nova team mailing list archive

[Vishvananda Ishaya <vishvananda@xxxxxxxxx>]

One vote for sticking with Twisted here.

We've had more issues dealing with async processes, threading, and logging
then any other part of the Nova system.  After a lot of late debugging
nights we actually have a system that works and handles these things well.
 I think there is a hidden cost in switching is redoing much of this effort
and dealing with instability while we get the kinks worked out.  I would
prefer not to go through that process again :)

Debugging these issues is challenging and so is writing tests.  I would
suggest that if we are going to make a major switch like this, we spend some
time banging away at test coverage so that we can feel more confident that
we aren't breaking the sytem.

Vish

On Fri, Jul 30, 2010 at 8:42 AM, Eric Day <eday@xxxxxxxxxxxx> wrote:

> On Fri, Jul 30, 2010 at 10:51:06AM -0400, Jay Pipes wrote:
> > FWIW, I'm perfectly happy to work with either. :)
>
> Same here, and I do see Soren's point about having a fairly large
> protocol suite ready to go. On the other hand, Eventlet does
> provide module patching to make existing modules non-blocking (see
> http://eventlet.net/doc/basic_usage.html#patching-functions). Can
> anyone speak to how well this works? My main concern, as
> Michael pointed out, is the ease of use and ability to get others
> involved. I've talked with other programmers in the past who had the
> same reaction to Twisted. We need to think about the longevity of
> the project and which choices will keep the barrier to entry as low
> as possible while still meeting our needs.
>
> -Eric
>
> >
> > -jay
> >
> > On Fri, Jul 30, 2010 at 8:25 AM, Michael Gundlach
> > <michael.gundlach@xxxxxxxxxxxxx> wrote:
> > > On Thu, Jul 29, 2010 at 5:42 PM, Soren Hansen <
> soren.hansen@xxxxxxxxxxxxx>
> > > wrote:
> > >>
> > >> On Thu, Jul 29, 2010 at 03:47:46PM -0500, Michael Gundlach wrote:
> > >> > +1 for Eventlet for the reasons already stated.  Simpler code often
> > >> > translates to fewer bugs and faster development, and I expect that
> > >> > working with Eventlet will also mean more people who are interested
> in
> > >> > contributing to OpenStack.
> > >>
> > >> Really? You think there's more of a community around eventlet than
> > >> Twisted?
> > >
> > > No info there.  I have not used Eventlet or Twisted in the past, and am
> > > giving the perspective of an outsider considering working with the
> project.
> > >  I had two offers earlier this year -- one to work at a company solving
> a
> > > large scaling problem on a Twisted system, and one to work solving a
> large
> > > scaling problem working in Eventlet.  They were pretty similar offers
> so it
> > > came down largely to choosing the technology I'd want to work with.
> > > When I researched Twisted, I read or got the impression that:
> > > - it had a "near-vertical learning curve"
> > > - it was named Twisted for a reason -- that it's hard to think the way
> > > Twisted needs you to think
> > > - its libraries were a morass (the homepage talks about having two web
> > > frameworks and it's not clear which one to choose)
> > > When I researched Eventlet, I read or got the impression that:
> > > - it is clean and intuitive to code in
> > > - it was the thing that came along after Twisted to solve the problem
> in a
> > > better way
> > > - momentum was gaining around it while Twisted was losing momentum
> > > I took the Eventlet job with Rackspace (having mistakenly understood
> during
> > > interviews that Rackspace was for-sure migrating to Eventlet :) )
> because
> > > what I had been able to find out made Twisted look unappetizing and
> Eventlet
> > > look great.
> > > I would imagine that my experience is typical -- a shallow review of
> the two
> > > technologies made Eventlet much more appealing to work with.  Thus my
> > > suggestion that we'll get more contributions if we go with Eventlet.
>  That
> > > said, if there's some technical reason that one system is better for
> our
> > > needs than the other, of course that trumps evangelism.
> > > HTH,
> > > Michael
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> > >
> >
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