| <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> |
| <!-- |
| Licensed to the Apache Software Foundation (ASF) under one or more |
| contributor license agreements. See the NOTICE file distributed with |
| this work for additional information regarding copyright ownership. |
| The ASF licenses this file to You under the Apache License, Version 2.0 |
| (the "License"); you may not use this file except in compliance with |
| the License. You may obtain a copy of the License at |
| |
| http://www.apache.org/licenses/LICENSE-2.0 |
| |
| Unless required by applicable law or agreed to in writing, software |
| distributed under the License is distributed on an "AS IS" BASIS, |
| WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| See the License for the specific language governing permissions and |
| limitations under the License. |
| --> |
| <!-- Generated by Apache Maven Doxia at Jul 29, 2014 --> |
| <html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en"> |
| <head> |
| <meta http-equiv="Content-Type" content="text/html; charset=UTF-8" /> |
| <title> |
| Logging Separation - Apache Log4j 2</title> |
| <link rel="stylesheet" href="../css/bootstrap.min.css" type="text/css" /> |
| <link rel="stylesheet" href="../css/site.css" type="text/css" /> |
| <script type="text/javascript" src="../js/jquery.min.js"></script> |
| <script type="text/javascript" src="../js/bootstrap.min.js"></script> |
| <script type="text/javascript" src="../js/prettify.min.js"></script> |
| <script type="text/javascript" src="../js/site.js"></script> |
| <meta name="author" content="Ralph Goers" /> |
| <meta name="Date-Revision-yyyymmdd" content="20140729" /> |
| <meta http-equiv="Content-Language" content="en" /> |
| |
| </head> |
| <body class="composite"> |
| <img class="logo-left" src="../images/ls-logo.jpg" alt="Apache logging services logo" /> |
| <img class="logo-right" src="../images/logo.jpg" alt="Apache log4j logo" /> |
| <div class="clear"></div> |
| |
| <div class="navbar"> |
| <div class="navbar-inner"> |
| <div class="container-fluid"> |
| <a class="brand" href="http://logging.apache.org/log4j/2.x/">Apache Log4j 2 ™</a> |
| <ul class="nav"> |
| <li> |
| |
| |
| <a href="http://wiki.apache.org/logging" class="external" target="_blank" title="Logging Wiki">Logging Wiki</a> |
| </li> |
| <li> |
| |
| |
| <a href="http://www.apache.org/" class="external" target="_blank" title="Apache">Apache</a> |
| </li> |
| <li> |
| <a href="../../../" title="Logging Services">Logging Services</a> |
| </li> |
| <li> |
| |
| |
| <a href="https://analysis.apache.org/dashboard/index/org.apache.logging.log4j:log4j" class="external" target="_blank" title="Sonar">Sonar</a> |
| </li> |
| </ul> |
| </div> |
| </div> |
| </div> |
| |
| <div class="container-fluid"> |
| <table class="layout-table"> |
| <tr> |
| <td class="sidebar"> |
| <div class="well sidebar-nav"> |
| <ul class="nav nav-list"> |
| <li class="nav-header"><i class="icon-home"></i>Apache Log4j™ 2</li> |
| <li class="none"> |
| <a href="../index.html" title="About">About</a> |
| </li> |
| <li class="none"> |
| <a href="../download.html" title="Download">Download</a> |
| </li> |
| <li class="none"> |
| <a href="../maven-artifacts.html" title="Maven and Ivy">Maven and Ivy</a> |
| </li> |
| <li class="none"> |
| <a href="../build.html" title="Build">Build</a> |
| </li> |
| <li class="none"> |
| <a href="../guidelines.html" title="Guidelines">Guidelines</a> |
| </li> |
| <li class="none"> |
| <a href="../javastyle.html" title="Style Guide">Style Guide</a> |
| </li> |
| <li class="none"> |
| <a href="../changelog.html" title="Changelog">Changelog</a> |
| </li> |
| <li class="collapsed"> |
| <a href="../javadoc.html" title="Javadoc">Javadoc</a> |
| </li> |
| <li class="none"> |
| <a href="../faq.html" title="FAQ">FAQ</a> |
| </li> |
| </ul> |
| <ul class="nav nav-list"> |
| <li class="nav-header"><i class="icon-book"></i>Manual</li> |
| <li class="none"> |
| <a href="../manual/index.html" title="Introduction">Introduction</a> |
| </li> |
| <li class="none"> |
| <a href="../manual/architecture.html" title="Architecture">Architecture</a> |
| </li> |
| <li class="none"> |
| <a href="../manual/migration.html" title="Log4j 1.x Migration">Log4j 1.x Migration</a> |
| </li> |
| <li class="collapsed"> |
| <a href="../manual/api.html" title="API">API</a> |
| </li> |
| <li class="collapsed"> |
| <a href="../manual/configuration.html" title="Configuration">Configuration</a> |
| </li> |
| <li class="collapsed"> |
| <a href="../manual/webapp.html" title="Web Applications and JSPs">Web Applications and JSPs</a> |
| </li> |
| <li class="collapsed"> |
| <a href="../manual/plugins.html" title="Plugins">Plugins</a> |
| </li> |
| <li class="collapsed"> |
| <a href="../manual/lookups.html" title="Lookups">Lookups</a> |
| </li> |
| <li class="collapsed"> |
| <a href="../manual/appenders.html" title="Appenders">Appenders</a> |
| </li> |
| <li class="collapsed"> |
| <a href="../manual/layouts.html" title="Layouts">Layouts</a> |
| </li> |
| <li class="collapsed"> |
| <a href="../manual/filters.html" title="Filters">Filters</a> |
| </li> |
| <li class="collapsed"> |
| <a href="../manual/async.html" title="Async Loggers">Async Loggers</a> |
| </li> |
| <li class="none"> |
| <a href="../manual/jmx.html" title="JMX">JMX</a> |
| </li> |
| <li class="none active"> |
| <a href="../manual/logsep.html" title="Logging Separation">Logging Separation</a> |
| </li> |
| <li class="collapsed"> |
| <a href="../manual/extending.html" title="Extending Log4j">Extending Log4j</a> |
| </li> |
| <li class="collapsed"> |
| <a href="../manual/customconfig.html" title="Extending Log4j Configuration">Extending Log4j Configuration</a> |
| </li> |
| <li class="collapsed"> |
| <a href="../manual/customloglevels.html" title="Custom Log Levels">Custom Log Levels</a> |
| </li> |
| </ul> |
| <ul class="nav nav-list"> |
| <li class="nav-header"><i class="icon-cog"></i>Components</li> |
| <li class="none"> |
| <a href="../log4j-api/index.html" title="API">API</a> |
| </li> |
| <li class="none"> |
| <a href="../log4j-core/index.html" title="Implementation">Implementation</a> |
| </li> |
| <li class="none"> |
| <a href="../log4j-jcl/index.html" title="Commons Logging Bridge">Commons Logging Bridge</a> |
| </li> |
| <li class="none"> |
| <a href="../log4j-1.2-api/index.html" title="Log4j 1.2 API">Log4j 1.2 API</a> |
| </li> |
| <li class="none"> |
| <a href="../log4j-slf4j-impl/index.html" title="SLF4J Binding">SLF4J Binding</a> |
| </li> |
| <li class="none"> |
| <a href="../log4j-to-slf4j/index.html" title="Log4j 2 to SLF4J Adapter">Log4j 2 to SLF4J Adapter</a> |
| </li> |
| <li class="none"> |
| <a href="../log4j-flume-ng/index.html" title="Apache Flume NG Appender">Apache Flume NG Appender</a> |
| </li> |
| <li class="none"> |
| <a href="../log4j-taglib/index.html" title="Log4j Tag Library">Log4j Tag Library</a> |
| </li> |
| <li class="none"> |
| <a href="../log4j-jmx-gui/index.html" title="Log4j JMX GUI">Log4j JMX GUI</a> |
| </li> |
| <li class="none"> |
| <a href="../log4j-web/index.html" title="Log4j Web Application Support">Log4j Web Application Support</a> |
| </li> |
| <li class="none"> |
| <a href="../log4j-nosql/index.html" title="Log4j NoSQL support">Log4j NoSQL support</a> |
| </li> |
| </ul> |
| <ul class="nav nav-list"> |
| <li class="nav-header"><i class="icon-info-sign"></i>Project Information</li> |
| <li class="none"> |
| <a href="../dependencies.html" title="Dependencies">Dependencies</a> |
| </li> |
| <li class="none"> |
| <a href="../dependency-convergence.html" title="Dependency Convergence">Dependency Convergence</a> |
| </li> |
| <li class="none"> |
| <a href="../dependency-management.html" title="Dependency Management">Dependency Management</a> |
| </li> |
| <li class="none"> |
| <a href="../team-list.html" title="Project Team">Project Team</a> |
| </li> |
| <li class="none"> |
| <a href="../mail-lists.html" title="Mailing Lists">Mailing Lists</a> |
| </li> |
| <li class="none"> |
| <a href="../issue-tracking.html" title="Issue Tracking">Issue Tracking</a> |
| </li> |
| <li class="none"> |
| <a href="../license.html" title="Project License">Project License</a> |
| </li> |
| <li class="none"> |
| <a href="../source-repository.html" title="Source Repository">Source Repository</a> |
| </li> |
| <li class="none"> |
| <a href="../project-summary.html" title="Project Summary">Project Summary</a> |
| </li> |
| </ul> |
| <ul class="nav nav-list"> |
| <li class="nav-header"><i class="icon-cog"></i>Project Reports</li> |
| <li class="none"> |
| <a href="../changes-report.html" title="Changes Report">Changes Report</a> |
| </li> |
| <li class="none"> |
| <a href="../jira-report.html" title="JIRA Report">JIRA Report</a> |
| </li> |
| <li class="none"> |
| <a href="../surefire-report.html" title="Surefire Report">Surefire Report</a> |
| </li> |
| <li class="none"> |
| <a href="../rat-report.html" title="RAT Report">RAT Report</a> |
| </li> |
| </ul> |
| </div> |
| <div id="poweredBy"> |
| <a href="http://maven.apache.org/" title="Built by Maven" class="poweredBy"> |
| <img class="poweredBy" alt="Built by Maven" src="../images/maven-feather.png" /> |
| </a> |
| </div> |
| </td> |
| <td class="content"> |
| <!-- Licensed to the Apache Software Foundation (ASF) under one or more |
| contributor license agreements. See the NOTICE file distributed with |
| this work for additional information regarding copyright ownership. |
| The ASF licenses this file to You under the Apache License, Version 2.0 |
| (the "License"); you may not use this file except in compliance with |
| the License. You may obtain a copy of the License at |
| |
| http://www.apache.org/licenses/LICENSE-2.0 |
| |
| Unless required by applicable law or agreed to in writing, software |
| distributed under the License is distributed on an "AS IS" BASIS, |
| WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| See the License for the specific language governing permissions and |
| limitations under the License. --> |
| |
| <div class="section"><h2>Logging Separation<a name="Logging_Separation"></a></h2> |
| <p> |
| There are many well known use cases where applications may share an environment with other applications |
| and each has a need to have its own, separate logging environment. This purpose of this section is to |
| discuss some of these cases and ways to accomplish this. |
| </p> |
| <div class="section"><h3>Use Cases<a name="Use_Cases"></a></h3> |
| <a name="Use_Cases"></a> |
| <p> |
| This section describes some of the use cases where Log4j could be used and what its desired behavior |
| might be. |
| </p> |
| <div class="section"><h4>Standalone Application<a name="Standalone_Application"></a></h4> |
| <p> |
| Standalone applications are usually relatively simple. They typically have one bundled executable |
| that requires only a single logging configuration. |
| </p> |
| </div><div class="section"><h4>Web Applications<a name="Web_Applications"></a></h4> |
| <p> |
| A typical web application will be packaged as a WAR file and will include all of its dependencies in |
| WEB-INF/lib and will have its configuration file located in the class path or in a location |
| configured in the web.xml. Be sure to follow the <a href="webapp.html">instructions to initialize Log4j 2 |
| in a web application</a>. |
| </p> |
| </div><div class="section"><h4>Java EE Applications<a name="Java_EE_Applications"></a></h4> |
| <p> |
| A Java EE application will consist of one or more WAR files and possible some EJBs, typically all |
| packaged in an EAR file. Usually, it is desirable to have a single configuration that applies to |
| all the components in the EAR. The logging classes will generally be placed in a location shared |
| across all the components and the configuration needs to also be shareable. Be sure to follow the |
| <a href="webapp.html">instructions to initialize Log4j 2 in a web application</a>. |
| </p> |
| </div><div class="section"><h4>"Shared" Web Applications and REST Service Containers<a name="aShared_Web_Applications_and_REST_Service_Containers"></a></h4> |
| <p> |
| In this scenario there are multiple WAR files deployed into a single container. Each of the applications |
| should use the same logging configuration and share the same logging implementation across each of the |
| web applications. When writing to files and streams each of the applications should share them to avoid |
| the issues that can occur when multiple components try to write to the same file(s) through different |
| File objects, channels, etc. |
| </p> |
| </div></div> |
| <div class="section"><h3>Approaches<a name="Approaches"></a></h3> |
| <a name="Approaches"></a> |
| <div class="section"><h4>The Simple Approach<a name="The_Simple_Approach"></a></h4> |
| <p> |
| The simplest approach for separating logging within applications is to package each application with |
| its own copy of Log4j and to use the BasicContextSelector. While this works for standalone applications |
| and may work for web applications and possibly Java EE applications, it does not work at all in the |
| last case. However, when this approach does work it should be used as it is ultimately the simplest |
| and most straightforward way of implementing logging. |
| </p> |
| |
| </div><div class="section"><h4>Using Context Selectors<a name="Using_Context_Selectors"></a></h4> |
| <p> |
| There are a few patterns for achieving the desired state of logging separation using ContextSelectors: |
| </p> |
| <ol style="list-style-type: decimal"> |
| <li>Place the logging jars in the container's classpath and set the system property |
| "Log4jContextSelector" to "org.apache.logging.log4j.core.selector.BasicContextSelector". This will |
| create a single LoggerContext using a single configuration that will be shared across all |
| applications.</li> |
| <li> |
| Place the logging jars in the container's classpath and use the default ClassLoaderContextSelector. |
| Follow the <a href="webapp.html">instructions to initialize Log4j 2 in a web application</a>. Each |
| application can be configured to share the same configuration used at the container or can be |
| individually configured. If status logging is set to debug in the configuration there will be output |
| from when logging is initialized in the container and then again in each web application. |
| </li> |
| <li> |
| Follow the <a href="webapp.html">instructions to initialize Log4j 2 in a web application</a> and set |
| the system property or servlet context parameter <tt>Log4jContextSelector</tt> to |
| <kbd>org.apache.logging.log4j.core.selector.JndiContextSelector</kbd>. This will cause the container |
| to use JNDI to locate each web application's <tt>LoggerContext</tt>. Be sure to set the |
| <tt>isLog4jContextSelectorNamed</tt> context parameter to <kbd>true</kbd> and also set the |
| <tt>log4jContextName</tt> and <tt>log4jConfiguration</tt> context parameters. |
| </li> |
| </ol> |
| <p> |
| The exact method for setting system properties depends on the container. For Tomcat, edit |
| <tt>$CATALINA_HOME/conf/catalina.properties</tt>. Consult the documentation for other web containers. |
| </p> |
| </div></div> |
| </div> |
| |
| |
| </td> |
| </tr> |
| </table> |
| </div> |
| |
| <div class="footer"> |
| <p>Copyright © 1999-2014 <a class="external" href="http://www.apache.org">Apache Software Foundation</a>. All Rights Reserved.</p> |
| <p>Apache Logging, Apache Log4j, Log4j, Apache, the Apache feather logo, and the Apache Logging project logo are trademarks of The Apache Software Foundation.</p> |
| <p>Site powered by <a class="external" href="http://twitter.github.com/bootstrap/">Twitter Bootstrap</a>. Icons from <a class="external" href="http://glyphicons.com/">Glyphicons Free</a>.</p> |
| </div> |
| </div> |
| </body> |
| </html> |
