Open Stack

On Friday, April 24, 2015 11:20:03 AM Joshua Harlow wrote:
> Sean Toner wrote:
> > If written to use python 3, I hope it will use all the new features
> > of python 3.4 moving forward.
> > 
> > For example, argument annotations, coroutines, asyncio, etc.  At my
> > last workplace, we tried to make our project python2 and 3
> > compatible (ie, you could run it under 2.7 or 3.3+) but this was
> > the worst of all worlds.
> 
> Likely the reality of things is different from the desires :)
> 
> I know we'd all love to just do the above (or some of us would like
> to), but we also need to think about what shiny new features really
> make the quality of nova any better (IMHO some of the above really
> don't change much for the better...)
> 
> Out of curiosity why was your experience 'the worst of all worlds'?

Like I answered to Victor, it means that you don't get the nice new 
features only available in python3 (argument annotations, coroutines, 
namespace packaging, etc) while at the same time dealing with the 
inconsistencies between python2 and 3 code.

For example, having to manage some imports, dealing with some functions 
now returning bytes instead of str, and all kinds of other fun :)

Here's one example of having to change an import:

try:
    from urllib.request import urlopen
    from urllib.parse import urlparse as urlparse
except ImportError:
    from urllib2 import urlopen
    from urlparse import urlparse

I also had some code that created a subprocess.Popen object to execute 
some command.  Some commands output got returned as a regular str, and 
some others got returned as bytes.  So I wound up in my class creating a 
defensive decorator function that called 

if  isinstance(output, bytes):
  return output.decode()

And that's just 2 that popped into my head :)  And it was frustrating 
having to do extra work, and yet not be able to partake of all the 
python3 goodies.

But, if this is a stepping stone to a pure python3 environment even if 
that takes until python2 to EOL, I'm ok with that :)

> 
> > Regards,
> > Sean
> > 
> > On Friday, April 24, 2015 04:34:48 AM Victor Stinner wrote:
> >> Hi,
> >> 
> >> Porting OpenStack applications during the Liberty Cycle was
> >> discussed
> >> last days in the thread "[oslo] eventlet 0.17.3 is now fully Python
> >> 3
> >> compatible".
> >> 
> >> I wrote a spec to port Nova to Python 3:
> >>     https://review.openstack.org/#/c/176868/
> >> 
> >> I mentioned the 2 other Python 3 specs for Neutron and Heat.
> >> 
> >> You can reply to this email, or comment the review, if you want to
> >> discuss Python 3 in Nova, or if you have any question related to
> >> Python 3.
> >> 
> >> See also the Python 3 wiki page:
> >>     https://wiki.openstack.org/wiki/Python3
> >> 
> >> Thanks,
> >> Victor
> >> 
> >> ___________________________________________________________________
> >> ___ ____ OpenStack Development Mailing List (not for usage
> >> questions) Unsubscribe:
> >> OpenStack-dev-request at lists.openstack.org?subject:unsubscribe
> >> http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev
> > 
> > ____________________________________________________________________
> > ______ OpenStack Development Mailing List (not for usage questions)
> > Unsubscribe:
> > OpenStack-dev-request at lists.openstack.org?subject:unsubscribe
> > http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev
> ______________________________________________________________________
> ____ OpenStack Development Mailing List (not for usage questions)
> Unsubscribe:
> OpenStack-dev-request at lists.openstack.org?subject:unsubscribe
> http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev