celguard 🛡️

A GitHub Action that validates Pull Requests using Common Expression Language (CEL).

It reads rules from .github/celguard.yaml and ensures your PR title, body, branch, labels, etc. follow your team's conventions.

✨ Features

• 🔍 CEL-based rules — powerful and flexible expression syntax (regex, list operations, logic)
• ⚙️ Custom config per repo — define rules in .github/celguard.yaml
• 🧪 Go implementation — single binary, so fast

🚀 Quick Start

1. Create Configuration File

Create .github/celguard.yaml in your repository root.

title:
  cel: "value.matches('^(feat|fix|docs|style|refactor|test|chore): .+')"
  error: PR title must follow conventional commits format
head_ref:
  cel: "!value.matches('^(main|master|develop)$')"
  error: Direct commits to main/master/develop are not allowed
labels:
  cel: "value.exists(l, l in ['bug', 'enhancement', 'documentation'])"
  error: At least one of [bug, enhancement, documentation] label is required

2. Add Workflow

Create .github/workflows/celguard.yaml.

name: PR Lint
on:
  pull_request:
    types: [opened, reopened, edited]

permissions:
  contents: read
  pull-requests: write

jobs:
  celguard:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
      - name: Run PR Lint
        uses: konojunya/celguard@v1

📖 Configuration

Supported Configuration Keys

You can define validation rules for the following keys:

Key	Type	Description	Example
title	string	PR title	"feat: add new feature"
body	string	PR body	"This PR adds..."
author	string	PR author's GitHub username	"konojunya"
base_ref	string	Base branch name	"main"
head_ref	string	Head branch name (source branch of PR)	"feature/new-feature"
labels	[]string	Array of labels attached to PR	["bug", "enhancement"]

Configuration File Format

For each key, define rules in the following format:

<key>:
  cel: <CEL expression>
  error: <error message>

• cel: CEL expression. The validation passes when this expression returns true
• error: Error message displayed when validation fails (optional)

🛠️ Development

Testing

go test ./...

🤝 Contributing

Contributions are welcome! You can contribute by following these steps:

1. Fork this repository
2. Create a feature branch (git checkout -b feature/amazing-feature)
3. Commit your changes (git commit -m 'Add some amazing feature')
4. Push to the branch (git push origin feature/amazing-feature)
5. Open a Pull Request

Contribution Guidelines

• Bug reports and feature requests are welcome in Issues
• Code changes should be submitted via Pull Request
• Please follow the existing code style
• When adding new features, please also add tests

📄 License

This project is licensed under the license specified in the LICENSE file.