chore(ci/cd): add pipelines + modernize repo

[joshua-goldstein]

This PR adds a CD pipeline for pydgraph. We also bring the repo into the modern era to support Python 3.11, and use modern build tools. Some noteworthy points:

• python setup.py [command] is being deprecated (see here e.g.).
• The correct approach now is to use "front end" build tools like python -m build and pip install -e . instead of invoking setup.py directly
• We introduce a pyproject.toml file, which deprecates setup.py, requirements.txt, setup.cfg, etc.
• We remove requirements.txt since this information can be found in pyproject.toml
• Dev requirements introduced as optional dependencies in pyproject.toml (use pip install .[dev] from local repo, or pip install pydgraph[dev] once it is pushed to pypi)
• Test framework is unified (i.e. local tests and CI tests use the same script local-test.sh)
• README and PUBLISHING updated to reflect the above changes

[mangalaman93]

I like this method of setting up the cluster more reliable. Maybe we should consider doing this for dgo too.

[mangalaman93]

I don't we need to follow calver for pydgraph. We should just do a minor release instead

[joshua-goldstein]

I agree it is not clean but unfortunately there are already calver releases for pydgraph: https://github.com/dgraph-io/pydgraph/releases

The latest release is v21.03.0. The table here was not updated.

[mangalaman93]

limit the line width

[joshua-goldstein]

done

[mangalaman93]

why not requirements.txt?

[joshua-goldstein]

There are two "use-cases" so to speak:

• If I am a developer of an application that only needs to import pydgraph, when I run pip install pydgraph it will pull the needed dependencies (grpcio, protobuf). Also, these dependencies are now captured by the pyproject.toml file. There should be only one source of truth and we should not keep the same information in two places (unless necessary).
• If I am working on developing pydgraph, then I will need certain build / testing tooling, so I created this requirements_dev file for exactly those dependencies.

[mangalaman93]

Thanks for cleaning up the repo. Should we mention somewhere that we don't support python 2 anymore?

[joshua-goldstein]

Thanks for cleaning up the repo. Should we mention somewhere that we don't support python 2 anymore?

No problem. This is mentioned in the pyproject.toml file already, I think that should be sufficient.

[matthewmcneely]

@joshua-goldstein Timely! I was struggling getting the testing (tox) working this week. Is there a plan to move to a more simple setup (basic unittest for instance)?

[joshua-goldstein]

@joshua-goldstein Timely! I was struggling getting the testing (tox) working this week. Is there a plan to move to a more simple setup (basic unittest for instance)?

Yes, finally things are in working order now... With this PR tests should work locally. I just migrated to use pytest for now. We still need a script to do the cluster setup and tear down, so bash scripts/local-test.sh will do the cluster setup and then run the test suite. I think most of the tests we have here are integration tests.