Re: using perl in preinst script

[Rahul Amaram <amaramrahul@users.sourceforge.net>]

Hi Neil,
Thanks for the response. I didn't intend to work on this update as per 
my leisure. I greatly admire the Debian release team for the effort they 
put in, in trying to make Debian a great experience to the end users. As 
I've already told you, I am new and therefore didn't know of the 
deep-freeze of Squeeze. Or else I would have definitely worked on it 
earlier itself.

Anyway, coming back to the solution. This is what I plan to do. Kindly 
provide any necessary feedback.

1. Stop the server in preinst and if necessary copy the current 
configuration file to a temporary location.
2. In postinst, write python code to check if NSS directory service is 
being used (by parsing the configuration file) and if so take the 
appropriate action. Once this is done, delete the temporary copy of 
configuration file.

Also I believe for this, python needn't be added to Pre-Depends but only 
to Depends.

Pushing this script would make upgrade of calendarserver data 
directories seamless to end users who use NSS directory backend. This is 
the reason why I am so keen on pushing in this change so that the 
upgrade will cause the least inconvenience to end users.

If the above solution is acceptable, then I will work on it right away. 
If not, then I'll consider removing python from the preinst script 
altogether as rewriting it in perl/shell is a really huge task for me.

Cheers,
Rahul.

On Monday 27 December 2010 07:12 PM, Neil Williams wrote:
> On Mon, 27 Dec 2010 18:27:10 +0530
> Rahul Amaram<amaramrahul@users.sourceforge.net>  wrote:
>
>    
> > - Read the current caldavd.plist configuration file if it exists
> > - If NSS directory service is configured in caldavd.plist,
> >      
> ... then stop processing in the preinst at this point and set the config
> to not use NSS until configured.
>
>    
> > perform
> > some action on caldavd data directories for those NSS users and groups
> >      
> ... so do this in postinst then restart with the updated config.
>
>    
> > And this has to be done before the upgraded calendarserver runs for
> > the first time.
> >      
> Stop the server in the preinst (if not already stopped in the prerm of
> the old version) and don't start it until the postinst has finished
> doing the changes. Don't expect the server to be running between
> running the preinst and the postinst. Servers should be stopped before
> unpacking and restarted afterwards, in the postinst and after any
> config changes have been implemented.
>
>    
> > Hence running it in postinst is not an option.
> >      
> Actually, it probably is the only option.
>
> If necessary, consider changing the server so that it can run without
> needing this change. More commonly, ensure it is stopped in preinst
> and not started until after the postinst has finished.
>
>    
> > Anyway, keeping that apart, is there any chance that the upgraded
> > calendarserver could be pushed into squeeze if I make those changes
> > now?
> >      
> No. Squeeze is already in deep freeze. Only RC bug fixes are going to be
> accepted. It is too late to get non-RC bug fixes into Squeeze and the
> version in testing is not RC buggy (the version in unstable is
> potentially RC buggy). You'll just have to fix it in unstable and
> backport later.
>
>    
> > The reason being I am extremely occupied with other tasks
> >      
> It's too late - Debian releases take long enough as it is without
> waiting for everyone to have free time for their pet fixes to get in.
>
>    
> > and if
> > this package cannot be pushed into squeeze I'd rather work on it
> > after a while.
> >      
> You'll need to work on the package in unstable sooner rather than
> later. The version is unstable is buggy. Sooner or later you'll end up
> with a bug report that the preinst failed because python is not
> guaranteed to be configured when the preinst starts and that bug
> report would probably be RC.
>
> If you can't work on that now, pull the python preinst change out of
> the version in unstable and leave NSS configuration to the admin. Put
> something into README.Debian or News.
>
> Whatever you decide, the version in unstable does need to be fixed. You
> cannot expect a python preinst to actually work.
>
>