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   <title>Example: Centralized Logging with Logback</title><link rel="stylesheet" type="text/css" href="css/docbook.css"><meta name="generator" content="DocBook XSL Stylesheets V1.79.1"><meta name="keywords" content="jetty, servlet, servlet-api, cometd, http, websocket, eclipse, maven, java, server, software"><link rel="home" href="index.html" title="Jetty"><link rel="up" href="configuring-logging.html" title="Chapter&nbsp;11.&nbsp;Jetty Logging"><link rel="prev" href="example-slf4j-multiple-loggers.html" title="Example: Capturing Multiple Logging Frameworks with Slf4j"><link rel="next" href="jetty-dump-tool.html" title="Jetty Dump Tool"><link xmlns:jfetch="java:org.eclipse.jetty.xslt.tools.JavaSourceFetchExtension" xmlns:fetch="java:org.eclipse.jetty.xslt.tools.SourceFetchExtension" xmlns:d="http://docbook.org/ns/docbook" xmlns:l="http://docbook.sourceforge.net/xmlns/l10n/1.0" xmlns:xslthl="http://xslthl.sf.net" xmlns:gcse="http://www.google.com" xmlns:date="http://exslt.org/dates-and-times" rel="shortcut icon" href="images/favicon.ico"><link rel="stylesheet" href="css/highlighter/foundation.css"><script src="js/highlight.pack.js"></script><script>
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            Version: 9.3.28.v20191105</span></td><td style="width: 50%"></td></tr></table><div xmlns:jfetch="java:org.eclipse.jetty.xslt.tools.JavaSourceFetchExtension" xmlns:fetch="java:org.eclipse.jetty.xslt.tools.SourceFetchExtension" xmlns:d="http://docbook.org/ns/docbook" xmlns:l="http://docbook.sourceforge.net/xmlns/l10n/1.0" xmlns:xslthl="http://xslthl.sf.net" xmlns:gcse="http://www.google.com" xmlns:date="http://exslt.org/dates-and-times" class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="3" align="center">Example: Centralized Logging with Logback</th></tr><tr><td width="20%" align="left"><a accesskey="p" href="example-slf4j-multiple-loggers.html"><i class="fa fa-chevron-left" aria-hidden="true"></i> Previous</a>&nbsp;</td><th width="60%" align="center">Chapter&nbsp;11.&nbsp;Jetty Logging<br><a accesskey="p" href="index.html"><i class="fa fa-home" aria-hidden="true"></i> Home</a></th><td width="20%" align="right">&nbsp;<a accesskey="n" href="jetty-dump-tool.html">Next <i class="fa fa-chevron-right" aria-hidden="true"></i></a></td></tr></table><hr></div><div xmlns:jfetch="java:org.eclipse.jetty.xslt.tools.JavaSourceFetchExtension" xmlns:fetch="java:org.eclipse.jetty.xslt.tools.SourceFetchExtension" xmlns:d="http://docbook.org/ns/docbook" xmlns:l="http://docbook.sourceforge.net/xmlns/l10n/1.0" xmlns:xslthl="http://xslthl.sf.net" xmlns:gcse="http://www.google.com" xmlns:date="http://exslt.org/dates-and-times" class="jetty-callout"><h5 class="callout"><a href="http://www.webtide.com/">Contact the core Jetty developers at
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      </p></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="example-logging-logback-centralized"></a>Example: Centralized Logging with Logback</h2></div></div></div><p>The term <span class="emphasis"><em>Centralized Logging</em></span> refers to a forced logging configuration for the Jetty Server and all web applications that are deployed on the server.
It routes all logging events from the web applications to a single configuration on the Server side.</p><p>The example below shows how to accomplish this with Jetty and Slf4j, using <code class="literal">Logback</code> to manage the final writing of logs to disk.</p><div class="blockquote"><blockquote class="blockquote"><div xmlns:jfetch="java:org.eclipse.jetty.xslt.tools.JavaSourceFetchExtension" xmlns:fetch="java:org.eclipse.jetty.xslt.tools.SourceFetchExtension" xmlns:d="http://docbook.org/ns/docbook" xmlns:l="http://docbook.sourceforge.net/xmlns/l10n/1.0" xmlns:xslthl="http://xslthl.sf.net" xmlns:gcse="http://www.google.com" xmlns:date="http://exslt.org/dates-and-times" class="important" style="margin-left: 0.5in; margin-right: 0.5in;"><h3 class="title"><i class="fa fa-plus" aria-hidden="true"></i> Important</h3><p>This mechanism forces all webapps to use the server&#8217;s configuration for logging, something that isn&#8217;t 100% appropriate for all webapps.
An example would be having Jenkins-CI deployed as an webapp, if you force its logging configuration to the server side, you lose the ability on <a class="link" href="http://jenkins-ci.org/" target="_top">Jenkins-CI</a> to see the logs from the various builds (as now those logs are actually going to the main server log).</p></div></blockquote></div><p>This configuration is essentially the multiple logger configuration with added configuration to the deployers to force a <code class="literal">WebAppClassLoader</code> change to use the server classpath over the webapps classpath for the logger specific classes.</p><p>The technique used by this configuration is to provide an <a class="link" href="http://www.eclipse.org/jetty/javadoc/9.3.28.v20191105org/eclipse/jetty/deploy/AppLifeCycle.Binding.html" target="_top">AppLifeCycle.Binding</a> against the <a class="link" href="http://www.eclipse.org/jetty/javadoc/9.3.28.v20191105/org/eclipse/jetty/deploy/AppLifeCycle.html" target="_top">`"deploying"`node</a> that modifies the <a class="link" href="http://www.eclipse.org/jetty/javadoc/9.3.28.v20191105/org/eclipse/jetty/webapp/WebAppContext.html#addSystemClass(java.lang.String)" target="_top">WebAppContext.addSystemClass(String)</a> for the common logging classes.
See <a class="link" href="https://github.com/jetty-project/jetty-webapp-logging/blob/master/src/main/java/org/eclipse/jetty/webapp/logging/CentralizedWebAppLoggingBinding.java" target="_top">org.eclipse.jetty.logging.CentralizedWebAppLoggingBinding</a> for actual implementation.</p><p>A convenient replacement <code class="literal">logging</code> module has been created to bootstrap your <code class="literal">${jetty.base}</code> directory for capturing all Jetty server logging from multiple logging frameworks into a single logging output file managed by Logback.</p><div class="screenexample"><pre class="screen">[mybase]$ mkdir modules
[mybase]$ cd modules

[modules]$ curl -O https://raw.githubusercontent.com/jetty-project/logging-modules/master/capture-all/logging.mod
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
100  1416  100  1416    0     0   4241      0 --:--:-- --:--:-- --:--:--  4252

[master]$ curl -O https://raw.githubusercontent.com/jetty-project/logging-modules/master/centralized/webapp-logging.mod
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
100   660  100   660    0     0   2032      0 --:--:-- --:--:-- --:--:--  2037
[modules]$ cd ..

[mybase]$ java -jar /opt/jetty-dist/start.jar --add-to-start=logging,webapp-logging
INFO: logging         initialised in ${jetty.base}/start.ini (appended)
MKDIR: ${jetty.base}/logs
DOWNLOAD: http://central.maven.org/maven2/org/slf4j/slf4j-api/1.6.6/slf4j-api-1.6.6.jar to lib/logging/slf4j-api-1.6.6.jar
DOWNLOAD: http://central.maven.org/maven2/org/slf4j/log4j-over-slf4j/1.6.6/log4j-over-slf4j-1.6.6.jar to lib/logging/log4j-over-slf4j-1.6.6.jar
DOWNLOAD: http://central.maven.org/maven2/org/slf4j/jul-to-slf4j/1.6.6/jul-to-slf4j-1.6.6.jar to lib/logging/jul-to-slf4j-1.6.6.jar
DOWNLOAD: http://central.maven.org/maven2/org/slf4j/jcl-over-slf4j/1.6.6/jcl-over-slf4j-1.6.6.jar to lib/logging/jcl-over-slf4j-1.6.6.jar
DOWNLOAD: http://central.maven.org/maven2/ch/qos/logback/logback-core/1.0.7/logback-core-1.0.7.jar to lib/logging/logback-core-1.0.7.jar
DOWNLOAD: http://central.maven.org/maven2/ch/qos/logback/logback-classic/1.0.7/logback-classic-1.0.7.jar to lib/logging/logback-classic-1.0.7.jar
DOWNLOAD: https://raw.githubusercontent.com/jetty-project/logging-modules/master/capture-all/logback.xml to resources/logback.xml
DOWNLOAD: https://raw.githubusercontent.com/jetty-project/logging-modules/master/capture-all/jetty-logging.properties to resources/jetty-logging.properties
DOWNLOAD: https://raw.githubusercontent.com/jetty-project/logging-modules/master/capture-all/jetty-logging.xml to etc/jetty-logging.xml
INFO: resources       initialised transitively
INFO: resources       enabled in     ${jetty.base}/start.ini
INFO: webapp-logging  initialised in ${jetty.base}/start.ini (appended)
DOWNLOAD: http://central.maven.org/maven2/org/eclipse/jetty/jetty-webapp-logging/9.0.0/jetty-webapp-logging-9.0.0.jar to lib/webapp-logging/jetty-webapp-logging-9.0.0.jar
DOWNLOAD: https://raw.githubusercontent.com/jetty-project/jetty-webapp-logging/master/src/main/config/etc/jetty-webapp-logging.xml to etc/jetty-webapp-logging.xml
DOWNLOAD: https://raw.githubusercontent.com/jetty-project/jetty-webapp-logging/master/src/main/config/etc/jetty-mdc-handler.xml to etc/jetty-mdc-handler.xml
INFO: deploy          initialised transitively
INFO: deploy          enabled in     ${jetty.base}/start.ini
INFO: logging         initialised transitively
INFO: resources       initialised transitively
INFO: resources       enabled in     ${jetty.base}/start.ini

[mybase]$ java -jar /opt/jetty-dist/start.jar</pre></div><p>The replacement <code class="literal">logging.mod</code> performs a number of tasks.</p><div class="orderedlist"><ol class="orderedlist" type="1"><li class="listitem"><code class="literal">mybase</code> is a <code class="literal">${jetty.base}</code> directory.</li><li class="listitem">The jetty-distribution is unpacked (and untouched) into <code class="literal">/opt/jetty-dist/</code> and becomes the <code class="literal">${jetty.home}</code> directory for this demonstration.</li><li class="listitem">The <code class="literal">curl</code> command downloads the replacement <code class="literal">logging.mod</code> and puts it into the <code class="literal">${jetty.base}/modules/</code> directory for use by mybase only.</li><li class="listitem"><p class="simpara">The <code class="literal">start.jar --add-to-start=logging,webapp-logging</code> command performs a number of steps to make the logging module available to the <code class="literal">${jetty.base}</code> configuration.</p><div class="orderedlist"><ol class="orderedlist" type="a"><li class="listitem"><p class="simpara">Several entries are added to the <code class="literal">${jetty.base}/start.ini</code> configuration.</p><div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem"><code class="literal">--module=logging</code> is added to enable the logging module.</li><li class="listitem"><code class="literal">--module=webapp-logging</code> is added to enable the webapp-logging module.</li></ul></div></li><li class="listitem">Required <code class="literal">${jetty.base}</code> directories are created: <code class="literal">${jetty.base}/logs</code> and <code class="literal">${jetty.base}/resources</code>.</li><li class="listitem"><p class="simpara">Required logging libraries are downloaded (if not present already) to the <code class="literal">${jetty.base}/lib/logging/</code> directory:</p><div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem"><code class="literal">slf4j-api.jar</code> - API jar for Slf4j (used by most of the rest of the jars)</li><li class="listitem"><code class="literal">log4j-over-slf4j.jar</code> - Slf4j jar that captures all log4j emitted logging events</li><li class="listitem"><code class="literal">jul-to-slf4j.jar</code> - Slf4j jar that captures all java.util.logging events</li><li class="listitem"><code class="literal">jcl-over-slf4j.jar</code> - Slf4j jar that captures all commons-logging events</li><li class="listitem"><code class="literal">logback-classic.jar</code> - the Slf4j adapter jar that routes all of the captured logging events to logback itself.</li><li class="listitem"><code class="literal">logback-core.jar</code> - the logback implementation jar, that handles all of the filtering and output of the logging events.</li></ul></div></li><li class="listitem"><p class="simpara">Required webapp-logging library is downloaded (if not present already) to the <code class="literal">${jetty.base}/lib/webapp-logging/</code> directory:</p><div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem"><code class="literal">jetty-webapp-logging.jar</code> - the Jetty side deployment manger app-lifecycle bindings for modifying the <code class="literal">WebAppClassloaders</code> of deployed webapps.</li></ul></div></li><li class="listitem">Required configuration files are downloaded (if not present already) to the <code class="literal">${jetty.base}/resources/</code> directory: <code class="literal">jetty-logging.properties</code>, and <code class="literal">logback.xml</code>.</li><li class="listitem">Required initialization commands are downloaded (if not present already) to the <code class="literal">${jetty.base}/etc/</code> directory: <code class="literal">jetty-logging.xml</code>, <code class="literal">jetty-webapp-logging.xml</code>, and <code class="literal">jetty-mdc-handler.xml</code>.</li></ol></div></li></ol></div><p>At this point the Jetty <code class="literal">mybase</code> is configured so that the jetty server itself will log using slf4j, and all other logging events from other Jetty Server components (such as database drivers, security layers, jsp, mail, and other 3rd party server components) are routed to logback for filtering and output.</p><p>All webapps deployed via the <code class="literal">DeploymentManager</code> have their <code class="literal">WebAppClassLoader</code> modified to use server side classes and configuration for all logging implementations.</p><p>The server classpath can be verified by using the <code class="literal">start.jar --list-config</code> command.</p><p>In essence, Jetty is now configured to emit its own logging events to slf4j, and various slf4j bridge jars are acting on behalf of log4j, <code class="literal">java.util.logging</code>, and <code class="literal">commons-logging</code>, routing all of the logging events to logback (a slf4j adapter) for routing (to console, file, etc&#8230;&#8203;).</p></div><script type="text/javascript">
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