache.log4j.FileAppender">
      <errorHandler  
             class="org.jboss.logging.util.OnlyOnceErrorHandler"/>
      <param name="Append" value="false"/>
      <param name="File" 
             value="${jboss.server.home.dir}/log/app1.log"/>
      <layout class="org.apache.log4j.PatternLayout">
         <param name="ConversionPattern" 
                value="%d{ABSOLUTE} %-5p [%c{1}] %m%n"/>
      </layout>
   </appender>

...

   <category name="com.app1">
     <appender-ref ref="App1Log"/>
   </category>
   <category name="com.util">
     <appender-ref ref="App1Log"/>
   </category>

...

   <root>
      <appender-ref ref="CONSOLE"/>
      <appender-ref ref="FILE"/>
      <appender-ref ref="App1Log"/>
   </root>

Example 10.2. Filtering log messages

   <appender name="App1Log" class="org.apache.log4j.FileAppender">
      <errorHandler 
           class="org.jboss.logging.util.OnlyOnceErrorHandler"/>
      <param name="Append" value="false"/>
      <param name="File" 
             value="${jboss.server.home.dir}/log/app1.log"/>
      <layout class="org.apache.log4j.PatternLayout">
         <param name="ConversionPattern" 
                value="%d{ABSOLUTE} %-5p [%c{1}] %m%n"/>
      </layout>
      <filter class="org.jboss.logging.filter.TCLFilter">
         <param name="AcceptOnMatch" value="true"/>
         <param name="DeployURL" value="app1.ear"/>
      </filter>
   </appender>

...

   <root>
      <appender-ref ref="CONSOLE"/>
      <appender-ref ref="FILE"/>
      <appender-ref ref="App1Log"/>
   </root>

Example 10.3. Setting up and using the Log4jSocketServer service.

The org.jboss.logging.Log4jSocketServer is an mbean service that allows one to collect output from multiple log4j clients (including jboss servers) that are using the org.apache.log4j.net.SocketAppender.

The Log4jSocketServer creates a server socket to accept SocketAppender connections, and logs incoming messages based on the local log4j.xml configuration.

You can create a minimal jboss configuration that includes a Log4jSocketServer to act as your log server.

Example 10.4. An Log4jSocketServer mbean configuration

The following MBean Configuration can be added to the conf/jboss-service.xml

   <mbean code="org.jboss.logging.Log4jSocketServer"
      name="jboss.system:type=Log4jService,service=SocketServer">
      <attribute name="Port">12345</attribute>
      <attribute name="BindAddress">${jboss.bind.address}</attribute>
   </mbean>

Example 10.5. Augmenting the log server console output with the logging client socket hostname

      <appender name="CONSOLE" class="org.apache.log4j.ConsoleAppender">
      <errorHandler class="org.jboss.logging.util.OnlyOnceErrorHandler"/>
      <param name="Target" value="System.out"/>
      <param name="Threshold" value="INFO"/>

      <layout class="org.apache.log4j.PatternLayout">
         <param name="ConversionPattern" value="%d{ABSOLUTE} %-5p [%c{1},%X{host}] %m%n"/>
      </layout>
   </appender>

Example 10.6. log4j.xml appender for the Log4jSocketServer

   <appender name="SOCKET" class="org.apache.log4j.net.SocketAppender">
      <param name="Port" value="12345"/>
      <param name="RemoteHost" value="loghost"/>
      <param name="ReconnectionDelay" value="60000"/>
      <param name="Threshold" value="INFO"/>
   </appender>

Example 10.7. Adding an appender-ref to a category

   <appender name="JSR77" class="org.apache.log4j.FileAppender">
      <param name="File"
             value="${jboss.server.home.dir}/log/jsr77.log"/>
...
   </appender>

   <!-- Limit the JSR77 categories -->
   <category name="org.jboss.management" additivity="false">
      <priority value="DEBUG"/>
      <appender-ref ref="JSR77"/>
   </category>

This sends allorg.jboss.management output to the jsr77.log file. The additivity attribute controls whether output continues to go to the root category appender. If false, output only goes to the appenders referred to by the category.

Example 10.8. Sample log4j.properties

# Debug log4j
log4j.debug=true  
log4j.rootLogger=debug, myapp

log4j.appender.myapp=org.apache.log4j.FileAppender
log4j.appender.myapp.layout=org.apache.log4j.HTMLLayout
log4j.appender.myapp.layout.LocationInfo=true
log4j.appender.myapp.layout.Title='All' Log
log4j.appender.myapp.File=${jboss.server.home.dir}/deploy/myapp.war/WEB-INF/logs/myapp.html
log4j.appender.myapp.ImmediateFlush=true
log4j.appender.myapp.Append=false

Example 10.9. A RepositorySelector

The following code shows a RepositorySelector that looks for a log4j.xml file in the WEB-INF directory.

 
 /*
  * JBoss, Home of Professional Open Source
  * Copyright 2005, JBoss Inc., and individual contributors as indicated
  * by the @authors tag. See the copyright.txt in the distribution for a
  * full listing of individual contributors.
  *
  * This is free software; you can redistribute it and/or modify it
  * under the terms of the GNU Lesser General Public License as
  * published by the Free Software Foundation; either version 2.1 of
  * the License, or (at your option) any later version.
  *
  * This software is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  * Lesser General Public License for more details.
  *
  * You should have received a copy of the GNU Lesser General Public
  * License along with this software; if not, write to the Free
  * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
  * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
  */
package org.jboss.repositoryselectorexample;

import java.io.InputStream;
import java.util.HashMap;
import java.util.Map;
import javax.servlet.ServletConfig;
import javax.servlet.ServletException;
import javax.xml.parsers.DocumentBuilderFactory;
import org.apache.log4j.Hierarchy;
import org.apache.log4j.Level;
import org.apache.log4j.LogManager;
import org.apache.log4j.spi.LoggerRepository;
import org.apache.log4j.spi.RepositorySelector;
import org.apache.log4j.spi.RootCategory;
import org.apache.log4j.xml.DOMConfigurator;
import org.w3c.dom.Document;

/**
 * This RepositorySelector is for use with web applications.  
 * It assumes that your log4j.xml file is in the WEB-INF directory.
 * @author  Stan Silvert
 */
public class MyRepositorySelector implements RepositorySelector
{
   private static boolean initialized = false;

   // This object is used for the guard because it doesn't get
   // recycled when the application is redeployed.
   private static Object guard = LogManager.getRootLogger();
   
   private static Map repositories = new HashMap();
   private static LoggerRepository defaultRepository;

   /**
    * Register your web-app with this repository selector.
    */
   public static synchronized void init(ServletConfig config) 
        throws ServletException {
      if( !initialized ) // set the global RepositorySelector
      {
         defaultRepository = LogManager.getLoggerRepository();
         RepositorySelector theSelector = new MyRepositorySelector();
         LogManager.setRepositorySelector(theSelector, guard);
         initialized = true;
      }
      
      Hierarchy hierarchy = new Hierarchy(new
                                RootCategory(Level.DEBUG));
      loadLog4JConfig(config, hierarchy);
      ClassLoader loader = 
           Thread.currentThread().getContextClassLoader();
      repositories.put(loader, hierarchy);
   }

   // load log4j.xml from WEB-INF
   private static void loadLog4JConfig(ServletConfig config, 
                                       Hierarchy hierarchy) 
                                            throws ServletException {
        try {
            String log4jFile = "/WEB-INF/log4j.xml";
            InputStream log4JConfig = 
                
            config.getServletContext().getResourceAsStream(log4jFile);
            Document doc = DocumentBuilderFactory.newInstance()
                                                 .newDocumentBuilder()
                                                 .parse(log4JConfig);
            DOMConfigurator conf = new DOMConfigurator();
            conf.doConfigure(doc.getDocumentElement(), hierarchy);
        } catch (Exception e) {
            throw new ServletException(e);
        }
    }

   private MyRepositorySelector() {
   }

   public LoggerRepository getLoggerRepository() {
      ClassLoader loader = 
             Thread.currentThread().getContextClassLoader();
      LoggerRepository repository = 
            (LoggerRepository)repositories.get(loader);
      
      if (repository == null) {
          return defaultRepository;
      } else {
          return repository;
      }
   }
}