diskimage-builder/diskimage_builder/elements/pip-and-virtualenv
Ian Wienand f0b70211c6 Use local mirror for ubuntu-minimal jobs
This adds "openstack-ci-mirrors" element which performs various
settings to get builds using local mirrors.  As a first step, we
convert ubuntu-minimal jobs

The main trick is that since infra mirrors are created with rerepo
they are not signed (they are recreated, not cloned, and not signing
is seen as a feature in that it deters external use).  So we need to
instruct debootstrap to ignore signing and also turn it off for
in-chroot apt.  Other than that, the existing DIB_DISTRIBUTION_MIRROR
works to redirect installs.

Remove "restricted" as it's not mirrored, and I don't think we want it
in here by default.

(I think DIB_DISTRIBUTION_MIRROR is a bit of an anti-pattern, because
it leaves the mirrors in the final image -- just because you use them
to build, doesn't mean you want them at runtime).  But we don't need
to fix that now, and we don't use any created images.)

This pauses fedora testing until the next change, which moves to using
local mirrors for testing on fedora/centos

Change-Id: I778bd05a1e615c27edf1c9f0a1409119a6b3a850
2017-06-21 12:01:31 +10:00
..
install.d/pip-and-virtualenv-source-install Trivial fix typos 2017-05-31 11:17:05 +07:00
test-elements Use local mirror for ubuntu-minimal jobs 2017-06-21 12:01:31 +10:00
element-deps Release 1.25.2 2017-02-02 11:20:00 +11:00
package-installs.yaml Release 1.25.2 2017-02-02 11:20:00 +11:00
pkg-map Adjust package mapping for SUSE family 2017-05-31 21:09:53 +02:00
README.rst Skip python3-virtualenv on <= trusty 2017-04-12 06:36:20 +10:00
source-repository-pip-and-virtualenv Move elements & lib relative to diskimage_builder package 2016-11-01 17:27:41 -07:00

==================
pip-and-virtualenv
==================

This element installs pip and virtualenv in the image.

Package install
===============

If the package installtype is used then these programs are installed
from distribution packages.  In this case, ``pip`` and ``virtualenv``
will be installed *only* for the python version identified by
``dib-python`` (i.e. the default python for the platform).

Distribution packages have worked out name-spacing such that only
python2 or python3 owns common scripts like ``/usr/bin/pip`` (on most
platforms, ``pip`` refers to python2 pip, and ``pip3`` refers to
python3 pip, although some may choose the reverse).

To install pip and virtualenv from package::

  export DIB_INSTALLTYPE_pip_and_virtualenv=package

Source install
==============

Source install is the default.  If the source installtype is used,
``pip`` and ``virtualenv`` are installed from the latest upstream
releases.

Source installs from these tools are not name-spaced.  It is
inconsistent across platforms if the first or last install gets to own
common scripts like ``/usr/bin/pip`` and ``virtualenv``.

To avoid inconsistency, we firstly install the packaged python 2
**and** 3 versions of ``pip`` and ``virtualenv``.  This prevents a
later install of these distribution packages conflicting with the
source install.  We then overwrite ``pip`` and ``virtualenv`` via
``get-pip.py`` and ``pip`` respectively.

The system will be left in the following state:

* ``/usr/bin/pip`` : python2 pip
* ``/usr/bin/pip2`` : python2 pip (same as prior)
* ``/usr/bin/pip3`` : python3 pip
* ``/usr/bin/virtualenv`` : python2 virtualenv

(note python3 ``virtualenv`` script is *not* installed, see below)

Source install is supported on limited platforms.  See the code, but
this includes Ubuntu and RedHat platforms.

Using the tools
===============

Due to the essentially unsolvable problem of "who owns the script", it
is recommended to *not* call ``pip`` or ``virtualenv`` directly.  You
can directly call them with the ``-m`` argument to the python
interpreter you wish to install with.

For example, to create a python3 environment do::

  # python3 -m virtualenv myenv
  # myenv/bin/pip install mytool

To install a python2 tool from pip::

  # python2 -m pip install mytool

In this way, you can always know which interpreter is being used (and
affected by) the call.

Ordering
========
Any element that uses these commands must be designated as
05-* or higher to ensure that they are first installed.