[Python-Dev] Issues with Py3.1's new ipaddr
mike at pennington.net
Wed Jun 3 10:42:47 CEST 2009
Raymond solicited a comment from me about the design of ipaddr. By way
of full disclosure, I have a small competing project called pynet.
That said, I test drove ipaddr for about 30 minutes and so far like the
big-picture API design quite a bit. I'll specifically address Clay's
concern about hosts vs networks, because this issue is important to me;
I've been in the network engineering field for over 15 years, worked on
Cisco's product development team, and held a CCIE (consider it the
equivalent of a CPA for network engineers) for 10 years...
Clay seems to object to ipaddr's IP object because it is not the same as
the object model used in the BSD ip stack. Indeed, I'm one of the
raving fans of what BSD has done for the quality of ip networking, but
let's also consider their requirements. BSD must approach ip networking
from a host perspective, it is the consumer of individual IP packets and
their payloads. ipaddr's whole point of existence is really driven
towards the manipulation of potentially massive lists of ip addresses.
This is no small difference in requirements, and I believe ipaddr's
different approach makes their code much simpler for the tasks it needs
to do. Incorporating host addresses as a special case of a /32 IPv4
network or /128 IPv6 network makes a lot of sense to me, in fact, I also
chose this same object model. Perl's NetAddr::IP does this too, it is
considered the gold standard for perl's address manipulation module.
Whether python includes ipaddr now, later, or uses another module
entirely does not bother me. Whatever is included should have a very
stable API, and major bugs should be worked out. Documentation should
be good enough for the average consumer, and if anything this is where
ipaddr to be lacking a bit.
I hope that python does include something to manipulate IPv4 and IPv6
address blocks in the future, since this is a big hole is python's
batteries-included philosophy. However, I'd need more time at the wheel
of ipaddr before I could comment whether this truly is ready for
inclusion in stdlib.
All the best,
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