[Twisted-Python] Removing Python 2.6 Support after Twisted 15.1

Phil Mayers p.mayers at imperial.ac.uk
Thu Mar 19 06:05:50 MDT 2015


On 18/03/15 23:57, Glyph Lefkowitz wrote:

> Rather than just suggest we preserve the status quo and stay on 2.6
> forever to do indefinite free work to support Red Hat's obsolescence

You *definitely* shouldn't do that. Push back on RedHat, and tell 
customers to push back on RedHat. I say this to other projects.

As mentioned, if maintaining 2.6 support is anything other than a 
trivial amount of work, then it's totally reasonable to drop it.

> business, perhaps we should make a condition of dropping 2.6 support
> being a clear guide for getting a Twisted environment with py2.7 up
> and running on whatever appropriately decrepit environment is popular
> in the CentOS/RHEL user community?  I am annoyed with RH for lagging
> so much, but I don't want to make their customers' employees suffer
> for it.
>
> Phil - I do have a question though, since you seem to be a real life
> user with this use-case :).  If you want to use an old, unsupported
> version of Python, why do you want to deploy a new, updated version
> of Twisted on it?

Well, I don't want to use Python 2.6 per-se. It's what a large number of 
the systems we run have bundled, I have no need for newer 2.7 language 
features, and thus if I can *possibly* avoid it, I don't want to 
maintain the burden of deploying another version, even less so the 
burden of packaging it. We've done that in the past, it's non-trivial 
effort.

I've no specific need for a newer Twisted right now, but I can imagine 
things that might appear - support in listenSSL for ALPN for example, or 
HTTP/2 - that we could use if they appeared.

So, it's purely speculative. I have no current specific need.

> dstufft - is there a PyPy EPEL?  As long as we're telling people to
> change which Python to use, perhaps we should point them at an
> actually good one ;).

PyPy in EPEL 6 is currently sitting at 2.0.2. I've only tried it a few 
times and had mixed results; having to use psycopg2cffi was a bit of a 
pain, and I had some pathological performance issues, but it did 
basically work.

The RHEL SCLs OTOH... After Donald's pointer I took a look at them. They 
are... not great.

[Basically, they're built to think they run in one path, but installed 
in another, and you have to run it with a wrapper script that sets up 
LD_LIBRARY_PATH, PATH, PYTHONPATH, etc.

As opposed to what you'd think, a Python 2.7 compiled and installed 
into, say, /opt/python2.7, which you can just run directly.

Sigh...]

So my £0.02 is that recommending SCL for Python 2.7 on EL6 is something 
you would want to do with caution ;o)

I honestly wouldn't worry about it too much; RedHat's policies aren't 
and shouldn't be Twisted's problem. Do what's best for your development.

Cheers,
Phil




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