Multi-module Maven project and jetty:run

Question

I'm trying to split a Maven WAR project into two modules, so that I can build a separate JAR file with command line tools. The result has the following structure:

• pom.xml (packaging pom, has two modules)
• project-jar/
  • pom.xml (packaging jar)
• project-war/
  • pom.xml (packaging war, depends on project-jar)

If I run mvn commands from the root, everything works fine. I'd like to keep using mvn jetty:run, but for that I need to execute the command in the WAR subproject. If I do that, fails to find the project-jar subproject, so it won't run. Even mvn jetty:run-war with a completely assembled WAR file in the target directory fails, because it first tries to "build" the project. I've only managed to make it work by installing project-jar into the local Maven repository, which isn't very nice.

Is there a way to use the Jetty plugin in a multi-module Maven configuration?

Answer 1

Create a profile inside the war module (project-war). Within this profile, configure jetty to attach to a lifecycle phase and execute the run goal explicitly. Now when maven runs from the toplevel project with that profile enabled, it will invoke jetty:run and have sister module dependency resolution (as is normal when executing maven commands from the toplevel project).

The example configuration, when placed in the pom.xml of the web module (project-war), arranges for jetty:run to execute during the test phase. (You may choose another phase, but make sure it's after compile.)

Run from toplevel: mvn test -Pjetty-run or mvn test -DskipTests=true -Pjetty-run. This will compile dependencies as required and make them available but invoke jetty:run within the correct module.

<profiles>
  ...
  <!-- With this profile, jetty will run during the "test" phase -->
  <profile>
    <id>jetty-run</id>
    <build>
      <plugins>
        <plugin>
          <groupId>org.mortbay.jetty</groupId>
          <artifactId>jetty-maven-plugin</artifactId>
          <version>7.1.6.v20100715</version>
          <configuration>
            ...
            <webAppSourceDirectory>
              ${project.build.directory}/${project.build.finalName}
            </webAppSourceDirectory>
            ...
          </configuration>
          <executions>
            <execution>
              <id>jetty-run</id>
              <phase>test</phase>
              <goals>
                <goal>run</goal>
              </goals>
            </execution>
          </executions>
        </plugin>
      </plugins>
    </build>
  </profile>
...
</profiles>

Answer 2

There is no magical solution and the only one I know is a bit hacky and rely on the extraClasspath element that you can use to declare extra class directories, relatively. Like this (from JETTY-662):

<plugin>
  <groupId>org.mortbay.jetty</groupId>
  <artifactId>jetty-maven-plugin</artifactId>
  <version>7.0.1.v20091125</version>
  <configuration>
    <scanIntervalSeconds>10</scanIntervalSeconds>
    <webAppConfig>
      <contextPath>/my-context</contextPath>
      <extraClasspath>target/classes;../my-jar-dependency/target/classes</extraClasspath>
    </webAppConfig>
    <scanTargets>
      <scanTarget>../my-jar-dependency/target/classes</scanTarget>
    </scanTargets>
  </configuration>
</plugin>

Answer 3

Add jetty plugin to the root pom and configure a contextHandler pointing to the desired war. This works for me in a project with multiple jar modules and two overlay wars.

<plugin>
<groupId>org.eclipse.jetty</groupId>
<artifactId>jetty-maven-plugin</artifactId>
<version>9.3.0.M2</version>
<configuration>
        <scanIntervalSeconds>10</scanIntervalSeconds>
        <contextHandlers>
            <contextHandler
                implementation="org.eclipse.jetty.maven.plugin.JettyWebAppContext">
                <war>${project.basedir}/project-war/target/project-war-${project.version}.war</war>
                <contextPath>/</contextPath>
            </contextHandler>
        </contextHandlers>
    </configuration>
</plugin>

http://eclipse.org/jetty/documentation/current/jetty-maven-plugin.html#running-more-than-one-webapp

Answer 4

Using extraClasspath in jetty configuration works... but for some reason, if dependant jars (from other modules) are outdated some things won't work correctly.

Answer 5

I know you're asking for plugin configuration, but you could just define the project in the maven command:

$ mvn jetty:run --projects project-war

Answer 6

The documentation for jetty:run notes that

As of Jetty 9.4.7, when using jetty:run in a multi-module build, it is no longer necessary to build each of the modules that form dependencies of the webapp first. Thus, if your webapp depends on other modules in your project and they are present in the reactor at the same time, jetty will use their compiled classes rather than their jar files from your local maven repository.

Thus, add the jetty-maven-plugin to the Maven root project and run mvn jetty:run