[xwiki-dev] [Proposal] Plugins and xwiki distributions

[Vincent Massol]

> -----Original Message-----
> From: Ludovic Dubost [mailto:ludovic at xwiki.com]
> Sent: samedi 14 octobre 2006 15:22
> To: xwiki-dev at objectweb.org
> Subject: Re: [xwiki-dev] [Proposal] Plugins and xwiki distributions
> 
> jeremi joslin a écrit :
> > Hi Vincent,
> > thanks for your work.
> >
> > On 10/14/06, Vincent Massol <vincent at massol.net> wrote:
> >> Hi,
> >>
> >> I'd like to propose the following:
> >>
> >> 1) We create a single trunk/, branches/ and tags/ for plugins
> instead
> >> of having one per plugin which is a maintenance nightmare. This is
> >> what we're doing for Maven and it seems to be working fine. See
> >> http://svn.apache.org/repos/asf/maven/
> > If you think it's better, I agree. But how we do when we want to
> > release a plugin? All the plugins have to be stable at the same time?
> >
> Would it make sense for some bug plugins (like Lucene search) to have
> their own trunk/branches/tags ?

Sure but this can be done with a single branches/ and tags/ dirs. See
https://svn.apache.org/repos/asf/maven/plugins/

> >> 2) We move all plugins from core/main/src/java/c/x/w/plugin/* to
> >> xwiki/xwiki-plugins/trunk/*. That's provided there's no direct link
> >> between the core and the specific plugins. If there are then they'll
> >> need to be decoupled, possibly by introducing a components/
> directory
> >> of components (which BTW could be used as the parent directory for
> >> hosting components if/when we decide to move to using a
> >> component-based architectire (OSGI, etc).
> > Yes, be carefull with the plugin with dependencies inside the code
> > like the upload plugin. A solution, could be to change it to
> > component, and doing a plugin to access to the functions of this
> > component. Some plugins have dependencies between them also. for
> > exemple in the GELC project, some the plugins are depends on the
> > others. I think some plugins(actually on the core) are depend on
> > others.
> >
> Does it mean components and plugins are different thing  ? I tend to
> believe everything is a plugin. It's just that some plugins provide
> their own component API and implementation, some plugin implement some
> of the XWiki plugin hooks and some plugins do both.

There are some differences I think. A plugin is optional and doesn't have to
be installed for XWiki to work whereas a component is mandatory and is not
seen by the end users. A user will not be offered the choice to install a
component. He'll only be offered the ability to install plugins.

Other difference is that plugins can use components to implement their logic
whereas plugins should not use/call other plugins.

I guess they could be called the same but that would be confusing.

I like Maven's organization:

* components: https://svn.apache.org/repos/asf/maven/components/trunk/
* plugins: https://svn.apache.org/repos/asf/maven/plugins/trunk/

Maybe it's only a terminology issue but I think it makes thing clearer to
name them differently and locate them in different places in the directory
structure.

> An example of a module being only a component would be the Store. An
> example of a module being only a plugin would be  the SVGPlugin. An
> example of a module being both would be the FileUpload plugin.
> Plugins/Components will need to be extended to add hooks to the XWiki
> Action engine (currently based on struts). This would allow to
> transform more code that the core depends on to plugins/components.
> 
> Maybe a module called "core-plugins" could make sense to package some
> mandatory plugin for XWiki to actually work at least as a wiki.
> 
> Indeed we should prepare to implement a standard based component
> architecture.
> 
> >> 3) Each plugin build will result in a plugin jar and we add some or
> >> all of those jars to the distributions. As there's currently no
> >> online plugin downloading mechanisl we may need several
> >> distributions: a minimal one without any plugin, one with "core"
> >> plugins and one with all plugins. Or we could choose to have only 2:
> >> one without plugins and one with all plugins.
> >
> > I prefer the first solution, but with something a little bit
> > different, we distribute the core with the minimum required plugins,
> > and we create a repository with all the jar of the plugin (as ibilio
> > for maven), and a package with all the official plugins.
> >
> If it's possible to minimize the amount of jar that would be great,
> especially for components.

All components would be included in the xwiki core distribution IMO.

> It could be a pain to have a jar for API and a jar for implementation,
> especially when XWiki core depends on that API. In this case it could
> be better to leave it in the core.
> The use of a core-plugins module could allow to reduce the amount of
> jars.

Thanks
-Vincent






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