Hello again,
I am continuing with some experiments along the directions that Jeff gave me. I
encountered several problems for which I cannot find an explanation. For
example, I tried to update the product after incrementing its version in the
repository. The update failed again because it lists among its requirements a
tooling configuration unit which is a singleton. It looks quite simple:
<unit id='tooling<product name>.configuration' version='<product version>'>
<provides size='1'>
<provided namespace='org.eclipse.equinox.p2.iu' name='tooling<product
name>.configuration' version='<product version>'/>
</provides>
<touchpoint id='null' version='0.0.0'/>
</unit>
Note that this is generated by the product publisher and cannot be avoided. I
don't have any idea what the purpose of such a basic unit could be but being a
singleton and a requirement of the product, it stops the update of the whole
product because there is already an IU installed with the same name on the
system (actual message from p2 director says "Only one of the following can be
installed at once", concerning this IU).
Can anybody tell me why is this configuration unit created at all on publishing
?
In general, I am very surprised to see how many problems I encounter to
implement a "simple" product update given the fact that p2 supports updates of
features and bundles out of the box. So far, the most direct approaches I tried
failed completely:
- If I try to update, preserving the same product version (as it is
fixed in the .product descriptor), it fails because of conflicting versions of
the requirements.
- If I try to update with an increased version of the product, then
the singleton configuration unit stops me.
So it seems that my initial concept how the product update should be done is
wrong. But then how new versions of products are supposed to be shipped to
customers to be consumed immediately by p2 ? How are the customers supposed to
perform updates of the whole product (not by individual bundles and features) ?
Best regards,
Shenny
From: [email protected] [mailto:[email protected]] On Behalf
Of Jeff McAffer
Sent: Friday, September 24, 2010 4:36 AM
To: P2 developer discussions
Subject: Re: [p2-dev] Product publishing and product update
There are a couple sides to this. One is that if you have Product X v
1.2.3.20100923, that should mean something. If you allow ranges as described,
then two users installing X 1.2.3.20100923 may not get the same actual software
installed. Variation is introduced for example, if user 1 has access to a
different set of repos than user 2 or there is a network error for user 1 but
not user 2 or the single repo changed between when user 1 and user 2 did their
install.
Of course, these behaviours *could* also be exactly what you want but certainly
some folks free at this non-determinism as a support nightmare.
Anyway, looking at features, they allow for things to be *included* or
*required*. Included things have exact version ranges while required things
have, generally, wider ranges. Traditionally the notion was that on install,
the things *included* by the feature were installed whereas the things
*required* merely had to be there. Early update manager didn't even help you
find/get/install the required things. That was goofy so we provided a means
for users to say "yeah, get the required stuff also". Now with p2 we do this
automatically without involving the user. So much for context...
It would be reasonable to allow ranges on product content but it would also
force the product designer to be very aware of the consequences pointed out at
the beginning of this message. I honestly don't know what people would do
naturally or what guidance we could/should give them (e.g., what's the
default?).
Back to your original topic, there is also the possibility of producing new
versions of your product that identify the new versions of the components.
Product production and distribution in p2 is very light weight and users would
see this as incoming new versions of the product (that they know about) vs
changes to random components (that they may well not even know exist). What
would you say as the user of some banking product if told that there was a new
version of EMF? "WFT?!"
Scenarios vary. If that does not work for you, you can insulate your product
by making it consist of one feature. In that feature, *require* everything that
you want to be updatable, include the stuff you want to be fixed (or put this
stuff directly in the product). The product will be bound to the one version
of your container feature and the container feature can use ranges. Beware the
problems outlined above with non-determinism. Note that you can also usethe
p2.inf file to do this. Andew Niefer did a couple blog posts on this a while
ago
http://aniefer.blogspot.com/2009/07/composing-and-updating-custom-eclipse.html
http://aniefer.blogspot.com/2009/07/composing-and-updating-custom-eclipse.html
Good luck
Jeff
On 2010-09-23, at 12:13 PM, Yousouf, Shenol wrote:
Hi all,
I noticed that product publishing always sets requirements for a fixed version
of the contained bundles/features, i.e. the defined range has its lower and
upper boundaries equal like this:
<required namespace="org.eclipse.equinox.p2.iu"
name="TestBundle"range="[1.0.0.201009171510,1.0.0.201009171510]" />
while I need something like this:
<required namespace="org.eclipse.equinox.p2.iu"
name="TestBundle"range="[1.0.0.201009171510,2.0.0)" />
or even this:
<required namespace="org.eclipse.equinox.p2.iu" name="TestBundle"
range="1.0.0.201009171510" /> (which means "any version > 1.0.0.201009171510")
The .product file format does not support a way to specify a range for its
components, only an attribute for a fixed version. The product publisher also
has no notion how to generate version ranges - it simply sets the range
boundaries equal to the component version (see method
AbstractPublisherAction.createIURequirements() for reference). So far, I cannot
find a way how to workaround this issue and in my opinion it as a limitation of
the product definition concept.
Why is this so important ? The use case is like this:
I am developing a product consisting of several components which is getting
published on an update site on a regular basis. The components receive frequent
updates in the p2 repository and their versions are incremented which is
reflected in the requirements of the published product. However, once I install
this product, I cannot apply updates to the system any more. The updates are
refused because version ranges of the requirements for the installed and the
updated products do not intersect which seems to make them incompatible.
This wouldn't be the case if it was possible to define open ranges in the
product file. For example, the installed product would require a specific
component in version range [1.0.0, 2.0.0) while its new version would require
it in the range [1.1.0, 2.0.0). This would allow the update to pass because
obviously range [1.1.0, 2.0.0) is compatible with (falls into) range [1.0.0,
2.0.0). The way they are generated now is [1.0.0, 1.0.0] for the old product
and [1.1.0,1.1.0] for the new one. Since these two ranges do not intersect, the
update is not possible.
In short, I have two issues and hope to receive some advice from you how to
address them:
* Is it possible to define a product with extended version ranges of its
components ?
* What makes product versions compatible for update ? Why changed version
requirements, which come as a natural result of the publishing process, do not
allow the product to get updated to the higher version of its included
components ?
Best regards,
Shenny
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