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 Your name     Boris Bobrov  Your email address     breton@cynicmansion.ru  T..."

2014-03-20T21:26:31Z

Created page with "This application was submitted to Melange with compliance to GNU template. Pasting it here. <pre> Your name Boris Bobrov Your email address breton@cynicmansion.ru T..."

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This application was submitted to Melange with compliance to GNU template. Pasting it here.

<pre>
Your name
Boris Bobrov

Your email address
breton@cynicmansion.ru

The name of the project
Mediagoblin: Python 3 port + switch to Alembic

Summary
Port all of MediaGoblin's code to python 3: https://issues.mediagoblin.org/ticket/813
Currently MediaGoblin uses sqlalchemy-migrate, but it's fairly outdated and unmaintained.
Port the migration infrastructure to using Alembic instead. Which is also python3-compatible.

Benefits
Python 3 is a new modern language that gaines popularity.
Also sqlalchemy-migrate used there is old and should be changed to a new shiny Alembic

Deliverables
All code will be python3.3-compatible, it means, that there the whole codebase will work with python 2.6, 2.7, 3.3+, maybe 3.2.
Minimal requirements' versions will be determined and the code will be ported to use them.
Alembic will be switched to sqlalchemy-migrate. Alembic is a database-schema migration tool.

Plan
A rough plan:
1. do something about Paste. Paste as well as pastescript is python3-incompatible.
- Drop it!
2. sort out versions of dependencies. Babel < 1.0 does not support py3. Maybe switch to newer versions of babel? Etc.
3. adopt tox -- https://bitbucket.org/hpk42/tox, use it for different Python versions and interpreters.
4. follow suggestion on #813: "Start porting MediaGoblin's code to python 3 generally. Ignore migrations, just support MediaGoblin "starting with the latest database schema", or even easier, set up your database on the python 2 branch before you git checkout the python 3 branch. ;)"
- There is an option to use "six". I suggest not to use it, for code cleanness. If some compatibility code will be required, it will be shipped in _compat module.
- http://python3porting.com/noconv.html suggests to convert to python3 and then convert back to python2. I agree with that and will do so.
- Hold up to ideas listed on http://lucumr.pocoo.org/2013/5/21/porting-to-python-3-redux/, like "Test for 2.x not 3.x".
- The conversion will look like this: 3.3 -> 2.7 -> 2.6 [-> 3.2] [-> 3.4?].
- To minimize the number of errors need to be fixed during an iteration, the conversion will be done by a number of fixes. A fix is a line from "2to3 -l". Every "fix" will be tested in order mentioned above, after it gives 0 errors, another one will be applied.
5. Write migrations
- Switch to Alembic
- It still doesn't support hacks around SQLite migrations.
- But there is a workaround which looks small and which we could use perhaps -- https://github.com/klugjohannes/alembic-sqlite
6. if time left, backport to 3.2
A little script involving 2to3 shows that these types of changes are required:
import, set_literal, input, idioms, print, dict, ws_comma (sorted asc).
Timeline:
Bonding period: getting to know architecture better, reading requirements' changelogs, experimenting.
19 May -- 27 May: drop Paste, drop sqlalchemy-migrate, getting dependencies, fix tests
28 May -- 1 June: adopting tox, making current tests pass and getting failures on python 3.
2 June -- 15 June: porting
15 June -- 27 June (mid-term): if everything is done, porting to python 3.2. Else finishing what remains. Or start switching to Alembic.
30 June -- 20 Jule: integrating Alembic
31 Jule -- 11 August: backporting old migrations to Alembic

Communication
We are going to chat in email, mailing lists and IRC. My nick in IRC is breton, I already hang out in #mediagoblin on freenode.
I use git, mediagoblin is stored in git, we shall work using it.

Qualification
Experience:
3.5 years of Python
3 years of Django
3.5 years of C in university
1.5 years of C++ in university
4 years of javascript (though I don't write too much in it); with jQuery and pure
6 years of HTML and CSS
1.5 year of Scheme and 12 months of Common Lisp
basic knowledge of system administration (set up nginx, uwsgi etc, familiar with cron, shell scripting)
a couple of FreeBSD kernel modules
I use
Debian as main OS
git (mercurial where required)
vim
I liked the project because it's:
1. MediaGoblin. I like it's idea and what people do there;
2. Python;
3. Python 3. I don't have too much experience in Python 3, and I want to a) learn it better and b) learn how to port to it.
You can find my github repo here: https://github.com/bretonium/
I don't know some of the tools used there, such as Paste. I don't think it's a problem, because one of the subtasks is to drop it.
</pre>

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Breton: Created page with "This application was submitted to Melange with compliance to GNU template. Pasting it here.
Your name Boris Bobrov Your email address breton@cynicmansion.ru T..."