[p2-dev] Re: [cross-project-issues-dev] Question concerning feature upda

[Nick Boldt <nickboldt@xxxxxxxxx>]

Sorry, should have been more clear. JBoss Tools is *NOT* part of Helios. 
We're downstream from Web Tools, TPTP, BIRT & m2eclipse.

I'm only pointing out what we do from an ease of use / maintenance point 
of view, because these URLs are not even seen until AFTER the features 
are installed, and because by providing them they stick around forever 
(and must therefore be maintained too).

Since the platform provides the URL for Helios, and since you're in 
Helios, there's no reason to provide the same information again.

Even if you wanted to force a particular feature to believe that it 
should be updated from some other site than whence it came, I'm fairly 
certain that if you have multiple update sites listed in Eclipse, and 
each site contains a given feature update on them (eg., Helios official 
one, Your Project official one, someone else's patched version), p2 will 
read all the enabled sites and present you the latest version, 
regardless of what the installed feature's feature.xml says is its One 
True Update URL. I don't believe p2 has a notion of site or package 
version "priority", a la Debian's apt-get [1].

[1]http://www.debian.org/doc/manuals/apt-howto/ch-apt-get.en.html#s-pin

So if you wanted to install an update to the Foo Feature from the 
official Helios 1.0.0 version to 1.0.1.patched.by.someone.else, you'd 
have to first disable the Helios and project sites, then run an update 
from that single site. Or, if using install instead of update, you could 
uncheck the "Contact all update sites" box so only the single site would 
be seen.

Copying the p2-dev list for comment in case I'm way off kilter here.

Nick

On 04/22/2010 09:13 AM, Eric Gwin wrote:
> Nick,
>
> So the discovery and update URLs aren't required for Helios? I only
> included them because it seemed they were for Galileo, and there was
> some policy regarding where they should point - something like: update
> to Galileo P2, and discovery to project update but I cannot find the
> specifics.
>
> If these are only utilized by the install, then it sounds like it would
> be completely unused for an RT library (target platform), so I should
> probably simply drop them as well.
>
> -Eric
>
> Nick Boldt wrote:
> > We recently dropped both <update> and <discovery> from our features in
> > JBoss Tools, because in order to have the user see these URLs, they
> > have to first install the feature (from a mirror site or zip), thus
> > negating the need to advertise where the feature came from.
> >
> > <discovery> gets added *when the feature is fully installed* as a
> > _disabled_ update site
> >
> > <update> gets added *when the feature is fully installed* as an
> > _enabled_ update site; if it's the same URL as the site from which the
> > feature was installed, it's therefore redundant.
> >
> > A better approach, if you want to force the user to get p2 repos added
> > as associate sites *when reading the repo*, rather than *after
> > installing the feature*, then read this:
> >
> > http://divby0.blogspot.com/2010/03/athena-p2-repos-w-associate-sites.html
> >
> > The actual magic is simply to append some information into the
> > content.xml file - see "add.associate.sites" task in
> > http://dev.eclipse.org/viewcvs/index.cgi/org.eclipse.dash/athena/org.eclipse.dash.commonbuilder/org.eclipse.dash.common.releng/tools/scripts/buildAllHelper.xml?root=Technology_Project&view=markup.
> >
> >
> > Nick
> >
> > On 04/20/2010 10:56 AM, Eric Gwin wrote:
> > > Hi,
> > >
> > > I'd like to ask a few questions to the group regarding P2 repo and
> > > feature generation:
> > >
> > > What are the expected values for the repo URLs used in the features?
> > > <url>
> > > <update label="%updateSiteName" url="%primaryUpdateURL"/>
> > > <discovery label="%secondaryUpdateSiteName" url="%secondaryUpdateURL"/>
> > > </url>
> > > From experience it can be any valid URL, and specifically a valid
> > > update site. I'm asking what I should
> > > be putting in there since I am only generating the features once and the
> > > repos are mirrored from our
> > > project update site(s) to our simultaneous release update site.

--
Nick Boldt :: http://nick.divbyzero.com
Release Engineer :: Eclipse Modeling & Dash Athena