![]() Version: 9.4.29.v20200521 |
private support for your internal/customer projects ... custom extensions and distributions ... versioned snapshots for indefinite support ... scalability guidance for your apps and Ajax/Comet projects ... development services for sponsored feature development
The term Centralized Logging 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.
The example below shows how to accomplish this with Jetty and Slf4j, using Logback
to manage the final writing of logs to disk.
Important
This mechanism forces all webapps to use the server’s configuration for logging, something that isn’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 Jenkins-CI to see the logs from the various builds (as now those logs are actually going to the main server log).
This configuration is essentially the multiple logger configuration with added configuration to the deployers to force a WebAppClassLoader
change to use the server classpath over the webapps classpath for the logger specific classes.
The technique used by this configuration is to provide an AppLifeCycle.Binding against the `"deploying"`node that modifies the WebAppContext.getSystemClasspathPattern().add(String) for the common logging classes. See org.eclipse.jetty.logging.CentralizedWebAppLoggingBinding for actual implementation.
A convenient replacement logging
module has been created to bootstrap your ${jetty.base}
directory for capturing all Jetty server logging from multiple logging frameworks into a single logging output file managed by Logback.
[mybase]$ curl -O https://repo1.maven.org/maven2/org/eclipse/jetty/jetty-webapp-logging/9.4.27/jetty-webapp-logging-9.4.27-config.jar % Total % Received % Xferd Average Speed Time Time Time Current Dload Upload Total Spent Left Speed 100 3402 100 3402 0 0 15823 0 --:--:-- --:--:-- --:--:-- 15750 [mybase]$ jar -xf jetty-webapp-logging-9.4.27-config.jar [mybase]$ java -jar /opt/jetty-hom/start.jar --create-startd --add-to-start=centralized-webapp-logging ALERT: There are enabled module(s) with licenses. The following 2 module(s): + contains software not provided by the Eclipse Foundation! + contains software not covered by the Eclipse Public License! + has not been audited for compliance with its license Module: logback-impl + Logback: the reliable, generic, fast and flexible logging framework. + Copyright (C) 1999-2012, QOS.ch. All rights reserved. + This program and the accompanying materials are dual-licensed under + either: + the terms of the Eclipse Public License v1.0 + as published by the Eclipse Foundation: + http://www.eclipse.org/legal/epl-v10.html + or (per the licensee's choosing) under + the terms of the GNU Lesser General Public License version 2.1 + as published by the Free Software Foundation: + http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html Module: slf4j-api + SLF4J is distributed under the MIT License. + Copyright (c) 2004-2013 QOS.ch + All rights reserved. + Permission is hereby granted, free of charge, to any person obtaining + a copy of this software and associated documentation files (the + "Software"), to deal in the Software without restriction, including + without limitation the rights to use, copy, modify, merge, publish, + distribute, sublicense, and/or sell copies of the Software, and to + permit persons to whom the Software is furnished to do so, subject to + the following conditions: + The above copyright notice and this permission notice shall be + included in all copies or substantial portions of the Software. + THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, + EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF + MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND + NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE + LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION + OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION + WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. Proceed (y/N)? y INFO : slf4j-api transitively enabled INFO : log4j-over-slf4j transitively enabled INFO : jcl-slf4j transitively enabled INFO : logback-impl transitively enabled INFO : jul-slf4j transitively enabled INFO : slf4j-logback transitively enabled INFO : centralized-webapp-logging initialized in ${jetty.base}/start.d/centralized-webapp-logging.ini INFO : logging-logback transitively enabled INFO : resources transitively enabled MKDIR : ${jetty.base}/lib/slf4j DOWNLD: https://repo1.maven.org/maven2/org/slf4j/slf4j-api/1.7.25/slf4j-api-1.7.25.jar to ${jetty.base}/lib/slf4j/slf4j-api-1.7.25.jar MKDIR : ${jetty.base}/lib/logging DOWNLD: https://repo1.maven.org/maven2/org/slf4j/log4j-over-slf4j/1.7.25/log4j-over-slf4j-1.7.25.jar to ${jetty.base}/lib/logging/log4j-over-slf4j-1.7.25.jar DOWNLD: https://repo1.maven.org/maven2/org/slf4j/jcl-over-slf4j/1.7.25/jcl-over-slf4j-1.7.25.jar to ${jetty.base}/lib/slf4j/jcl-over-slf4j-1.7.25.jar MKDIR : ${jetty.base}/lib/logback DOWNLD: https://repo1.maven.org/maven2/ch/qos/logback/logback-core/1.2.3/logback-core-1.2.3.jar to ${jetty.base}/lib/logback/logback-core-1.2.3.jar DOWNLD: https://repo1.maven.org/maven2/org/slf4j/jul-to-slf4j/1.7.25/jul-to-slf4j-1.7.25.jar to ${jetty.base}/lib/slf4j/jul-to-slf4j-1.7.25.jar COPY : ${jetty.home}/modules/jul-slf4j/etc/java-util-logging.properties to ${jetty.base}/etc/java-util-logging.properties DOWNLD: https://repo1.maven.org/maven2/ch/qos/logback/logback-classic/1.2.3/logback-classic-1.2.3.jar to ${jetty.base}/lib/logback/logback-classic-1.2.3.jar MKDIR : ${jetty.base}/logs DOWNLD: https://repo1.maven.org/maven2/org/eclipse/jetty/jetty-webapp-logging/9.4.27/jetty-webapp-logging-9.4.27.jar to ${jetty.base}/lib/logging/jetty-webapp-logging-9.4.27.jar INFO : Base directory was modified $
This replacement centralized-webapp-logging.mod
performs a number of tasks.
mybase
is a ${jetty.base}
directory./opt/jetty-dist/
and becomes the ${jetty.home}
directory for this demonstration.curl
command downloads the replacement config overlay for the ${jetty.base}/modules/
directory to use.The start.jar --add-to-start=centralized-webapp-logging
command performs a number of steps to make the centralized-webapp-logging module available to the ${jetty.base}
configuration.
${jetty.base}/start.d/centralized-webapp-logging.ini
configuration was created.${jetty.base}
directories are created: ${jetty.base}/logs
and ${jetty.base}/resources
.Required logging libraries are downloaded (if not present already) to the ${jetty.base}/lib/logging/
directory:
slf4j-api.jar
- API jar for Slf4j (used by most of the rest of the jars)log4j-over-slf4j.jar
- Slf4j jar that captures all log4j emitted logging eventsjul-to-slf4j.jar
- Slf4j jar that captures all java.util.logging eventsjcl-over-slf4j.jar
- Slf4j jar that captures all commons-logging eventslogback-classic.jar
- the Slf4j adapter jar that routes all of the captured logging events to logback itself.logback-core.jar
- the logback implementation jar, that handles all of the filtering and output of the logging events.Required webapp-logging library is downloaded (if not present already) to the ${jetty.base}/lib/webapp-logging/
directory:
jetty-webapp-logging.jar
- the Jetty side deployment manger app-lifecycle bindings for modifying the WebAppClassloaders
of deployed webapps.At this point the Jetty mybase
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.
All webapps deployed via the DeploymentManager
have their WebAppClassLoader
modified to use server side classes and configuration for all logging implementations.
The server classpath can be verified by using the start.jar --list-config
command.
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
, java.util.logging
, and commons-logging
, routing all of the logging events to logback
(a slf4j implementation) for routing (to console, file, etc…).