Grails - Maven Integration

The current Maven plugin is based on, but effectively supercedes, the version created by the guys at Octo who did a great job. Until this page is updated, you'll still want to use the documenation over at octo.

Preparation

The Maven 2 integration for Grails has been designed and tested for Maven 2.0.9 and above and will not work with prior versions of Maven 2

In order to try the new plugin, all you need is Maven 2 installed and set up. In fact, you should unset the GRAILS_HOME environment variable when running Maven with a Grails project. This is because you no longer need to install Grails separately to use it with Maven!

If you are running grails 1.2-M3, you must set GRAILS_HOME due to GRAILS-5220 (Fixed in Grails 1.2-M4)

One piece of configuration that may help is setting up a plugin group in your Maven settings file ( $HOME/.m2/settings.xml ):

<settings>
  …
  <pluginGroups>
    <pluginGroup>org.grails</pluginGroup>
  </pluginGroups>
</settings>

Also, remove the com.octo.mtg plugin group if you have it set up.

Just do it!

Without further ado, let's create our Mavenised Grails project:

mvn org.apache.maven.plugins:maven-archetype-plugin:2.0-alpha-4:generate \
    -DarchetypeGroupId=org.grails \
    -DarchetypeArtifactId=grails-maven-archetype \
    -DarchetypeVersion=1.2.0 \
    -DgroupId=example -DartifactId=my-app

Choose whichever group ID and artifact ID you want for your application, but everything else must be as written. This will create a new Maven project with a POM and a couple of other files. What you won't see is anything that looks like a Grails application. So, the next step is to create the project structure that you're used to:

mvn initialize

Now we have a Grails application all ready to go. The plugin integrates into the standard build cycle, so you can use the standard Maven phases to build and package your app: mvn clean , mvn compile , mvn test , mvn package .

You can also take advantage of some of the Grails commands that have been wrapped as Maven goals:

grails:console
grails:create-controller
grails:create-domain-class
grails:create-integration-test
grails:create-pom
grails:create-script
grails:create-service
grails:create-tag-lib
grails:create-unit-test
grails:exec
grails:generate-all
grails:generate-controller
grails:generate-views
grails:install-plugin
grails:install-templates
grails:list-plugins
grails:package
grails:run-app
grails:run-app-https
grails:uninstall-plugin

Example Usage

(first execute archetype as above to create your project)

mvn grails:list-plugins

mvn grails:install-plugin -DpluginName=jsecurity

mvn initialize

Debugging

Maven can be launched in debug mode using the "mvnDebug" command. To launch your Grails application in debug, simply run:

mvnDebug grails:run-app

The process will be suspended on startup and listening for a debugger on port 8000.

If you need more control of the debugger, this can be specified using the MAVEN_OPTS environment variable, and launch Maven via the default "mvn" command:

MAVEN_OPTS="-Xdebug 
-Xrunjdwp:transport=dt_socket,server=y,suspend=y,address=5005" mvn grails:run-app

Executing scripts

Some plugins have extra scripts for generating config files or other artifacts. For instance, the Quartz plugin has a create-job script which is invoked in a non-Maven environment via:

grails create-job

Execute scripts like this in a Maven environment this way:

mvn grails:exec -Dcommand="create-job"

Other versions

During the beta and RC cycles, several versions of the plugin and archetype are released. Here's a table of the versions you need to use for a given version of Grails:

Grails	Plugin	Archetype
1.1-beta1	-	-
1.1-beta2	0.4	1.0-beta2
1.1-beta3	1.0-beta3	1.0-beta3
1.1-RC1	1.0-RC1	1.0-RC1
1.1-RC2	1.0-RC2	1.0-RC2
1.1-SNAPSHOT	1.0-SNAPSHOT	1.0-SNAPSHOT
1.1	1.0	1.0
1.1.1	1.1	1.1
1.2.0	1.2.0	1.2.0

Raising issues

If you come across any problems with the Maven integration, please raise a JIRA issue as a sub-task of GRAILS-3547.