ARROW-5805: [Python] Dockerize (add to docker-compose) Python Travis CI job

[rok]

This is to resolve ARROW-5805.

[wesm]

@fsaintjacques can you coordinate this patch with the one you just put up for the C++ build?

[wesm]

Why did you remove this?

[xhochy]

pytest=5.0 includes this now

[wesm]

ah, thanks

[fsaintjacques]

@wesm the cpp-ci image found in ARROW-5803 does not use conda, do you want me to convert this python image to avoid conda or tackle ARROW-5804 which is cpp with conda.

On this subject, I think we should have most tests conda-less with system/bundled dependencies, and have a single CI entry test with conda (both C++ and python). This will be more reflective on how new developers and package maintainers experience the build.

[wesm]

@fsaintjacques Yes I think that we should have a combined C++/Python docker-compose entry that uses dependencies from conda

[fsaintjacques]

My suggestion also imply de-confa-ying the other images (since the base arrow:cpp is relying on conda), is the community fine with this (@xhochy, @kszucs)?

Note that this patch was initially implemented replacing cpp by removing conda, I ended up using cpp-ci instead to minimize the breaking changes.

[xhochy]

My suggestion also imply de-confa-ying the other images (since the base arrow:cpp is relying on conda), is the community fine with this (@xhochy, @kszucs)?

Note that this patch was initially implemented replacing cpp by removing conda, I ended up using cpp-ci instead to minimize the breaking changes.

Actually we should try to keep conda in most images as this is the ecosystem we can control best and it is our recommendation for the setup for Python users, our currently most popular user base.

[wesm]

How would you all like to proceed with this patch?

[kszucs]

@wesm I'm doing a pretty heavy undertaking against the docker-compose.yml
I can put up a PR tomorrow, it'd nice if you could wait for it.

[wesm]

No problem. I was just scanning through the patch queue

[rok]

@kszucs I'd be happy to continue working on this, but I'm not clear on the direction: are we keeping conda here or not? Should we have a python image with conda and one without?

[wesm]

Closing as this is superseded by the GitHub Actions patch