maven

Java JSP Jetty Maven Docker example

Clone this repository with git clone https://github.com/danial-k/docker-intro.git and open docker-intro/maven in an ide.

Alternatively, to skip cloning and use these instructions directly, create a new directory for this example:

mkdir -p docker-intro/maven
cd docker-intro/maven

Setting up development container

Start a Maven development container with:

docker run \
-it \
--name maven \
--hostname maven \
--mount type=bind,src=`pwd`/app,dst=/app \
--publish 3010:8080/tcp \
-w //app \
maven:3.6-jdk-8 \
bash

Create an empty JSP application using Maven's Archetype generator:

mvn archetype:generate \
-DarchetypeGroupId=org.apache.maven.archetypes \
-DarchetypeArtifactId=maven-archetype-webapp \
-DarchetypeVersion=1.4 \
-DinteractiveMode=false \
-DgroupId=com.example \
-DartifactId=app \
-Dversion=1.0-SNAPSHOT

Move the contents of the generated project to the parent directory and remove the empty directory:

mv app/* . && rm -rf app

The project source files should now be accessible to an IDE (e.g. app/src/main/webapp/index.jsp). To run a Maven Jetty webserver, add the following to the project pom.xml under build.pluginManagement.plugins:

...
<plugin>
  <groupId>org.eclipse.jetty</groupId>
  <artifactId>jetty-maven-plugin</artifactId>
  <version>9.2.21.v20170120</version>
</plugin>
...

Run the web project with the Maven Jetty plugin:

mvn jetty:run

The application should now be visible at http://127.0.0.1:3010.

Although the application is now functional, it is running on a development-focused base image (~500 MB). In production, this would run on an optimised Jetty base image (~260 MB) per the following section.

Building deployment container

To publish the application as a self-contained image, we will use a multi-stage build process (see the Dockerfile[Dockerfile] for this project (place in the maven directory). This Dockerfile will first build the source (using on the Maven image) and then produce a deployable image (based on the Jetty image):

docker build -t jsp-maven:1.0.0 .

This will send all files in the current directory to the Docker daemon's build context (excluding paths specified in .dockerignore), then create and tag the image. With the target folder excluded, the build context is approximately 15KB, whereas without this exlusion the context increases to 30 KB. Once the image has been built, run with:

docker run -p 3011:8080 jsp-maven:1.0.0

The application should now be visible at http://127.0.0.1:3011/app.