Changelog Summarizer

A GitHub Action that uses ChatGPT to summarize commit messages and generate changelogs for pull requests (PRs).

Features

• Summarizes individual commits in a PR and posts them as a comment.

• Generates an overall summary and updates a changelog file (e.g., CHANGELOG.md) when the PR is merged.

• Includes commit hashes for tracking in summaries.

• Open-source and reusable by anyone with a ChatGPT API key.

Prerequisites

• An OpenAI API key (get one from OpenAI).

• A GitHub repository where you want to use this action.

Usage

To integrate changelog-summarizer into your GitHub repository, follow these steps:

1. Add the Action to Your Repository

Add the following workflows to your repository in the .github/workflows/ directory.

Workflow 1: Summarize Commits

This workflow runs when a PR is opened or updated, summarizing commits and posting them as a PR comment.

.github/workflows/summarize-commits.yml:

name: Summarize Commits
on:
  pull_request:
    types: [opened, synchronize]
permissions:
  pull-requests: write
  contents: read
jobs:
  summarize:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v3
      - uses: nsnguyen/changelog-summarizer@v1
        with:
          mode: summarize_commits
          api-key: ${{ secrets.CHATGPT_API_KEY }}
          github-token: ${{ github.token }}

Workflow 2: Update Changelog

This workflow runs when a PR is merged, generating an overall summary and updating CHANGELOG.md.

.github/workflows/update-changelog.yml:

name: Update Changelog
on:
  pull_request:
    types: [closed]
permissions:
  pull-requests: read
  contents: write
jobs:
  update:
    if: github.event.pull_request.merged == true
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v3
        with:
          ref: ${{ github.event.pull_request.base.ref }}
      - uses: nsnguyen/changelog-summarizer@v1
        with:
          mode: generate_changelog
          api-key: ${{ secrets.CHATGPT_API_KEY }}
          github-token: ${{ github.token }}
          changelog-file: CHANGELOG.md

2. Set Up Secrets

• Go to your repository on GitHub > Settings > Secrets and variables > Actions > New repository secret.

• Add a secret named CHATGPT_API_KEY with your OpenAI API key value.

• Ensure the API key has sufficient quota for ChatGPT API calls.

3. Customize (Optional)

• Change the Changelog File: Modify the changelog-file input in update-changelog.yml to use a different file path (e.g., docs/CHANGELOG.md).

• Adjust Summary Format: If you want to customize how summaries are generated, fork this repository, modify src/index.js (e.g., change the ChatGPT prompt), rebuild with npm run build, and tag a new version (e.g., v2).

Updating the Action

To keep your repository up-to-date with new versions of changelog-summarizer:

1. Check the Releases page for new versions (e.g., v2, v3).

2. Update the version in your workflows by changing nsnguyen/changelog-summarizer@v1 to the latest version (e.g., nsnguyen/changelog-summarizer@v2).

3. Test the updated workflows in a PR to ensure compatibility with your repository.

Example Output

PR Comment (Workflow 1)

### Commit Summaries
<!-- COMMIT_SUMMARIES_START -->
- This commit adds a final test Python file to the project. (Commit: abc123def)
- This commit improves the final test Python file. (Commit: xyz789ghi)
<!-- COMMIT_SUMMARIES_END -->

_Automatically updated by changelog-summarizer._

CHANGELOG.md (Workflow 2)

# Changelog

## [2025-02-20] PR #3: Add and improve final test Python file
- Enhanced the project with a final test Python file and improvements

Notes

• This action uses ChatGPT API calls, which may incur costs based on usage (see OpenAI pricing).

• Ensure your GITHUB_TOKEN has the necessary permissions (pull-requests: write, contents: read/write) as specified in the workflows.

• The action requires Node.js 16 or later (bundled in GitHub Actions runners).