As described inline, deprecate the "source" install for CentOS 8.
Overwriting the packaged tools has long been a pain-point in our
images, and the best outcome is just not to play the game [1].
However, the landscape remains complicated. For example, RHEL/CentOS
8 introduces the separate "platform-python" binary, which seems like
the right tool to install platform tools like "glean" (simple-init)
with. However, platform-python doesn't have virtualenv (only the
inbuilt venv).
So that every element doesn't have to hard-code in workarounds for
these various layouts, create two new variables DIB_PYTHON_PIP and
DIB_PYTHON_VIRTUALENV to just "do the right thing". If you need is
"install a pip package" or "create a virtualenv" this should work on
all the platforms we support. If you know more specifically what you
want (e.g. must be a python3 virtualenv) then nothing stops elements
calling that directly (e.g. python3 -m virtualenv create); these are
just helper wrappers for base elements that need to be broadly
compatible.
[1] http://lists.openstack.org/pipermail/openstack-infra/2019-September/006483.html
Change-Id: Ia267a60eecfa8f4071dd477d86daebe07e9a7e38
This reverts commit ab89c7d69c.
This commit checked for DIB_PYTHON_VERSION and only installed the v3
packages. This is unfortunately backwards-incompatible, as consumers
such as the openstack gate are relying on this package installing pip
& virtualenv packages for python2 AND python3.
This was sort-of expressed in the docs, where it discusses what the
resulting setup of the system will be, but I've added a note to make
it clearer.
If we want to change this, I think we'll need either a new element, or
a non-defaulting flag.
Change-Id: I419dbdf4682394db68974944af1e5c432f3e0565
If DIB_PYTHON_VERSION is < 3 on the !redhat path, that means we're on
an older platform that may not have python3-virtualenv packages. Skip
install.
Ensure the order of operations happens by forcing the installs
Also add a note about limited platform support (patches welcome :)
Change-Id: I18412767f0ebf946d557a0a126285369e96af159
Recent changes in project-config have shown that we leave the system
in an inconsistent state when installing from source. On fedora, we
will have installed the python2 packages, but then used $DIB_PYTHON to
install python3 pip from source!
This tries to clarify the situation. As described in the document,
with package installs, we just install the $DIB_PYTHON packaged
versions.
Source installs want to take over the global namespace. This is the
price you pay for running the latest versions outside package managers
:) The only sane thing seems to be for us to normalise python2 &
python3 versions of pip, setuptools and virtualenv and then hacking
things such that "/usr/bin/pip" and "/usr/bin/virtalenv" remain
defaulted to python2 versions.
Documentation is added
Change-Id: Ibc6572b89e256d1f48b7fe7c672b8b9524dc704f
Currently we have all our elements and library files in a top-level
directory and install them into
<root>/share/diskimage-builder/[elements|lib] (where root is either /
or the root of a virtualenv).
The problem with this is that editable/development installs (pip -e)
do *not* install data_files. Thus we have no canonical location to
look for elements -- leading to the various odd things we do such as a
whole bunch of guessing at the top of disk-image-create and having a
special test-loader in tests/test_elements.py so we can run python
unit tests on those elements that have it.
data_files is really the wrong thing to use for what are essentially
assets of the program. data_files install works well for things like
config-files, init.d files or dropping documentation files.
By moving the elements under the diskimage_builder package, we always
know where they are relative to where we import from. In fact,
pkg_resources has an api for this which we wrap in the new
diskimage_builder/paths.py helper [1].
We use this helper to find the correct path in the couple of places we
need to find the base-elements dir, and for the paths to import the
library shell functions.
Elements such as svc-map and pkg-map include python unit-tests, which
we do not need tests/test_elements.py to special-case load any more.
They just get found automatically by the normal subunit loader.
I have a follow-on change (I69ca3d26fede0506a6353c077c69f735c8d84d28)
to move disk-image-create to a regular python entry-point.
Unfortunately, this has to move to work with setuptools. You'd think
a symlink under diskimage_builder/[elements|lib] would work, but it
doesn't.
[1] this API handles stuff like getting files out of .zip archive
modules, which we don't do. Essentially for us it's returning
__file__.
Change-Id: I5e3e3c97f385b1a4ff2031a161a55b231895df5b
