python 2 support

[xrmx]

I'm wondering if it's time to stop supporting superset on python 2. I created by mistake a virtualenv with python2 instead of python3 and sqllab does not work at all when non ascii encodable data is used. It breaks in the loggers, it breaks when poking with dataframes.
So given that airbnb is on python3 and tests does not catch any encoding issue is it time to stop supporting it?

[mistercrunch]

Python 2.7 is there to stay. In many environments people might now have the luxury to choose.

We use it in production at Airbnb. We could run 3.4 or 3.5 if we wanted but we'll probably make the switch when our standard images use distros that ship py3 by default.

So even though it reduce the surface for bugs, we're not dropping py2.7 support, I don't think there's a lot of projects that are doing that at the moment.

I'm not sure what your exact issues were, but most likely something that's easy to fix across the board with some environment (or perhaps database connection) setting.

[xrmx]

An easy reproducer for sqllab breaking with python2.7 is something like this on a table from the examples:

select 'ኴ' from anexampletable;

Closing then.

[rumbin]

Another fact that should be kept in mind:

python-ldap is not available for python3.
LDAP-auth is the sole reason why we run superset in a python2.7 venv.

[xrmx]

@rumbin except you can upgrade :) https://github.com/pyldap/pyldap.

[rumbin]

@xrmx thanks for pointing me to pyldap, it seems to work well!