Example of Using Pre-Commit Hooks

Example repository for article on setting up pre-commit hooks.

Requirements

Python >= 3.8

Setup

NOTE: If you choose to use GitHub Codespaces with this repository, you can skip ahead to step 4.

1. Clone this repository and change to the directory for this repository:

   git clone git@github.com:stefmolin/pre-commit-example.git && \
       cd pre-commit-example;

2. Create a virtual environment:

   python -m venv venv

3. Activate the virtual environment:

   # bash/zsh
   source venv/bin/activate
   
   # Windows cmd.exe
   .\venv\Scripts\activate.bat

4. Install the package (update pip if you encounter errors):

   python -m pip install -e .

5. Install the pre-commit hooks in this repository:

   pre-commit install

6. Create the file src/example/utils.py as follows and save it:

   import re
   
   def my_function(a):
       """My function."""
       pass

7. Try to commit this file:

   git add src/example/utils.py
   git commit -m "Add utils.py"

   The pre-commit hooks will run, and your commit will be stopped since there are some violations:

   

8. Fix those issues (example below) and then try to commit again.

   """Utility functions."""
   
   
   def my_function(a):
       """
       My function.
   
       Parameters
       ----------
       a : int
           The value to use.
       """
       pass

   If you fixed everything, your commit will be successful:

   

For an explanation of the setup, please consult the accompanying article.

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About the Author

Stefanie Molin (@stefmolin) is a software engineer and data scientist at Bloomberg in New York City, where she tackles tough problems in information security, particularly those revolving around data wrangling/visualization, building tools for gathering data, and knowledge sharing. She is also the author of Hands-On Data Analysis with Pandas, which is currently in its second edition and has been translated into Korean. She holds a bachelor’s of science degree in operations research from Columbia University's Fu Foundation School of Engineering and Applied Science, as well as a master’s degree in computer science, with a specialization in machine learning, from Georgia Tech. In her free time, she enjoys traveling the world, inventing new recipes, and learning new languages spoken among both people and computers.