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Gant is Groovy

Gant is a build tool for scripting Ant tasks using Groovy instead of XML to specify the build logic. A Gant build specification is a Groovy script and so can bring all the power of Groovy to bear directly, something not possible with Ant scripts. Whilst it might be seen as a competitor to Ant, Gant uses Ant tasks for many of the actions, so Gant is really an alternative way of doing builds using Ant, but using a programming language rather than XML to specify the build rules.
Here is an example Gant script:

In this script there are two targets, stuff and otherStuff -- the default target for this build is designated as stuff and is the target run when Gant is executed from the command line with no target as parameter.

Targets are closures so they can be called as functions, in which case they are executed as you expect, or they can be dependencies to other targets by being parameters to the depends function, in which case they are executed if an only if they have not been executed already in this run. (There is a page with some more information on Targets.)

You may be wondering about the stuff at the beginning of the script. Gant has two ways of using pre-built sub-scripts, either textual inclusion of another Gant script or the inclusion of a pre-compiled class. The example here shows the latter -- the class gant.targets.Clean is a class that provides simple clean capabilities.

The default name for the Gant script is build.gant, in the same way that the default for an Ant build script in build.xml. 

Gant provides a way of finding what the documented targets are:

The messages on this output are exactly the strings associated with the target name in the introduction to the target.

Gant "eats its own dog food"

Gant can build and install itself and is being used for various build tasks including building Groovy and Java programs, static websites, LaTeX documents. The ability to have arbitrary Groovy methods within the build scripts makes a Gant build script so much easier to work with that the mix of XML and Groovy scripts that using Ant necessitates. But then maybe this is an issue of individual perception. But then Gant is not about replacing Ant, it is about having a different way of working with the tasks and infrastructure that Ant provides.

More details about Gant

Some pages providing more details:

Getting Gant

Gant is currently at version 1.3.0. The following downloads are available:

1.3.0 Source

Tarball

Zipfile

1.3.0 Binary, compiled for use with Groovy 1.5.6 installation

Tarball

Zipfile

1.3.0 Binary, compiled for use with Groovy 1.6-beta-1-SNAPSHOT installation

Tarball

Zipfile

1.3.0 Binary, standalone installation

Tarball

Zipfile

Installation of any of the binary distributions is simply a matter of extracting the distribution to the desired location. A directory gant-1.3.0 will be created.

The jar and pom have been uploaded to the Codehaus Maven repository, the groupId is org.codehaus.gant, the artifactId is gant and the version is 1.3.0.

Ubuntu and Debian users can install Gant using the usual package management system (apt-get and/or dpkg). There is a deb file that depends on Groovy 1.5.6 or later being installed:

Gant 1.3.0 requiring Groovy

Deb

and one that installs as a standalone system with no dependency on Groovy (a groovy-all jar is included in the package along with various transitive dependencies):

Gant 1.3.0 standalone

Deb

Lenny (testing) has Gant 1.2.0 http://packages.debian.org/lenny/gant as does Sid (unstable) http://packages.debian.org/sid/gant, both are dependent on Groovy which in both distributions is 1.5.6. Ubuntu does not yet have Gant in the distribution.

Ealier distributions are available at http://dist.codehaus.org/gant/distributions as are snapshots of the next release, if available.

If you would prefer to work with the version from the Gant Subversion repository, you can get a checkout using Subversion by:

For those who would like to work on the code creating patches for submission, you will want to use a distributed version control system. Bazaar and Git have good tools for working with a Subversion repository. Using Bazaar, you can take a branch of the Subversion repository by:

Ready-made, up-to-date branches are held at:

and

In particular there is a branch that is an automated mirror of the subversion repository:

and a branch updated manually from my personal branch:

Gant is the main tool for working with the Gant checkout, but (obviously (smile) the first time you want to install Gant from a checkout there is no Gant to build and install Gant. To cover this situation there is an Ant build script for bootstrapping.

Endnote

If you give it a go and have some feedback, do let me know either on the Gant User mailing list or perhaps the Groovy User mailing list, or by direct email to me russel.winder@concertant.com

BTW Gant is not a toy, it is used for task management in Grails! In fact there is a very nice page on the Grails site showing how Gant scripts can be used in Grails.

If you have any issues with Gant then please add a JIRA issue into the Gant JIRA at Codehaus. The URL is http://jira.codehaus.org/secure/CreateIssue!default.jspa

Russel Winder

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