Automating Python Code Linting with GitHub Actions

Linting your Python code is crucial to maintaining code quality and consistency across your projects. GitHub Actions provides a powerful way to automate linting processes, ensuring that all code changes meet coding standards before being merged into your repository.

In this article, we will explore how to set up a GitHub Action to lint Python code automatically whenever a pull request is created.

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Prerequisites

To follow along, ensure you have the following:

• A GitHub repository containing Python code.
• Basic knowledge of GitHub Actions and workflows.

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Setting Up the GitHub Action Workflow

Below is a GitHub Actions workflow configuration that automatically lints Python code in pull requests.

name: Lint Python Code

on:
  pull_request:
    paths:
      - '**/*.py'  # Trigger workflow only when Python files change

jobs:
  lint:
    name: Lint Code
    runs-on: ubuntu-latest

    steps:
      - name: Check out code
        uses: actions/checkout@v2

      - name: Get changed Python files
        id: get_changed_files
        uses: tj-actions/changed-files@v35
        with:
          files: '**/*.py'

      - name: Run pylint
        if: steps.get_changed_files.outputs.any_changed == 'true'
        uses: dciborow/action-pylint@0.1.0
        with:
          github_token: ${{ secrets.GITHUB_TOKEN }}
          reporter: github-pr-review
          glob_pattern: ${{ steps.get_changed_files.outputs.all_changed_files }}
          level: warning
          filter_mode: added
          fail_on_error: true

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Explanation of the Workflow

1. Triggering the workflow:

   • The workflow runs on pull_request events.
   • It is triggered only if changes include Python files ('**/*.py').

2. Steps in the job:

   • Checkout code: Retrieves the repository code.
   • Identify changed Python files: Uses tj-actions/changed-files to detect which Python files were modified.
   • Run pylint:
     • The dciborow/action-pylint GitHub Action runs pylint on the changed files.
     • It reports warnings directly on the pull request.
     • The workflow fails if pylint finds any errors.

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Customization Options

You can customize the workflow based on your needs:

• Modify the pylint_args to include or exclude specific checks.
• Change the fail_on_error value to false if you want warnings but don't want to block merges.
• Use a different pylint reporter such as github-checks instead of github-pr-review.

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Viewing Linting Results

Once the pull request is created, the pylint report will appear as a review comment on the PR, helping developers identify and fix issues efficiently.

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Conclusion

By automating Python code linting with GitHub Actions, you ensure that your codebase remains clean and adheres to coding standards, reducing technical debt and improving maintainability. Try integrating this workflow into your projects today!