Please note, before we really get started, that what we're doing here is removing support for juli and replacing it with Logback support. juli refers to Tomcat's own implementation of key elements of the java.util.logging API. Since version 6, Tomcat has used a private, package-renamed implementation of Apache Commons Logging in order to allow applications to use their own independent copies of the Apache Commons Logging library. It's hard-coded to be simplified and based on juli.
To configure Tomcat to use alternative logging frameworks, like Logback, one must replace the logging library with the one built using the full implementation. Apache claims that a web application can use any logging framework of its choice.
Whatever is supposed to work, it's pretty clear that if you want to use Logback, any logback.xml internal to your application, typically on the path WEB-INF/classes, is ignored and, while logging works, for example, Logback with an slf4j façade, happens with a default configuration as if logback.xml (or its alternates) weren't even there. In other words, if you promote a package to TRACE, it will likely come out in the system console of your IDE's unit testing, but it won't reach catalina.out in your production Tomcat (or even your IDE's notion of catalina.out when running on its "internal" Tomcat).
In my experience with Tomcat, log4j and logback used in my application are not configurable. I only get INFO-level statements. Others must have realized this as well; hence the implementation here (the first one).
Because ultimately, we don't want to have to muck up Tomcat every time we down-load a fresh one.
This is our second try (the first is down at the end of this document. Follow these linked instructions...
I downloaded another copy of Tomcat 9 for the purpose of bastardizing it with the changes suggested by the links above. I record the steps as I make this happen:
russ@tirion ~/dev $ tar -zxf apache-tomcat-9.0.60.tar.gz
Downloads from the linked instructions in item C of the list way above. In bold, what we need in Dockerfile. (We won't build our new Dockerfile until after trying out these changes to make sure they work.)
russ@tirion ~/Downloads/tomcat-logback/slf4j $ ll total 2008 drwxrwxr-x 6 russ russ 4096 Mar 21 17:41 . drwxrwxr-x 3 russ russ 4096 Mar 21 17:35 .. drwxr-xr-x 2 russ russ 4096 May 19 2018 bin drwxr-xr-x 2 russ russ 4096 May 19 2018 conf drwxr-xr-x 2 russ russ 4096 May 19 2018 lib -rw-r--r-- 1 russ russ 11368 Mar 4 2017 LICENSE -rw-r--r-- 1 russ russ 471 Mar 4 2017 LICENSE-logback.txt -rw-r--r-- 1 russ russ 1135 Mar 4 2017 LICENSE-slf4j.txt -rw-r--r-- 1 russ russ 56814 Mar 4 2017 LICENSE-tomcat.txt drwxr-xr-x 2 russ russ 4096 Nov 20 2016 src -rw-rw-r-- 1 russ russ 1953493 Mar 21 17:37 tomcat-juli-9.0.14-slf4j-1.7.25-logback-1.2.3.zip russ@tirion ~/Downloads/tomcat-logback/slf4j $ ll bin total 896 drwxr-xr-x 2 russ russ 4096 May 19 2018 . drwxrwxr-x 6 russ russ 4096 Mar 21 17:41 .. -rw-r--r-- 1 russ russ 558 Feb 11 2018 setenv.bat -rw-r--r-- 1 russ russ 519 Mar 4 2017 setenv.sh -rw-r--r-- 1 russ russ 899180 May 19 2018 tomcat-juli.jar russ@tirion ~/Downloads/tomcat-logback/slf4j $ ll conf total 28 drwxr-xr-x 2 russ russ 4096 May 19 2018 . drwxrwxr-x 6 russ russ 4096 Mar 21 17:41 .. -rw-r--r-- 1 russ russ 1533 Mar 18 2018 logback-access.xml -rw-r--r-- 1 russ russ 4554 Apr 8 2018 logback.xml -rw-r--r-- 1 russ russ 7391 Mar 4 2017 server.xml russ@tirion ~/Downloads/tomcat-logback/slf4j $ ll lib total 580 drwxr-xr-x 2 russ russ 4096 May 19 2018 . drwxrwxr-x 6 russ russ 4096 Mar 21 17:41 .. -rw-r--r-- 1 russ russ 107064 Apr 14 2017 logback-access-1.2.3.jar -rw-r--r-- 1 russ russ 471901 Apr 5 2017 logback-core-1.2.3.jar
Perform steps below in ~/Downloads/tomcat-logback.
$ diff ./setenv.sh ~/dev/apache-tomcat-9.0.60/bin/setenv.sh diff: /home/russ/dev/apache-tomcat-9.0.60/bin/setenv.sh: No such file or directory $ cp setenv.sh ~/dev/apache-tomcat-9.0.60/bin $ cp tomcat-juli.jar ~/dev/apache-tomcat-9.0.60/bin : 46895 Mar 9 07:52 tomcat-juli.jar (original) 899180 Mar 23 11:11 tomcat-juli.jar (replacement)
$ cp logback-access.xml ~/dev/apache-tomcat-9.0.60/conf $ cp logback.xml ~/dev/apache-tomcat-9.0.60/conf $ diff server.xml ~/dev/apache-tomcat-9.0.60/conf/server.xml 160c163,165 < <Valve className="ch.qos.logback.access.tomcat.LogbackValve" quiet="true" /> --- > <Valve className="org.apache.catalina.valves.AccessLogValve" directory="logs" > prefix="localhost_access_log" suffix=".txt" > pattern="%h %l %u %t "%r" %s %b" />
You see that we're replacing the standard log valve that ships with the Tomcat distro with one that supports Logback.
$ cp logback-access-1.2.3.jar ~/dev/apache-tomcat-9.0.60/lib $ cp logback-core-1.2.3.jar ~/dev/apache-tomcat-9.0.60/lib
~/dev/apache-tomcat-9.0.60/bin $ ./bin/startup.sh ~/dev/apache-tomcat-9.0.60/logs $ tail -f catalina.out ...after deploying a web application making TRACE statements ...and while using Postman to fire a request off to that web application.
Did you misspell LogbackValve as LogBackValve in server.xml?
Do you have another instance of Tomcat running or yet another process claiming the port configured in server.xml? Perhaps you forgot to work around that. Change 8080 to something else, 8443 to something else and 8005 to yet something else.
Aborted since it's too difficult if not impossible to get Tomcat to accommodate the use of Logback from web applications.
# Must use Tomcat 9 because Tomcat 10 doesn't work. FROM tomcat:9.0.58-jdk8-openjdk-slim LABEL maintainer="[email protected]" # Special instructions: ADD tomcat-logback-sources/tomcat-juli.jar bin/ ADD tomcat-logback-sources/setenv.sh bin/ ADD tomcat-logback-sources/logback.xml conf/ ADD tomcat-logback-sources/logback-access.xml conf/ ADD tomcat-logback-sources/server.xml conf/ ADD tomcat-logback-sources/logback-core-*.jar lib/ ADD tomcat-logback-sources/logback-access-*.jar lib/ RUN rm -r conf/logging.properties ... RUN echo 'alias ll="ls -alg"' >> ~/.bashrc ADD "target/mdht-restlet##*.war" /usr/local/tomcat/webapps EXPOSE 8080 CMD [ "catalina.sh", "run" ]
Our derivative container worked, but it didn't solve the problem: web applications deployed to Tomcat simply cannot make use of Logback.
# Must use Tomcat 9 because Tomcat 10 doesn't work. FROM camptocamp/tomcat-logback:9.0-jre11 LABEL maintainer="[email protected]" ADD "target/mdht-restlet##*.war" /usr/local/tomcat/webapps RUN echo 'alias ll="ls -alg"' >> ~/.bashrc EXPOSE 8080 CMD [ "catalina.sh", "run" ]
In the main console where we run Docker...
$ docker build -t mmmm . $ docker images $ docker run --name mdht-restlet2 -p 4040:8080 mmmm
In another console...
$ docker ps $ docker exec -it mdht-restlet2 /bin/bash # Once inside the container: # cd webapps # cd webapps/mdht-restlet##3.3.6-10/WEB-INF/classes/ # cat logback.xml # No catalina.out because container puts them on stdout in the console
This did not work: no TRACE statements came out. It's unclear, but as I don't have control over the Docker image, I am impeded. CampToCamp may simply have botched it. Let's build our own, besides, CampToCamp made choices I don't like (like to-stdout instead of catalina.out).