[pacman-dev] [RFC] alpmtrigger: triggering events after all packages got installed...

[Marc - A. Dahlhaus [ Administration | Westermann GmbH ]]

Am Freitag, den 11.09.2009, 11:18 +0200 schrieb Marc - A. Dahlhaus
[ Administration | Westermann GmbH ]:
> Hello List,
> 
> 
> currently i'm working on adding a trigger infrastructure to
> libaplm/pacman to get rid of workload during upgrades or installations
> that runs more than a single time.
> 
> Good examples for such jobs would be:
> 
> - depmod after module installations
> - mkinitramfs after module installations
> - catalog-updates for fonts or infopages
> etc...
> 
> 
> My current plan is to create a helper script called "alpmtrigger"
> wich handles the work of setting the triggers and executing the triggers
> after pacman is done with installation.
> 
> How would it work?
> Draft:
> 
> A package that adds a trigger to the system installs a trigger script
> that do all the work needed into a "/usr/share/pacman/alpmtrigger" dir.
> 
> inside of a packages install-helper we would call
> "alpmtrigger pkgtrigger" to set the trigger "pkgtrigger" active.
> alpmtrigger would do "touch /var/somewhere/alpmtrigger/pkgtrigger" wich
> would create the file if it not exists already.
> 
> A hook to execute "alpmtrigger" (without params?) would need to be added
> after the _alpm_run_chroot(root, "/sbin/ldconfig"); call in function
> _alpm_ldconfig inside of lib/libalpm/util.c to actualy scan the contents
> of /var/somewhere/alpmtrigger, and for each filename in it check
> if /usr/share/pacman/alpmtrigger/filename exists and if it is and is
> executable run the trigger. After the trigger is done and retuned
> without error, the file /var/somewhere/alpmtrigger/filename gets
> removed.
> 
> Any suggestions, comments or somebody else working on such a thing?

I took some time to rethink my first plan...

It would be more useful it the implementation of alpmtrigger gains the
ability to also execute a trigger currently.

alpmtrigger trigger
		Run the trigger now.
alpmtrigger {-a|--add} trigger
		Add the trigger to queue
alpmtrigger {-r|--remove} trigger
		Remove the trigger from queue
alpmtrigger [-x|--execute]
		Run all queued triggers

This way we would gain all the abilities required to trigger any task we
want at any point we want (by just adding the right thing to the right
spot in packages install helpers).

Marc