The Easiest Way to Use a Python Virtual Environment with Git

In this story, I will explain why a virtual environment is necessary when developing in python. I will then explain how to set up and properly use a virtual environment with source control.

What is a Virtual Environment?

Setting up a virtual environment when building a python project is an essential step in the development process. A virtual environment allows dependencies to be separated between projects. A dependency is just some sort of module that is required for your project to run properly. As the dependency modules are updated, conflicts can arise between projects if dependencies are shared and the necessary versions are not the same. A virtual environment eliminates these conflicts by allowing the dependencies to be project specific and isolated from the system.

How to Do It

The process of setting up a virtual environment should be done for every project and is quite painless.

First, create a project directory and switch into it.

mkdir test-env && cd test-env

Venv is included with Python versions 3.3 and newer and is the default way of setting up virtual environments.

Next, run the script below within the directory to create the virtual environment:

python3 -m venv env

*note it is a common naming convention to name the environment env but this can be anything

In order to start the virtual environment run the script below:

source env/bin/activate

Now if you look at the project directory you will see a subdirectory env, which you just created.

Congrats! You now are working in a virtual environment and can install dependencies correctly. When you need to stop just run deactivate.

For Git users, in order to track project dependencies, continue below:

1. While in the virtual environment, start by installing a package. For this example we will use pandas. Run pip install pandas
2. Run deactivate to stop the virtual environment
3. Initialize the repo by running git init
4. Run echo ‘env' > .gitignore to include the env folder in the .gitignore file so the virtual environment is ignored in source control
5. Run pip freeze > requirements.txt to place the dependencies in a text file to be committed. Freezing reads all the installed dependencies and then produces a text file with the name of the dependency and the installed version number.
6. Run git add requirements.txt to check the file into source control.
7. Commit the files and push to a repo.

Congrats yet again! You have now properly set up your virtual environment with Git.

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