Drop python 2 support

[craigds]

Drops support for python 2. Fixes #34

This should probably go in the next minor release, i.e 0.5, rather than a 0.4.x.

We were possibly supporting 3.3 before as well, this drops that. The minimum supported python is now 3.4.

I'd like to drop 3.4 too, but some distros still use it, so maybe in a few months.

[rcoup]

This should probably go in the next minor release, i.e 0.4, rather than a 0.3.x.

👍

[rcoup]

Can you review the 2to3 casting of iterators to list/dict?

[craigds]

Just realised the released version is already 0.5x, so this would go into 0.6.0

[craigds]

I can repro the test failures only if I run them in a -alpine or -slim container (the tests use -alpine)

if I run them in a python:3.4 container they work fine. It also seems to work sometimes if I don't clear the pytest cache, but I'm not entirely sure about it.

[craigds]

okay. firstly, this isn't a new issue, but since I added python 3.4/3.5 tests in buildkite, it's happening here.

The error is that the request produced by the test doesn't have a content-type header for the CSV file in the multipart upload.

I suspect that's because the -slim and -alpine variants don't have file installed, and so can't guess the mimetype of the file.

$ docker run -it --rm -v $(pwd):/app -w /app python:3.4 file --mime-type text.csv
text.csv: inode/x-empty


$ docker run -it --rm -v $(pwd):/app -w /app python:3.4-slim file --mime-type text.csv
docker: Error response from daemon: OCI runtime create failed: container_linux.go:349: starting container process caused "exec: \"file\": executable file not found in $PATH": unknown.

Maybe the mimetypes python module also uses file under the hood? It has similar behaviour:

$ docker run -it --rm -v $(pwd):/app -w /app python:3.4 python -c 'import mimetypes ; print(mimetypes.guess_type("file:///app/text.csv"))'
('text/csv', None)


$ docker run -it --rm -v $(pwd):/app -w /app python:3.4-slim python -c 'import mimetypes ; print(mimetypes.guess_type("file:///app/text.csv"))'
(None, None)

I'll make the test agnostic to this, because it doesn't really matter.