Hi all,
> The sdist step creates a package that should be installed into each
> tox environment. If the tox environment has cython when this apache
> beam package is installed, it should be used. Nose (or whatever)
> should then run the tests.
>
I spent some time this weekend trying to understand the Beam python build
process, and here’s an overview of what I’ve learned:
- the :sdks:python:sdist gradle task creates the source tarball (no
surprises there)
- the protobuf stubs are generated during this process
- the sdist is provided to tox, which installs it into the the
virtualenv for that task
- for *-cython tasks, tox installs the cython dep and, as Ahmet
asserted, python setup.py nosetests performs the cythonization.
- this cythonized build overrides the one installed by tox
Here’s what I learned about the current status of tests wrt cython:
- cython tox tasks *are* using cython (good!)
- non-cython tox tasks *are not* using cython (good!)
- none of the GCP or integration tests are using cython (bad?)
- This is because the build is only cythonized when python setup.py
nosetests is used in conjunction with tox (tox installs cython, python
setup.py nosetests compiles it).
- GCP tests don't install cython. ITs don't use tox.
To confirm my understanding of this, I created a PR [1] to assert that a
cythonized or pure-python build is being used. A cythonized build is
expected by default on linux systems unless a special flag is provided to
inform the test otherwise. It appears as though the portable tests passed
(i.e. used cython), but I forgot to add the assertion for those; like the
other ITs they are not using cython.
*Questions:*
- Is the lack of cython for ITs expected and/or desired?
- Why aren't ITs using tox? It's quite possible to pass arguments into
tox to control it's behavior. For example, it seems reasonable that
run_integration_test.sh could be inside tox
*Next Steps:*There has been some movement in the python community to solve
problems around build dependencies [2] and toolchains [3]. I hope to have
a proposal for how to simplify this process soon.
[1] https://github.com/apache/beam/pull/10058
[2] https://www.python.org/dev/peps/pep-0517/
[3] https://www.python.org/dev/peps/pep-0518/
-chad
