Ian Wienand 67f223b53a Partial revert "Ensure wheel exists for build-release-python"; move to ensure-pip
This partially reverts commit
3f961ce202d7d24e2944de09636b35cec9c13bf6.

This alternative installs wheel with the ensure-pip role instead of in
a separate role.  wheel is very closely linked with pip install
operations so this isn't a large overreach of the role.

I suggest this for several reasons; firstly the python-wheel role
doesn't try to install packages, so we end up with mixed system pip
and upstream versions of wheel most of the time.  This is the type of
thing that has proven problematic in the past.  It also installs via
pip --user; something we've already had problems with tox when for
various reasons roles want to run this as non-zuul user.  Using
ensure-pip we keep the packaged versions together.

[1] did try to install wheel with root, but during runtime which
didn't work due to sudo being revoked.  This should work for the
existing build-python-release job, because it already includes
ensure-pip in pre-run via playbooks/python/pre.yaml

I believe our conclusion on the ensure-* roles was that requiring
root/become: for installation is OK, but we should have a no-op path
if the tools are found.  This is consistent with that approach
(i.e. if you want wheel and can't do sudo, you should pre-install it
on your image using whatever you build that with).

This adds a check to the existing "is pip installed" check to also
check if wheel packages are available.  If not we trigger the install
path.

This revealed some issues with RedHat.yaml -- we can always install
Python 3 (packages available for CentOS 7) so remove that check, and
if Ansible is running under Python 2; ensure we install the
dependencies too (not only if it is forced).

Update the documentation to describe that it will enable support for
bdist_wheel, and add a basic sanity test that wheels are produced by
pip.  The existing build-python-release job is kept; although it is
modified to use the playbooks/python/pre.yaml playbook as the build
job does.

Change-Id: I2ab11bb45b6b2a49d54db39195228ab40141185c
[1] https://review.opendev.org/#/c/736001/5/roles/build-python-release/tasks/main.yaml
2020-06-18 12:51:56 +00:00
..

Ensure pip is available

This role is intended install the requirements for the pip module on hosts.

Jobs that also wish to call pip via shell commands directly can also use this to ensure pip is available. However, it should be noted that calling pip is ambiguous when supporting many platforms. On some platforms it may install the package under the Python 2 interpreter and in others Python 3. You should use a qualified name (pip2 or pip3) to avoid confusion.

This role will also wheel components sufficient to run bdist_wheel builds or pip wheel on a source tree.

Role Variables

Output Variables

This variable will be set to a command appropriate for general usage with the pip module virtualenv_command argument on the host. On Python 3 hosts this will be the inbuilt venv module, on Python 2 hosts the virtualenv package will be installed (this is avoided on Python 3 hosts as an unnecessary dependency).