Hello, Alexandre and others.
First of all, I have to apologize for keeping Tycho development plans
and progress to myself. I would like to thank you for bringing this up
and will try to both explain our grand vision and what we already have
or will have implemented in the near future.
The big picture. Ultimately, we want tycho to be one-stop solution for
doing Eclipse and OSGi development with Maven 2 (actually, 3, more on
this later). We believe there are two distinct development workflows,
when developer explicitly creates and maintains OSGi manifest and other
Eclipse/OSGi metadata (we call it "manifest-first") and when OSGi
metadata is generated by the build based on information available from
pom.xml ("pom-first", naturally). We plan to support both development
workflows.
In manifest-first mode, tycho will use Eclipse/OSGi metadata and OSGi
rules to calculate project dependencies dynamically, at build time. It
will support all attributes supported by Eclipse OSGi resolver
(Require-Bundle, Import-Package, Eclipse-GenericRequire, etc). It will
use proper classpath access rules during compilation. It will support
all projects supported by PDE and will use PDE/JDT project metadata
where applicable. One important design goal is to make sure there is no
duplication of metadata between pom.xml files and Eclipse/OSGi config
files. In fact, tycho will support "pom-less" projects, where all
required build metadata is derived from Eclipse/OSGi config files.
In pom-first mode current plan is to provide similar set of features as
in felix/bnd plugin, although I do not know if we'll be able to share
any of the code. Additionally, Tycho will support Eclipse-friendlier
Require-Bundle and will provide better support for developing multiple
related OSGi bundles (I have not checked recently, so felix/bnd may
already support these).
In both modes tycho will support remote repositories both as source and
sink for artifacts. We plan to support maven repositories, p2 and update
sites, although level of support will likely vary. There will also be
integration between m2e, tycho and pde to make the three work nicely
together.
So these are the plans... Disclaimer: plans do change! ;-)
Now to what tycho is already able to do. Our first goal was to enable
m2e continues build, so we started with manifest-first mode and I
believe covered most of manifest-first features described above. Tycho
already uses Eclipse/OSGi metadata to resolve project dependencies by
OSGi rules and injects these dependencies into maven project model
dynamically, at build time. It supports bundle, fragment, feature and
update site projects (shame on me, but no RCP application yet). It knows
how to run junit test plugins using OSGi runtime. Two big features that
are still missing, are support for pom-less projects and work with
artifact repositories, although there is prototype of target platform
materialization from p2 repository already. There is also some
rudimentary implementation of pom-first mode, but its usability outside
of m2e build context is probably limited. Many smaller features are
still missing and I am certain there are quite a few bugs too, but I
think overall tycho code is in reasonably good shape already.
Few words about relationship between maven and tycho. Tycho is not
morphing into maven, but it provides maven extensions and plugins that
enable maven to work with Eclipse/OSGi projects. Some of tycho
functionality, especially OSGi dependency injection, relies on maven
features only available in maven 3.0 which was very recently renamed
from 2.1. Since there is no maven 3.0 release yet, current tycho
distribution includes complete copy of maven 3.0-SNAPSHOT.
As for contributing to the project... well, this would be really awesome
. I think the best way to start is to try tycho and see what is missing
to support your projects and development workflow. Then we can work
together to implement missing features, fix bugs, etc. I have simple
demo that shows how to use tycho to build set of simple projects and
some user-level documentation. I will try to make this available later
today. I will also provide tycho dev env setup steps, so you can start
looking at the code if you want to. And tycho distribution is already
available from [1] (looks for the latest .zip file)
I hope it answers your questions, but feel free to ask more, especially
if something is not clear or does not make sense.
--
Regards,
Igor Fedorenko
[1]
http://repository.sonatype.org/service/local/repositories/eclipse-snapshots/content/org/codehaus/tycho/tycho-distribution/0.3.0-SNAPSHOT/
Alexandre Sauvé wrote:
Hi,
My company has been using Maven 1 for a couple of years now and we are
looking to make the transition over to the Maven 2 world (waiting for
the best opportunity)! The UI for most of our applications are RCP
based. The build process for the UI is using the PDE and is completely
autonomous from our middle tier build with Maven. We are hoping that
with the transition to Maven 2 there would be some new functionality to
allow for RCP/OSGi development. Unfortunately we have found that we may
not have waited long enough! There have been several options that we
have looked at to obtain bridge Maven and our Eclipse Development:
* *Building Eclipse Plugins with Maven 2
(http://www.eclipse.org/articles/article.php?file=Article-Eclipse-and-Maven2/index.html)*
In this articles the authors describe in detail how they
integrated Maven2 and Eclipse. One aspect of their approach that
I did like was how they made use of the manifest file to define
the dependencies for the project (similar to how Eclipse works);
however they need to use the 'Required-Bundle' tags rather than
the improved 'Import-Packages'. Though well documented this
approach wasn't favoured as it did not offer the Mojos re-built in
a repo (they just offer the code for the Mojos but they don't make
their Mojos available) and the article was written in 2006. The
company, Princeton software, was bought by IBM so it is hard to
get a hold of the developers for the project.
* *CodeHaus Maven PDE plugin
(http://mojo.codehaus.org/pde-maven-plugin)* This Mojo triggers
the PDE build from Maven. Though this approach would be fairly
straight forward in that the regular PDE mechanism can be used for
building the RCP application there are several drawbacks we see
related to the build occuring in 2 seperate build technologies:
PDE doesn't offer any way to easily integrate Maven 2 report
tooling into its build process (checkstyle, code coverage, ect.)
PDE is another technology for our developers to learn (more Ant
based build cycle)
* *Felix Bundle Plugin for Maven
(http://felix.apache.org/site/mavem-bundle-plugin-bnd.html)* This
Mojo is based on the BND tooling. In this approach all the
dependencies are specified in the POM and manifest is generated
during the package lifecycle in Maven. There are specific
commands to provide the 'Export-Package', 'Private-Package', etc.
However the BND tooling will analyze the byte code to determine
some information such as the 'Import-Packages'. Though this
tooling works well for generating OSGi bundles it does not
leverage the tooling available in Eclipse. Once you have your
plugin working with its dependencies in Eclipse you then need to
rework your POM to ensure that the manifest that is generated is
equivalent to that which you now have in Eclipse. This is not
always a trivial process. Given that limitation this is the
process that is favoured at the moment. Some pros about this
methodology:
+ What is nice about this approach is that everything is done in
Maven allowing you to now hook all the Maven reporting plugins.
+ Leverage Maven 2 Repo for your dependent bundles (note that your
bundles cannot be of the format of a jar within the bundle - they
have to be more like regular jars to be used by Maven)
+ Generate target platform in Maven
However after reading the article 'Jason Van Zyl Discusses Sonatype, The
Eclipse Foundation and Maven'
(http://www.infoq.com/news/2008/08/van-zyl-eclipse-sonatype-maven) we
believe that Tycho seems to be the up and coming solution to bridging
the world of OSGi and Maven. So I have done some research into Tycho
and have some questions:
* At the beginning of the Tycho development it was a set of plugins
to provide building with the PDE compiler (as it understands the
whole OSGi dependency/class loading issues), 'osgi-bundle'
lifecycle, generation of POM, etc. Now it seems to have morphed
into Maven 2.1? Is Tycho and M2Eclipse the basis of the
development for Maven 2.1?
* Will the new version be able to do everything with the manifest
that Maven 2.0 does with the POM? Through the manifest be able to
tell what dependencies are required? What if those dependencies
are only through Import-Packages (with a version to make life
easier)? Will the integration with the p2 enable M2Eclipse to
determine which bundles supply a given package and add the
required dependencie between the projects?
* Will the p2 integration be on top of the existing Maven repo or a
seperate repo to get bundles from?
* What is the timeline/gameplan for Tycho development at this point?
So as you can see we are really just starting out down this path. We
would be willing to help with development if we find an area that we can
contribute effectively into the project. However as of right now we
just want a starting point to start getting our projects configured to
using Tycho. Could you point us in the right direction? The ReadMe
file in the release now is the one for the Apache Maven, so it doesn't
really help with the configuration of a project using Tycho. Is it the
same configuration as before? Should we be using a different version
(previous version than 0.3.0)?
Thanks, Any help you can give would be appreciated!
Alex
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