Re: [RFC PATCH v3 00/20] configure: create a python venv and ensure meson, sphinx

[Daniel P . Berrangé]

On Tue, Apr 25, 2023 at 01:22:38PM -0400, John Snow wrote:
> On Tue, Apr 25, 2023, 1:17 PM Daniel P. Berrangé <berrange@redhat.com>
> wrote:
> 
> > On Mon, Apr 24, 2023 at 04:02:28PM -0400, John Snow wrote:
> > > GitLab CI: https://gitlab.com/jsnow/qemu/-/pipelines/846869409
> > >            (All green, except Python self-tests, see below)
> > >
> > > This patch series creates a mandatory python virtual environment
> > > ("venv") during configure time and uses it to ensure the availability of
> > > meson and sphinx.
> > >
> > > See https://www.qemu.org/2023/03/24/python/ for details. The summary is
> > > that the goal of this series is to ensure that the `python` used to run
> > > meson is the same `python` used to run Sphinx, tests, and any build-time
> > > python scripting we have. As it stands, meson and sphinx (and their
> > > extensions) *may* run in a different python environment than the one
> > > configured and chosen by the user at configure/build time.
> > >
> > > The effective change of this series is that QEMU will now
> > > unconditionally create a venv at configure-time and will ensure that
> > > meson (and sphinx, if docs are enabled) are available through that venv.
> > >
> > > Some important points as a pre-emptive "FAQ":
> > >
> > > - This venv is unconditionally created and lives at {build_dir}/pyvenv.
> > >
> > > - The python interpreter used by this venv is always the one identified
> > >   by configure. (Which in turn is always the one specified by --python
> > >   or $PYTHON)
> > >
> > > - *almost* all python scripts in qemu.git executed as part of the build
> > >   system, meson, sphinx, avocado tests, vm tests or CI are always
> > >   executed within this venv.
> > >
> > >   (iotests are not yet integrated; I plan to tackle this separately as a
> > >   follow-up in order to have a more tightly focused scope on that
> > >   series.)
> > >
> > > - It remains possible to build and test fully offline.
> > >   (In most cases, you just need meson and sphinx from your distro's
> > repo.)
> > >
> > > - Distribution packaged 'meson' and 'sphinx' are still utilized whenever
> > >   possible as the highest preference.
> > >
> > > - Vendored versions of e.g. 'meson' are always preferred to PyPI
> > >   versions for speed, repeatability and ensuring tarball builds work
> > >   as-is offline.
> > >
> > >   (Sphinx will not be vendored, just like it already isn't.)
> > >
> > > - Missing dependencies, when possible, are fetched and installed
> > >   on-demand automatically to make developer environments "just work".
> > >
> > > - Works for Python 3.7 and up, on Fedora, OpenSuSE, Red Hat, CentOS,
> > >   Alpine, Debian, Ubuntu, NetBSD, OpenBSD, and hopefully everywhere
> > >
> > > - No new dependencies (...for most platforms. Debian and NetBSD get an
> > >   asterisk.)
> > >
> > > - The meson git submodule is unused after this series and can be removed.
> > >
> > > For reviewers, here's how the series is broken up:
> > >
> > > Patch 1 is a testing pre-req. Note that even with this patch,
> > > 'check-python-minreqs' and 'check-python-tox' CI jobs will both still
> > > fail on origin/master because this series requires 3.7+, but
> > > origin/master is currently still 3.6+.
> > >
> > > - python: update pylint configuration
> > >
> > > Patches 2-8 add the mkvenv script. The first patch checks in the barest
> > > essentials, and each subsequent patch adds a workaround or feature one
> > > at a time.
> > >
> > > - python: add mkvenv.py
> > > - mkvenv: add console script entry point generation
> > > - mkvenv: Add better error message for missing pyexapt module
> > > - mkvenv: generate console entry shims from inside the venv
> > > - mkvenv: work around broken pip installations on Debian 10
> > > - mkvenv: add nested venv workaround
> > > - mkvenv: add ensure subcommand
> > >
> > > Patches 9-11 modify our testing configuration to add new dependencies as
> > > needed.
> > >
> > > - tests/docker: add python3-venv dependency
> > > - tests/vm: Configure netbsd to use Python 3.10
> > > - tests/vm: add py310-expat to NetBSD
> > >
> > > Patch 12 changes how we package release tarballs.
> > >
> > > - scripts/make-release: download meson==0.61.5 .whl
> > >
> > > Patches 13-16 wire mkvenv into configure and tests.
> > >
> > > - configure: create a python venv unconditionally
> > > - configure: use 'mkvenv ensure meson' to bootstrap meson
> > > - configure: add --enable-pypi and --disable-pypi
> > > - tests: Use configure-provided pyvenv for tests
> > >
> > > Patches 17-20 delegate Sphinx bootstrapping to mkvenv. Some of these
> > > changes could be folded earlier in the series (like the diagnose()
> > > patch), but I'm keeping it separate for review for now.
> > >
> > > - configure: move --enable-docs and --disable-docs back to configure
> > > - mkvenv: add diagnose() method for ensure() failures
> > > - configure: use --diagnose option with meson ensure
> > > - configure: bootstrap sphinx with mkvenv
> >
> > I'm not sure this last bit is working.
> >
> > I uninstalled meson and python3-sphinx from my F38 host and ran
> > configure --target-list=x86_64-softmmu and got this:
> >
> > $ ./configure --target-list=x86_64-softmmu
> > Using './build' as the directory for build output
> > python determined to be '/usr/bin/python3'
> > python version: Python 3.11.3
> > MKVENV pyvenv
> > Configured python as
> > '/home/berrange/src/virt/qemu/build/pyvenv/bin/python3 -B'
> > MKVENV ensure meson>=0.61.5
> > WARNING: Skipping
> > /usr/lib/python3.11/site-packages/virt_firmware-1.5-py3.11.egg-info due to
> > invalid metadata entry 'name'
> > WARNING: Skipping
> > /usr/lib/python3.11/site-packages/virt_firmware-1.5-py3.11.egg-info due to
> > invalid metadata entry 'name'
> > WARNING: Location 'file:///home/berrange/src/virt/qemu/python/wheels' is
> > ignored: it is neither a file nor a directory.
> > ERROR: Could not find a version that satisfies the requirement
> > meson>=0.61.5 (from versions: none)
> > ERROR: No matching distribution found for meson>=0.61.5
> > WARNING: Skipping
> > /usr/lib/python3.11/site-packages/virt_firmware-1.5-py3.11.egg-info due to
> > invalid metadata entry 'name'
> > WARNING: Skipping
> > /usr/lib/python3.11/site-packages/virt_firmware-1.5-py3.11.egg-info due to
> > invalid metadata entry 'name'
> > WARNING: Skipping
> > /usr/lib/python3.11/site-packages/virt_firmware-1.5-py3.11.egg-info due to
> > invalid metadata entry 'name'
> > MKVENV ensure sphinx>=1.6.0
> > WARNING: Skipping
> > /usr/lib/python3.11/site-packages/virt_firmware-1.5-py3.11.egg-info due to
> > invalid metadata entry 'name'
> > WARNING: Skipping
> > /usr/lib/python3.11/site-packages/virt_firmware-1.5-py3.11.egg-info due to
> > invalid metadata entry 'name'
> > ERROR: Could not find a version that satisfies the requirement
> > sphinx>=1.6.0 (from versions: none)
> > ERROR: No matching distribution found for sphinx>=1.6.0
> >
> > *** Ouch! ***
> >
> > Could not ensure availability of 'sphinx>=1.6.0':
> >  • Python package 'sphinx' was not found nor installed.
> >  • No local package directory was searched.
> >  • mkvenv was configured to operate offline and did not check PyPI.
> >
> >
> > Sphinx not found/usable, disabling docs.
> > MKVENV ok!
> >
> >
> >
> > It says mkvenv was configured to run offline, but I didn't do
> > anything. I thought the intention was for developers it would
> > live download from PyPI ?
> >
> 
> Ah. So... with enable pypi being the default and with docs set to "auto", I
> actually fall back to not installing sphinx from pypi *by default*. It
> tries to locate it on your system and will enable docs if it can, but it
> doesn't try too hard and doesn't get upset if it fails.

Ah right, yes, I think that behaviour makes sense.

> Try passing --enable-docs to convince the build system you'd really
> definitely like docs, and it'll force the pypi access.

Ok will try.

With regards,
Daniel
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