Re: [Libvir] generator.py -- why?
On Mon, Aug 28, 2006 at 11:53:09PM -0400, pvetere(a)redhat.com wrote:
Hi all. So, I found a bug in the python bindings that I'd really
like to fix,
but when I sat down to do so I quickly found myself mired in a swampy mess of
code generation: generator.py. :-) Now, I feel compelled to ask -- why don't
we just have a static libvirt.py file that is WYSIWYG? The generator.py
program alone is longer than the file it generates, and having a static file
would not only make the code easier to read, but would also make bug fixing
much simpler. But, I'm sure there's got to be a good reason for it. :-)
Here's a program that produces the bug I tried to address:
import libvirt
def get_domain(dom_name):
conn = libvirt.openReadOnly(None)
domain = conn.lookupByName(dom_name)
return domain
d = get_domain("mydomain")
print d.info()
This is a fairly typical "factory" pattern I could imagine people using. The
This is a also a very bad pattern to use. Not only is opening a new connection
a fairly heavyweight opertion - it has to connect to xenstore, xend, and fork
fork the proxy server. Now if each time to your get_domain the domain object
returned is associated with a different connection object. This bypasseses the
caching of domain object instances which is done internal to libvirt, degrading
performance still further.
Regards,
Dan.
--
|=- Red Hat, Engineering, Emerging Technologies, Boston. +1 978 392 2496 -=|
|=- Perl modules: http://search.cpan.org/~danberr/ -=|
|=- Projects: http://freshmeat.net/~danielpb/ -=|
|=- GnuPG: 7D3B9505 F3C9 553F A1DA 4AC2 5648 23C1 B3DF F742 7D3B 9505 -=|