Re: 4.5 features: Automagically export package metadata

[Jeff Johnson]

On Jun 8, 2007, at 6:29 PM, Michael Jennings wrote:

On Friday, 08 June 2007, at 18:09:07 (-0400),
Jeff Johnson wrote:

Direct access to an rpmdb requires locking, and shared read locks
are a DoS for exclusive write locks, and vice versa, no matter what.

So custom automagic exports avoid the locking issues associated with
direct access to an rpmdb. Note that other locking issues are
possibly introduced because the export/update may have issues with
whatever some application desires, but at least the locking is finer
grained, with less contention, than having every application
competing for rpmdb access.

Which would also be true for the daemon.  Obviously it wouldn't be
able to have permanent locks on the DB, but something with
fam/imon/poll to watch for rpmdb changes, lock, update, unlock...would
that be reasonable?


A read only file system presentation based on automagically (and  
synchronously)
exported custom data is rather easy to do. The directory mtime that  
contains the
export can be stamped when there is a change, so fam/imon/poll have a  
simple
event  trigger. Only the  containing directory would need to be checked.

But fam/imon/poll are perhaps overkill if all you want is to display  
some readonly
metadata in a file system like hierarchical format. The automagic  
export in
current rpm installs/erases (and exports) exactly when the package is  
registered
in an rpmdb.

Write operations for a file system presentation to trigger, say, an  
install/upgrade
would be slightly trickier. Likely the easiest implementation would be
     echo "/path/to/my/pkg*.rpm" > /rpm/install
as a means to install/upgrade a package, including all necessary  
dependencies of course.

Assuming a /rpm mounted pseudo file system based on FUSE.

 So what's nutty about using del.icio.us instead of rpmfind.net?

I'm all for using tags as a replacement for Group: which went up a
creek the moment other distros stopped giving two hoots about
/usr/share/doc/rpm-4*/GROUPS.

Are you also advocating using del.icio.us as an rpm search engine?
I'm not sure how that would be better than updating rpmfind.net to use
tags, as it is a niche engine where del.icio.us (which I'm *really*
starting to hate typing, BTW :P) is all-purpose.


Not advocating, I'll leave that to the ix86/linux puppies and the  
Debian Borg.

But del.icio.us allows personal tagging, and the signal-to-noise  
ratio for
del.icio.us social tags is higher (and easier to believe) than any other
hierarchical tag format/taxonomy for content (in this case packages)
that I'm aware of.

Yah, took me a while to figger how to type del.icio.us instead of  
deli.cio.us.
I'm mostly there now.

A delicious search on "rpm" revealed that rpm is related to "music."
Neato. :-)


Don't start ;-) I dearly wish to storm Redmond and hijack the *.rpm  
mime type
from Real Audio some day.

73 de Jeff
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