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Install Python the right way

Installing Python for me has always been a pain. There are way too many “suggested” way to install it, too many strategies to handle different versions and projects’ dependencies… virtualenv, pip, pip3, pyenv, pipenv, brew. It’s a mess. And if you want your favorite IDE to automatically play along with your installations, well, things get more and more confused.

Until today!

I spent a night and a morning fooling around with python versions and virtual environments, until I arrived to the perfect working solution. It’s actually a cocktail of well balanced and tasty ingredients:

  • pyenv: to efficiently install and handle different versions of Python
  • pipenv: to isolate projects’ dependencies
  • PyCharm: the definitive IDE for python developers, it will fit perfectly this setup
  • some smart tweaks to your ~/.profile

pyenv

First thing first: install your next favorite toy

$ brew install pyenv

Then add pyenv init to your shell to enable shims and autocompletion

$ echo -e 'if command -v pyenv 1>/dev/null 2>&1; then\n  eval "$(pyenv init -)"\nfi' >> ~/.profile

That’s it. You can now install different Pythons compiling them directly from source

$ pyenv install 2.7.8
$ pyenv install 3.6.8
$ pyenv versions
  system
  2.7.8
* 3.6.8 (set by /Users/davide/.pyenv/version)

Now you’ll be able to setup a global version or a specific version to be used in specific folders

$ pyenv global 3.6.8
$ pyenv local 2.7.6
# the last cmd creates a .python-version file in the current directory.
# The local version overrides the global one.

At this link you can find a comprehensive pyenv command reference.

pipenv

The official guides instructs to install pipenv through HomeBrew:

$ brew install pipenv

What worked for me was instead the old fashioned:

$ sudo -H pip install -U pipenv

I won’t list pipenv commands and description, you can find them here.

PyCharm

PyCharm will automatically try to install the dependencies listed in the Pipfile; but almost surely it will fail.

Here below some tweaks to make the magic happen:

First of all add the following to your ~/.profile

# Run the following command to find the user base's binary directory:
$ python -m site --user-base

# A sample output can be
/Users/davide/.local

# Add bin to this path to receive a string for adding to the ~/.profile file, for example:
$ export PATH="$PATH:Users/jetbrains/.local/bin"
$ source ~/.profile

Now you can get back to PyCharm:

  • look for Project Interpreter in the Preferences Panel.
  • click on the small gear icon on the right / click on ADD

Now here there is a small gotcha that made me crazy spending a ton of time, so pay attention:

  • I know you want to setup a Pipenv Environment, but STFU, trust me and click on Virtualenv Environment on the left menu.
  • Check Existing Enviroment and select the correct pyenv’s python installation / click ok
  • Now click again on the small gear icon, and this time click on Pipenv Environment on the left menu
  • The base interpreter will be available; select it! (at current time, if you don’t follow what I wrote here above you won’t find it)

PyCharm will create the environment using the global (or local) python version set with pyenv.

Happy coding!