Boost Python Code Quality with Flake8 and pre-commit: A Step-by-Step Guide

It is essential to follow code style guidelines; Python code quality checks can be divided into two approaches: static local analysis and Git‑based checks.

Static Local Detection (Flake8)

Flake8 bundles Pyflakes, pycodestyle, and McCabe and supports custom plugins. It can:

Check compliance with PEP 8

Detect syntax errors, unused variables, and unused imports

Measure code complexity

Installation

pip install flake8

Configuration

It is recommended to configure Flake8 in PyCharm. The configuration includes specifying the path to the Flake8 executable and adding custom arguments such as maximum line length or file filters.

After installation, clicking the check button runs the analysis; an exit code 0 indicates the code conforms to the standards.

pre-commit

Website: https://pre-commit.com/

pre-commit provides Git hooks that automatically run scripts during git commit. If the code fails the checks, the commit is aborted.

Functions:

Perform style checks before a commit

Automatically reformat non‑compliant code (e.g., fixing whitespace, updating imports)

Alert when code still does not meet the standards after auto‑fixes

Installation

pip install pre-commit

Configuration

Add a .pre-commit-config.yaml file at the project root. Example configuration:

repos:
- repo: https://github.com/pre-commit/pre-commit-hooks
  rev: v2.3.0
  hooks:
  - id: check-yaml
  - id: end-of-file-fixer
  - id: trailing-whitespace
- repo: https://github.com/psf/black
  rev: 19.3b0
  hooks:
  - id: black
- repo: https://github.com/pre-commit/pre-commit-hooks
  rev: v2.3.0
  hooks:
  - id: flake8
    args:
    - --max-line-length=120

After configuring, run pre-commit install to generate the hook script in .git/hooks/pre-commit. This ensures the hook is active for future commits.

Usage

With the configuration in place, every git commit triggers the defined checks. Based on the results, you can fix issues or proceed with the commit.