When using pyenv and it’s pyenv-virtualenv -plugin, the activated virtualenv does not include the /bin -directory of the base python version in the PATH.

Background

pyenv

pyenv lets you easily switch between multiple versions of Python. It’s simple, unobtrusive, and follows the UNIX tradition of single-purpose tools that do one thing well.

pyenv-virtualenv

pyenv-virtualenv is a pyenv plugin that provides features to manage virtualenvs and conda environments for Python on UNIX-like systems.

Python environment at the time

  1. pyenv installed as defined in the Basic github checkout
  2. pyenv-virtualenv installed as defined here

  3. python version 3.6.4 installed

     $ pyenv install 3.6.4
 $ pyenv versions
     system
     3.6.4

  4. virtualenv for Ansible created

     $ pyenv virtualenv 3.6.4 ansible
 $ pyenv virtualenvs
     3.6.4/envs/ansible (created from /home/askolsam/.pyenv/versions/3.6.4)
     ansible (created from /home/askolsam/.pyenv/versions/3.6.4)

  5. Ansible 2.5.6 installed

     $ pyenv activate ansible
 $ pip install ansible==2.5.6

Problem

I was trying to update an local ansible module from python 2 to 3, but command 2to3 just returned ‘command not found’:

    $ pyenv activate ansible
    $ python --version
    Python 3.6.4
    $ pyenv which 2to3
    pyenv: 2to3: command not found
    The '2to3' command exists in these Python versions:
      3.6.4
    $ pyenv deactivate

    $ pyenv global 3.6.4
    $ python --version
    Python 3.6.4
    $ pyenv which 2to3
    /home/askolsam/.pyenv/versions/3.6.4/bin/2to3

Solution

Someone else had this same issue too. The solution is not to use pyenv activate but pyenv global or pyenv local:

    $ pyenv global ansible 3.6.4
    $ pyenv version
    ansible (set by /home/askolsam/.pyenv/version)
    3.6.4 (set by /home/askolsam/.pyenv/version)

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