Re: [Twisted-Python] A Proposal for reducing the burden of developing on Twisted by dropping Python 2 support (Craig Rodrigues)
Hi! Figured it might be helpful to just throw in the other viewpoint (that I'd hold). Which is -- I use a Python 2.7 [PyPy] not end of lifing in 2020 (or in the forseeable future -- and one by the way I'd wholeheartedly have recommended more of us use even before now :). At work, we develop even new applications on it, and likely will not have any plans to move anything really until at least a year or two, until PyPy3 matures and until we have time to do extensive benchmarking showing it isn't slower than PyPy2. So my personal opinion would be obviously "drop Py2 support immediately" -- nope kidding, just making sure you're still reading -- it's "keep it forever and we all suffer, hooray". I don't contribute to Twisted as much as I'd like (or should), and I fully recognize the huge efforts of others who hey shouldn't do free work just on my behalf -- but, in case it's valuable, FWIW dropping Py2 support would make me *less* likely to contribute :), since I couldn't rely on being able to use my own contributions -- perhaps though a decent solution to this side of things is for twisted to continue to pursue being more modular than it is today (i.e. break it up). -J On Wed, Mar 27, 2019 at 4:45 AM <twisted-python-request@twistedmatrix.com> wrote:
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1. Re: A Proposal for reducing the burden of developing on Twisted by dropping Python 2 support (Craig Rodrigues) 2. Drop support for Python 3.4? (Craig Rodrigues) 3. Re: Drop support for Python 3.4? (Glyph) 4. Re: A Proposal for reducing the burden of developing on Twisted by dropping Python 2 support (Adi Roiban)
---------- Forwarded message ---------- From: Craig Rodrigues <rodrigc@crodrigues.org> To: Twisted general discussion <twisted-python@twistedmatrix.com> Cc: Bcc: Date: Tue, 26 Mar 2019 19:35:58 -0700 Subject: Re: [Twisted-Python] A Proposal for reducing the burden of developing on Twisted by dropping Python 2 support
On Mon, Mar 25, 2019 at 3:15 AM Amber Brown <hawkowl@atleastfornow.net> wrote:
You can find the proposal here, in this handy-dandy Google Doc:
https://docs.google.com/document/d/1S4CGgZC09blLIdk3Zo7wBa75A9_JuuH_3akkyjN0...
Thanks for writing that doc. I think option 3 of making Twisted 19.4 the last Python 2 release, with security updates until 2021 is actually pretty reasonable.
-- Craig
---------- Forwarded message ---------- From: Craig Rodrigues <rodrigc@crodrigues.org> To: Twisted general discussion <twisted-python@twistedmatrix.com> Cc: Bcc: Date: Tue, 26 Mar 2019 19:59:01 -0700 Subject: [Twisted-Python] Drop support for Python 3.4? What do people think of dropping Twisted support for Python 3.4?
According to https://devguide.python.org/#status-of-python-branches
Python 3.4 EOL'd on March 19, 2019.
In the Python 3 world, we have Python 3.4, 3.5, 3.6, 3.7, and at the end of this year we will have Python 3.8.
That's quite a lot of Python versions to support.
Python 3.5 introduced async/await keywords, which are very relevant to Twisted: https://docs.python.org/3.5/whatsnew/3.5.html#whatsnew-pep-492
If it makes sense, it would be nice to use these keywords as first-level features in Twisted.
Since Amber brought up discussion of dropping Python 2.7 here: https://twistedmatrix.com/pipermail/twisted-python/2019-March/032234.html
I thought I would raise dropping Python 3.4 also. -- Craig
---------- Forwarded message ---------- From: Glyph <glyph@twistedmatrix.com> To: Twisted general discussion <twisted-python@twistedmatrix.com> Cc: Bcc: Date: Tue, 26 Mar 2019 22:04:17 -0700 Subject: Re: [Twisted-Python] Drop support for Python 3.4?
On Mar 26, 2019, at 7:59 PM, Craig Rodrigues <rodrigc@crodrigues.org> wrote:
What do people think of dropping Twisted support for Python 3.4?
According to https://devguide.python.org/#status-of-python-branches
Python 3.4 EOL'd on March 19, 2019.
In the Python 3 world, we have Python 3.4, 3.5, 3.6, 3.7, and at the end of this year we will have Python 3.8.
That's quite a lot of Python versions to support.
Python 3.5 introduced async/await keywords, which are very relevant to Twisted: https://docs.python.org/3.5/whatsnew/3.5.html#whatsnew-pep-492
If it makes sense, it would be nice to use these keywords as first-level features in Twisted.
Since Amber brought up discussion of dropping Python 2.7 here: https://twistedmatrix.com/pipermail/twisted-python/2019-March/032234.html
I thought I would raise dropping Python 3.4 also.
I'll let any 3.4 users speak for themselves if they're out there, but while I can imagine a host of reasons we might want to still support 2.7, I can't think of any that we'd want to hang on to 3.4 any longer than necessary. 3.5 still has the lingering benefit of a production(-ish) pypy, so we might not want to jump to 3.6-only anyway, but if it's unsupported by python core, let's get rid of it. Faster round trips through CI are reason enough :-).
-g
---------- Forwarded message ---------- From: Adi Roiban <adi@roiban.ro> To: Twisted general discussion <twisted-python@twistedmatrix.com> Cc: Bcc: Date: Wed, 27 Mar 2019 08:45:13 +0000 Subject: Re: [Twisted-Python] A Proposal for reducing the burden of developing on Twisted by dropping Python 2 support On Tue, 26 Mar 2019 at 04:52, Glyph <glyph@twistedmatrix.com> wrote:
On Mar 25, 2019, at 3:15 AM, Amber Brown <hawkowl@atleastfornow.net>
wrote:
Hi everyone,
Since the Python 2 EOL date is rapidly approaching, I thought it was
time we consider dropping Python 2 support.
I personally find that Python 2 compat adds a huge amount of overhead
when working on and maintaining Twisted, and think that with the current maintainer availability, dropping it sooner rather than later would have a beneficial effect on how much work we spend on shims/compat, complexity, and our ability to ship new features, as well as onboarding people who are interested in the project, but have no interest (or experience!) in Python 2.7.
Personally, I don't have this problem, but I'm certainly willing to
believe it's a bigger deal for others; especially others who perhaps have not even learned Python 2 at this point.
I am still using python 2.7 on all my projects, and I remember the sending patches supporting python 3 was an extra effort... I had to learn python 3 things, and then search for ways / workaround to implement something in a py2 + py3 way... read six documentation.
I guess that many Twisted developers don't have too much free time, this can add up.
For me learning py3 was ok as at some point I will use it...but I guess that for people who will never use py2 is just unwanted work.
Here's my question about this:
Who will do this work?
Personally, I'm not willing to commit to this. I know from experience
both on Twisted and other projects that maintaining multiple release branches, even one that's "maintenance only", requires at least one point-person for each branch at all times (usually a "release manager"). And backporting fixes inevitably gets harder and harder as the "maintenance" branch diverges from top-of-tree. If I have time to work on Twisted in my increasingly scarce spare time, I want it to be on something at least plausibly interesting, and manually backporting manual fixes to an unmaintained py2 branch that I don't even use doesn't qualify.
[SNIP]
Do we have py2-only users who are willing to take ownership of this
branch? Specific people willing to sign up for this responsibility for the next... how long? Three years? Five years?
I can help with backporting security fixed for the next 5 years, as I will use it.
I am still using 15.5 due to lack of python cryptography on all systems, and I have a fork for twisted.web with support for resources which can add custom `Expect: 100-continue` behaviour.
I am doing backporting and as long as there is a CI, is not that hard.
I hope there will be at least another person to help reviewing the backports.
So I'd rather be quite explicit that while we would not object to anyone filling these roles, someone still needs to step forward and fill them, and I'm not willing to commit the current team, such as it is, to work that I myself am unwilling to do. If nobody does step forward we should not claim to have security support for a dead / unmaintained branch.
Well.. this is free/libre software so I guess that nobody will be sued if we commit to something, and later we found out that this can't be done.
One of my rationales is that from some analysis of PyPI download statistics, the vast majority of Python 2 users are using old versions of Twisted, while nearly all our Python 3 users are on the latest version. As such, I believe freezing a version that will get security updates but no new features would not be a massive loss to those stuck on Python 2 for whatever reason.
I know that you detailed some of this on IRC, but: how old?
My sense would be that of course users stuck on py2 would have a more conservative upgrade cadence than py3 users, but that doesn't mean they never upgrade. How far behind are these py2 users, and does the curve suggest they're catching up or are most twisted downloads just like, version 1.3 on python 1.5.2 forever?
From my experience the upgrade is between 5 to 10 years. But the upgrade is done only because the system will be obsolete. Old version run in private networks, without Internet access with nobody willing to touch a working system.
PCI don't help. So far, they have only asked for TLS1.2 and removal of CBC Mode ciphers in SSH...and that is all. They have never complained about old OpenSSH or OpenSSL versions... and when you have custom old software, the PCI auditor have no clue.
I know more than 3 big companies which still have not upgraded to TLS 1.2 even with all the PCI audits...they always get extensions and workarounds.
Twisted's compatibility policy would still apply, ensuring that Python 2/3 compatible software using Twisted would be able to use the older Twisted version on Python 2, and the newer version on Python 3, as you would usually expect.
We have 2 big blockers here right now that would prevent doing this as things stand right now:
Twisted is not yet fully ported to Python 3, so there's no version where you can use all of Twisted on Python 3. This picture is way, way smaller than it has ever been, though - grab a module and start porting: http://blog.habnab.it/twisted-depgraph/ We still have Python 2 in production ourselves that requires Twisted; specifically:
Trac and several of our ancillary utilities around it. Happily this does seem to be fairly actively worked on: "opened 4 years ago, last modified 12 days ago" https://trac.edgewall.org/ticket/12130
Do we really need Trac? Maybe is time to move the tickets and wiki to GitHub.
Dogfood DNS: twisted.names doesn't work on python 3: https://twistedmatrix.com/trac/ticket/9496
I have never used Twisted.names in production. I tried to help with the review of twisted.names patches, and I remember there was not much interest for twisted.names So maybe we can get rid of it and move it to a separate project.
I don't think that we need to have everything in twisted core... if ldaptor is an external project, why we can't have twisted.names
Our front-end webserver might work on pypy3, but we have yet to move it over. Maybe that would be a good place to start?
If this proposal lights a fire under some folks to drive any of these projects to completion, that would be great!
My hope is that this proposal will light a fire and people using Twisted will more about Twisted.
I feel that Twisted stability and reduce number of defects is not helping the open source dev model. People will use Twisted, it just work and they forget about it. Or if it doesn't work, they can fix something on their project relatively easy...but takes a lot of effort to send upstream..so they will never put the effort required to have a fix upstream.
You can find the proposal here, in this handy-dandy Google Doc: https://docs.google.com/document/d/1S4CGgZC09blLIdk3Zo7wBa75A9_JuuH_3akkyjN0...
Comments are welcome, as well as which timeline seems reasonable.
Personally I feel like Option 1 is the most reasonable. We can't do option 3 because of the above blockers, and option 2 just seems random to me - why commit to 4 months of additional maintenance beyond when py2 itself is EOL? Maybe there's an option like, 1.5, where we de-support py2 at max(2020-01-01, "the date at which we no longer have any py2 code in production ourselves")?
If we keep the current prod infrastructure, I am not confident that we will no longer have py2 code in prod by the end of this year.
I don't feel that the current Twisted team have resource to maintain a custom infrastructure. I think that things will be better for everyone if for example of Twisted names we will just use the credit on Azure to keep the DNS and use more Software as a Service so that the team will spend more time on developing new feature than doing sysadmin work.
Dogfooding is a good thing, but in this case, I fell that it does not help.
-- Adi Roiban
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Julian Berman