Pipenv & Virtual Environments

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This tutorial walks you through installing and using Python packages.

It will show you how to install and use the necessary tools and make strong recommendations on best practices. Keep in mind that Python is used for a great many different purposes, and precisely how you want to manage your dependencies may change based on how you decide to publish your software. The guidance presented here is most directly applicable to the development and deployment of network services (including web applications), but is also very well suited to managing development and testing environments for any kind of project.

Note

This guide is written for Python 3, however, these instructions should work fine on Python 2.7—if you are still using it, for some reason.

☤ Make sure you’ve got Python & pip

Before you go any further, make sure you have Python and that it’s available from your command line. You can check this by simply running:

$ python --version

You should get some output like 3.6.2. If you do not have Python, please install the latest 3.x version from python.org or refer to the Installing Python section of The Hitchhiker’s Guide to Python.

Note

If you’re newcomer and you get an error like this:

>>> python
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
NameError: name 'python' is not defined

It’s because this command is intended to be run in a shell (also called a terminal or console). See the Python for Beginners getting started tutorial for an introduction to using your operating system’s shell and interacting with Python.

Additionally, you’ll need to make sure you have pip available. You can check this by running:

$ pip --version
pip 9.0.1

If you installed Python from source, with an installer from python.org, or via Homebrew you should already have pip. If you’re on Linux and installed using your OS package manager, you may have to install pip separately.

☤ Installing Pipenv

Pipenv is a dependency manager for Python projects. If you’re familiar with Node.js’ npm or Ruby’s bundler, it is similar in spirit to those tools. While pip can install Python packages, Pipenv is recommended as it’s a higher-level tool that simplifies dependency management for common use cases.

Use pip to install Pipenv:

$ pip install --user pipenv

Note

This does a user installation to prevent breaking any system-wide packages. If pipenv isn’t available in your shell after installation, you’ll need to add the user base’s binary directory to your PATH.

On Linux and macOS you can find the user base binary directory by running python -m site --user-base and adding bin to the end. For example, this will typically print ~/.local (with ~ expanded to the absolute path to your home directory) so you’ll need to add ~/.local/bin to your PATH. You can set your PATH permanently by modifying ~/.profile.

On Windows you can find the user base binary directory by running py -m site --user-site and replacing site-packages with Scripts. For example, this could return C:\Users\Username\AppData\Roaming\Python36\site-packages so you would need to set your PATH to include C:\Users\Username\AppData\Roaming\Python36\Scripts. You can set your user PATH permanently in the Control Panel. You may need to log out for the PATH changes to take effect.

☤ Installing packages for your project

Pipenv manages dependencies on a per-project basis. To install packages, change into your project’s directory (or just an empty directory for this tutorial) and run:

$ cd myproject
$ pipenv install requests

Pipenv will install the excellent Requests library and create a Pipfile for you in your project’s directory. The Pipfile is used to track which dependencies your project needs in case you need to re-install them, such as when you share your project with others. You should get output similar to this (although the exact paths shown will vary):

Creating a Pipfile for this project...
Creating a virtualenv for this project...
Using base prefix '/usr/local/Cellar/python3/3.6.2/Frameworks/Python.framework/Versions/3.6'
New python executable in ~/.local/share/virtualenvs/tmp-agwWamBd/bin/python3.6
Also creating executable in ~/.local/share/virtualenvs/tmp-agwWamBd/bin/python
Installing setuptools, pip, wheel...done.

Virtualenv location: ~/.local/share/virtualenvs/tmp-agwWamBd
Installing requests...
Collecting requests
  Using cached requests-2.18.4-py2.py3-none-any.whl
Collecting idna<2.7,>=2.5 (from requests)
  Using cached idna-2.6-py2.py3-none-any.whl
Collecting urllib3<1.23,>=1.21.1 (from requests)
  Using cached urllib3-1.22-py2.py3-none-any.whl
Collecting chardet<3.1.0,>=3.0.2 (from requests)
  Using cached chardet-3.0.4-py2.py3-none-any.whl
Collecting certifi>=2017.4.17 (from requests)
  Using cached certifi-2017.7.27.1-py2.py3-none-any.whl
Installing collected packages: idna, urllib3, chardet, certifi, requests
Successfully installed certifi-2017.7.27.1 chardet-3.0.4 idna-2.6 requests-2.18.4 urllib3-1.22

Adding requests to Pipfile's [packages]...
P.S. You have excellent taste! ✨ 🍰 ✨

☤ Using installed packages

Now that Requests is installed you can create a simple main.py file to use it:

import requests

response = requests.get('https://httpbin.org/ip')

print('Your IP is {0}'.format(response.json()['origin']))

Then you can run this script using pipenv run:

$ pipenv run python main.py

You should get output similar to this:

Your IP is 8.8.8.8

Using $ pipenv run ensures that your installed packages are available to your script. It’s also possible to spawn a new shell that ensures all commands have access to your installed packages with $ pipenv shell.

☤ Next steps

Congratulations, you now know how to install and use Python packages! ✨ 🍰 ✨

☤ Fancy Installation of Pipenv

To install pipenv in a fancy way, we recommend using pipsi.

Pipsi is a powerful tool which allows you to install Python scripts into isolated virtual environments.

To install pipsi, first run this:

$ curl https://raw.githubusercontent.com/mitsuhiko/pipsi/master/get-pipsi.py | python

Follow the instructions, you’ll have to update your PATH.

Then, simply run:

$ pipsi install pew
$ pipsi install pipenv

To upgrade pipenv at any time:

$ pipsi upgrade pipenv

This will install both pipenv and pew (one of our dependencies) in an isolated virtualenv, so it doesn’t interfere with the rest of your Python installation!

☤ Referentially Transparent Installation of Pipenv

Nix provides atomic upgrades and rollbacks, it’s reliable and reproducible thanks to keeping all dependencies isolated all the way down to libc.

Once installed simply run:

$ nix-env --install --attr pipenv

☤ Pragmatic Installation of Pipenv

If you have a working installation of pip, and maintain certain “toolchain” type Python modules as global utilities in your user environment, pip user installs allow for installation into your home directory. Note that due to interaction between dependencies, you should limit tools installed in this way to basic building blocks for a Python workflow like virtualenv, pipenv, tox, and similar software.

To install:

$ pip install --user pipenv

For more information see the user installs documentation, but to add the installed cli tools from a pip user install to your path, add the output of:

$ python -c "import site; import os; print(os.path.join(site.USER_BASE, 'bin'))"

To upgrade pipenv at any time:

$ pip install --user --upgrade pipenv

☤ Crude Installation of Pipenv

If you don’t even have pip installed, you can use this crude installation method, which will bootstrap your whole system:

$ curl https://raw.githubusercontent.com/kennethreitz/pipenv/master/get-pipenv.py | python

Congratulations, you now have pip and Pipenv installed!