Hi, Farokh.
Most (all?) of the p2 core team are taking their vacations right now.  I
work on the UI for p2, so while I use the core API,  I don't know the exact
state of the underlying implementation and what limitations are there in
3.4 as well as those guys do.  So consider this answer as a bit of
hand-waving and later in the week someone can fill in more detail and your
follow-on questions.

>1)      Is the use case above a “reasonable” use case in the eyes of the
P2 project?
 The short answer is that the p2 architecture is exactly designed to
support scenarios like this.  One of the reasons for building a new
provisioning infrastructure was to support scenarios that have nothing to
do with Eclipse plug-ins and features, and handle support for native
installs, downloading and installing non-Java artifacts, etc. etc.

>2)      Is the use case above supported in P2 now?
Not without writing some code, and I'm not sure what else would have to be
done on the p2 side.  The focus for 3.4 was to be able to replace the
existing update manager, so much of our focus in that release was on the
simpler Eclipse install scenarios.  You may have read about p2's lack of
support for UM "install handlers."  For 3.4, we simply ran out of time to
cover the more advanced UM scenarios.  So while our architecture supports
custom installs at a much more granular level than UM did, what I describe
below may not have been tried yet, and there may be bugs/limitations/etc.
that we would have to fix for this to work.  (The core guys could provide
much more detail about where we are at exactly...)

The basic idea is that an installable unit (IU) can define "touchpoints"
that run at different phases of the install process.  p2 has implemented
touchpoints for Eclipse plug-in operations and some native file operations.
Third parties can register their own touchpoints.

In your scenario, you would define metadata representing your plug-in and
the native executable.  The user selects the IU that represents your
product and presses "Install...".  At this point, the user interacts with
the p2 UI (where any licenses would be approved and so forth).  This causes
the plug-in and installation file, and any other pieces necessary, to be
downloaded (by virtue of your metadata defining the pieces that are
required).  As your IU passes through the install phases, it goes through
several phases (download, install, configure).  At each of these phases,
the "touchpoints" can be run.  Your touchpoint would run the executable,
thus launching your UI.  When your install was completed, the touchpoint
would return and the rest of the p2 phases would continue until the user
was prompted for restart, etc.

There is some documentation on the existing touchpoint implementations at:
http://wiki.eclipse.org/Equinox_p2_Touchpoint_Instructions

>3)      If not, will it be supported very soon?
The 3.4.1 and 3.5 plans are not finalized.  The lack of install handlers is
a blocker for many products that otherwise want to adopt to p2.  So I would
expect something to happen early in the 3.5 cycle, but I can't promise
anything until we have plan.  Note that the API is all provisional in 3.4
and an important part of 3.5 is to work with a wide variety of install use
cases to make sure we handle them.

>4)      Should we abandon P2 and use the old update manager for the
foreseeable feature and count on P2 to support this use case BEFORE the old
update manager is deprecated?
If update manager install handlers support your needs, then I think it's
safe to assume that our touchpoint support would support your scenario
before UM is deprecated. I would imagine that we would either:
a) define a touchpoint that knows how to deal with UM install handlers in
some backward compatible way.  I'm not sure if this is possible or not,
depending on what assumptions were made by preexisting install handlers
with respect to the underlying file structure, etc.
b) define a specific migration guide that explains how to use touchpoint
actions to accomplish what was previously done in the install handler.

That said, if your product timeline allows you to work with us on this
scenario rather than waiting for it to be completed, it will help to ensure
that the evolving API meets your requirements.

I hope this helps...

susan




|---------+------------------------------->
|         |           "Farokh Morshed"    |
|         |           <[EMAIL PROTECTED]> |
|         |           Sent by:            |
|         |           equinox-dev-bounces@|
|         |           eclipse.org         |
|         |                               |
|         |                               |
|         |           08/04/2008 09:04 AM |
|         |           Please respond to   |
|         |           Equinox development |
|         |           mailing list        |
|---------+------------------------------->
  
>---------------------------------------------------------------------------------------------------------------------|
  |                                                                             
                                        |
  |       To:       <[email protected]>                                   
                                        |
  |       cc:                                                                   
                                        |
  |       Subject:  [equinox-dev] Does Eclipse support native installation 
scenarios?                                   |
  
>---------------------------------------------------------------------------------------------------------------------|




Our problems with adopting P2 is mounting.  I am starting to doubt whether
P2 in 3.4 is really ready for prime time or at least our use.

Use case:  We want the user to launch our plugin’s installation process by
simply clicking “Install…” in the Software Updates view.   This action
would download the plugin and a native installation executable (a window’s
MSI exe file).  Then, the native installation executable would be launched,
user interacts with the native installation process, and upon completion of
the native installation process the installation of the plugin proceeds.
If something goes wrong during the native installation, or user simply
changes his mind and cancels, we don’t want the plugin to be installed at
all.

But it appears that P2 has no way for us to launch the native installation
executable.

We have also thought about launching our native installation executable
upon first use of the plugin.  We certainly would not want to do this in
the plugin’s start method.  That would violate the etiquette that plugin
start method take a very long time.  So, we would leave this initialization
for after the start method, to the actual use of our plugin.  But, what if
the installation failed.  What if the user changed his mind and decided not
to install at all.  How do we tell Eclipse that this plugin is “dormant”
and should be uninstalled by the user, you know, something similar to how
Eclipse behaves after a plugin start method has raised an exception.  Looks
like we cannot just call the plugin’s stop method, the Plugin’s stop method
comment says “Clients must never explicitly call this method”.

I feel like we are between a rock and a hard-place, or totally missing
something.

My questions are:
      1)      Is the use case above a “reasonable” use case in the eyes of
      the P2 project?
      2)      Is the use case above supported in P2 now?
      3)      If not, will it be supported very soon?
      4)      Should we abandon P2 and use the old update manager for the
      foreseeable feature and count on P2 to support this use case BEFORE
      the old update manager is deprecated?

By the way, we will always have this native installer.  Eliminating the
native installation is not an option for us.

If this mailing list is not the proper place to discuss this matter, PLEASE
tell us so.  Thank you.

farokh _______________________________________________
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