[AG-DEV] Re: Location of AG config files
Christoph Willing
c.willing at uq.edu.au
Wed Sep 17 01:43:32 CDT 2008
Well, I found that this is partly the packager's problem rather than
a package system problem - a badly placed 'rm -rf /etc/
AccessGrid3' (in the prerm script) meant that files were not able to
be saved during upgrades. However, moving this cleanup to the postrm
script doesn't help other applications using that area (like
additional NodeServices).
Also, as already mentioned, its somewhat surprising to find things
like shared application code under /etc - I would add node services
with executables to the list of unexpected finds there. Therefore I
still like the idea of moving some of the stuff from /etc/AccessGrid3
over to /usr/share/AccessGrid3.
I sent some patches to Tom which implement this separation and in the
meantime I've have made a set of AG3.2 packages which include the
patches for Ubuntu Intrepid Ibex. Since that is not released yet,
very few people would be using it, thereby limiting any possible
negative effects. Also, anyone trying out the patched AG toolkit on
intrepid would not be in a production setting anyway and it gives me
a chance to test with a live system.
I could make similar packages for lenny, which is also unreleased,
although in this case I've had packages available for lenny for a
while now and know that some people are using them already. I'm
unsure whether its fair to inflict test code on them ...
Any comments, further ideas on this?
chris
On 15/09/2008, at 7:46 PM, Tobias Schiebeck wrote:
> Hi,
>
> On Sat, 2008-09-13 at 14:50 +1000, Christoph Willing wrote:
>> On 12/09/2008, at 5:41 PM, Tobias Schiebeck wrote:
>>
>>> Hi,
>>>
>>> Beeing a Debian user for some years now, I know that Debian has
>>> sometimes strange ideas how to package things. On the other hand
>>> I was
>>> slightly surprised to find "code" such as the SharedPresentation
>>> implementation under /etc . IMHO /etc is the place for config files
>>> and
>>> thats what I think Debian is trying to enforce (which I don't
>>> think is
>>> the right thing to do but ...)
>>>
>>> On Thu, 2008-09-11 at 07:55 -0500, Thomas D. Uram wrote:
>>>> Chris:
>>>>
>>>> What's the chance that a future change will also impact files under
>>>> /usr/share, requiring another adjustment? Is there any guidance
>>>> from
>>>> the debian/ubuntu community about how to adjust, or where such
>>>> files
>>>> should be placed?
>>>>> (One way around this would be to create a single mega-package of
>>>>> AG &
>>>>> related service packages, but I feel it would be an
>>>>> unsatisfying, if
>>>>> not "wrong", solution)
>>>> I agree that this is not the right way to go.
>>>
>>> I think /usr/share is where the NodeServices and other "code"
>>> should be
>>> placed and should be fairly safe from changes. The pure
>>> configuration
>>> files such as the nodeConfig could stay under /etc as it would be
>>> recreated if it isn't there, and /etc is the place where people
>>> look for
>>> these general configuration stuff.
>>
>>
>> I agree that this is the correct way to go.
>>
>> However splitting these files into separate locations entails more
>> work to implement compared with having them all in /etc or all in /
>> usr/share - having them all in one place means just a single line of
>> code needs to be changed (the definition of AGTkBasePath).
>>
>
> I think this split up is a long term solution. In the short term a
> move
> to /usr/share should be safe as we can declare the configuration files
> as software essentials ;-).
>
>> If we now have a separate location for some of the files (I suggest
>> the Services, NodeServices and SharedApplications directories), then
>> we'd need not just an additional variable defining the new location,
>> but also changes to any current code which assumes the old locations.
>> For instance, convenience functions like GetSharedAppDir() themselves
>> call GetBaseDir() which would now return the wrong location;
>> something to replace GetBaseDir() is needed in all these cases.
>>
>>
>> If we decide to go ahead with something like this, the next question
>> is who will implement it? I'm prepared to do it but the changes touch
>> on reasonably fundamental bits of AG internals so perhaps it is best
>> left to Tom ... ?
>>
>> Either way, Debian Lenny is currently frozen in the lead up to being
>> released. It would be good to have any AG changes fully in place by
>> the time Lenny is released.
>> Similarly, Ubuntu 8.10 is due in October.
>
> I don't think there is a need to rush things trough to change internal
> structure for these a move should solve the problems of the file
> deletion
>
> Tobias
>>
>>>> On 9/8/08 6:37 PM, Christoph Willing wrote:
>>>>> Tom,
>>>>>
>>>>> There is a problem with the Debian & Ubuntu AG packages. The
>>>>> revamped
>>>>> build tool mechanisms introduced early this year to accommodate
>>>>> multiple python versions on the same machine has an unfortunate
>>>>> side
>>>>> effect; anything under /etc is considered to be owned by a
>>>>> particular
>>>>> package and is removed completely during upgrades or
>>>>> reinstallations,
>>>>> regardless of whether another package may be using the same area.
>>>>>
>>>>> In the case of the AG installation, a number of configuration
>>>>> files
>>>>> are kept in directories under /etc/AccessGrid3. In particular,
>>>>> /etc/AccessGrid3/NodeServices normally contains the standard
>>>>> Audio &
>>>>> Video Services. However other packages may want to install
>>>>> services
>>>>> there too e.g. vpcscreen, aghdvic. Initial installation of these
>>>>> packages works OK but if the AG package is reinstalled or
>>>>> upgraded,
>>>>> the additional services are also removed.
>>>>>
>>>>> (One way around this would be to create a single mega-package of
>>>>> AG &
>>>>> related service packages, but I feel it would be an
>>>>> unsatisfying, if
>>>>> not "wrong", solution)
>>>>>
>>>>> This (new) unwanted behaviour occurs because of the special
>>>>> treatment
>>>>> given to files/directories under /etc, so an solution is to use a
>>>>> different location. I have done some testing using
>>>>> /usr/share/AccessGrid3 instead of /etc/AccessGrid3 as a
>>>>> location for
>>>>> the config files. With this new location, any number of
>>>>> installations,
>>>>> reinstallations etc. of the AG & related packages can now be
>>>>> performed without any interference to each other. Introducing the
>>>>> new
>>>>> location is trivial - a single line patch to the toolkit code
>>>>> itself,
>>>>> as well as a single line change in the packaging script of each
>>>>> affected package (accessgrid3.x, vpcscreen, aghdvic, etc.)
>>>>>
>>>>>
>>>>> Since this is a Debian & Ubuntu specific problem, I don't expect
>>>>> that
>>>>> relocating /etc/AccessGrid3 needs to apply to all distributions
>>>>> (although it may be worth considering). However before I
>>>>> release any
>>>>> packages with the new file layout, do you have strong feelings
>>>>> about
>>>>> the proposed solution - or alternative solutions?
>>>>>
>>>>> I've cc'd to AG-DEV in case someone more conversant with Debian/
>>>>> Ubuntu
>>>>> Policies & packaging practices can offer advice; please chime in
>>>>> - I'm
>>>>> just a part-timer in this area and I'm keen to receive
>>>>> suggestions.
>>>>>
>>>>>
>>>>>
>>>>> chris
>>>>>
>>>>>
>>>>> Christoph Willing +617 3365 8350
>>>>> QCIF Access Grid Manager
>>>>> University of Queensland
>>> --
>>> --------------------------------------------------------------------
>>> -
>>> Tobias Schiebeck
>>> tobias.schiebeck at manchester.ac.uk
>>> Research Computing Services http://
>>> www.rcs.manchester.ac.uk
>>> The University of Manchester tel: (+44)
>>> 161-275-0601
>>> --------------------------------------------------------------------
>>> -
>>>
>>>
>>
>> Christoph Willing +617 3365 8350
>> QCIF Access Grid Manager
>> University of Queensland
>>
> --
> ---------------------------------------------------------------------
> Tobias Schiebeck tobias.schiebeck at manchester.ac.uk
> Research Computing Services http://www.rcs.manchester.ac.uk
> The University of Manchester tel: (+44) 161-275-0601
> ---------------------------------------------------------------------
>
>
Christoph Willing +617 3365 8350
QCIF Access Grid Manager
University of Queensland
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