How to pacman -Sy by hand, or against only a single repo? [SOLVED]

Question

I've written a wrapper for makepkg that builds my packages and adds them to my local custom repo. If I give the wrapper a -i flag, I want to then install them from the repo. I suppose I could just use pacman -U, but I prefer to use yaourt -S local_repo/package_name=desired_version. To do this, though, I have to synch my pacman lib db against the newly updated local_repo. Currently I'm just doing a pacman -Sy to do that. Downside is that hits all the other repos too. Often I find myself building and rebuilding and reinstalling a package multiple times as I tweak the PKGBUILD. Repeatedly synching against all the repos is bad for me (few extra seconds every cycle) and bad for the repos.
What I need is a way to synch against only my local_repo. I can't figure out how to do that using any pacman cmd-line switch. The format of the repo file looks very simple, so I tried doing this manually:
sudo tar -xzf /path/to/local_repo/local_repo.db.tar.gz -C /var/lib/pacman/sync/local_repo
stat --printf "%X" /path/to/local_repo/local_repo.db.tar.gz | sudo tee /var/lib/pacman/sync/local_repo/.lastupdate > /dev/null
But pacman still seems not to notice the changes. E.g. if I do pacman -Si local_repo/new_package, I get a report of the previous package version, not the newly added one.
Is there any way to synch just my local repo, either using pacman or by hand?
Last edited by Profjim (2009-07-31 21:14:34)

Answer 1

You're right, that works.  As happens too often, I was making things more difficult than they needed to be...
EDIT: it works sometimes, and sometimes doesn't. I still can't figure out what determines the difference...
If you untar on top of a directory, any existing directories (at least at the top level) that don't exist in the archive will be left there, not removed. But this is fine for my purposes. I can wait until the next full pacman sync to delete them.
And the problem of I-dont-wanna-untar-the-old-stuff-too can be solved by doing:
sudo tar -xzvf "$PKGDEST/$REPONAME.db.tar.gz" --after-date="@$(cat /var/lib/pacman/sync/$REPONAME/.lastupdate)" -C /var/lib/pacman/sync/$REPONAME
That is, we use the sync dir's existing .lastupdate file to give us a date (in Unix epoch format, which tar needs to see as "@12234556"), and we tell tar just to extract the files modified after that date. I can tell from the -v output that this is working properly.
But it's still a mystery why sometimes this works and sometimes doesn't...
# ...add new package version to local_repo, then...
sudo repo-add path/to/local_repo.db.tar.gz path/to/new/package
# untar local_repo.db.tar.gz on top of /var/lib/pacman/sync/local_repo, as above, then...
sudo pacman -S local_repo/new_package=new_version
Last edited by Profjim (2009-07-31 21:00:56)