zuul-jobs

History

Ian Wienand 08bbd16c52 Add ensure-virtualenv This is part of the efforts to remove pip-and-virtualenv from our base images [1]. There are some users who specifically require the virtualenv command (perhaps, like dib, they have some code that uses the activate_this.py mechanisms it provides wich venv does not). This installs the virtualenv package for the currently running distribution. One of the main maintenance issues of pip-and-virtualenv is that tried to ensure that "virtualenv" created a Python 2 environment always by default. Now that we have Python 3 only distributions like current Fedora, this is not something we can continue to do (even if we wanted to, which we don't). What owns virtualenv and what it produces in our heterogeneous environment is messy, and I think the best we can do is document it as done here. [1] https://docs.opendev.org/opendev/infra-specs/latest/specs/cleanup-test-node-python.html Change-Id: I97d8bfb970ed2b5aaa02a0813899014c94994066	2020-04-28 06:09:54 +00:00
..
tasks	Add ensure-virtualenv	2020-04-28 06:09:54 +00:00
README.rst	Add ensure-virtualenv	2020-04-28 06:09:54 +00:00

Ian Wienand 08bbd16c52 Add ensure-virtualenv

This is part of the efforts to remove pip-and-virtualenv from our base
images [1].

There are some users who specifically require the virtualenv command
(perhaps, like dib, they have some code that uses the activate_this.py
mechanisms it provides wich venv does not).

This installs the virtualenv package for the currently running
distribution.

One of the main maintenance issues of pip-and-virtualenv is that tried
to ensure that "virtualenv" created a Python 2 environment always by
default.  Now that we have Python 3 only distributions like current
Fedora, this is not something we can continue to do (even if we wanted
to, which we don't).

What owns virtualenv and what it produces in our heterogeneous
environment is messy, and I think the best we can do is document it as
done here.

[1] https://docs.opendev.org/opendev/infra-specs/latest/specs/cleanup-test-node-python.html

Change-Id: I97d8bfb970ed2b5aaa02a0813899014c94994066

2020-04-28 06:09:54 +00:00

tasks

Add ensure-virtualenv

2020-04-28 06:09:54 +00:00

README.rst

Add ensure-virtualenv

2020-04-28 06:09:54 +00:00

README.rst

Ensure virtualenv is available

This role installs the requirements for the virtualenv command on the current distribution.

Users should be aware of some portability issues when using virtualenv:

Distributions differ on the interpreter that virtualenv is provided by, so by calling virtualenv with no other arguments means that on some platforms you will get a Python 2 environment and others a Python 3 environment.
If you wish to call virtualenv as a module (e.g. python -m virtualenv) you will need to know which interpreter owns the virtualenv package for your distribution; e.g. on some, such as Bionic, virtualenv is provided by python3-virtualenv but python refers to Python 2, so python -m virtualenv is not a portable way to call virtualenv.
virtualenv -p python3 is likely the most portable way to consistently get a Python 3 environment. virtualenv -p python2 may not work on some platforms without Python 2.
If you use Python 3 and do not require the specific features of virtualenv, it is likely easier to use Python's inbuilt python3 -m venv module to create an isolated environment. If you are using pip: in your Ansible roles and require an environment, see the documentation for :zuulensure-pip.