openai summarize diff action

this github action receives a git diff (e.g., a pr diff) and uses openai to summarize and explain the changes made in that diff in a clear, concise way.

features

• generates concise explanations of code changes
• customizable output length and style
• easy to integrate into your ci/cd workflow
• now includes comprehensive tests and error handling

inputs

diff

required the diff to be explained.

apikey

required your openai api key. get one at openai platform.

examplepostsummary

optional an example summary to guide the model's output style. default: "update the code with new features: parallelisation, caching, and better error handling"

maxtokens

optional maximum number of tokens to generate. default: 30

maxcharacters

optional maximum characters in the generated explanation. default: 140

outputs

explanation

the explanation and summary of the diff generated by openai.

example usage

to explain the changes made in a pr

name: Explain PR Changes

on:
  pull_request:
    types: [opened, synchronize]

jobs:
  explain-diff:
    runs-on: ubuntu-latest
    steps:
      - name: Checkout code
        uses: actions/checkout@v4
        with:
          fetch-depth: 0
          
      - name: Get PR diff
        id: diff
        run: |
          git fetch origin ${{ github.event.pull_request.base.ref }}
          DIFF=$(git diff origin/${{ github.event.pull_request.base.ref }}..HEAD)
          echo "DIFF<<EOF" >> $GITHUB_ENV
          echo "$DIFF" >> $GITHUB_ENV
          echo "EOF" >> $GITHUB_ENV
          
      - name: Explain Diff
        id: explain
        uses: grey/openai-summarize-diff-action@main
        with:
          diff: ${{ env.DIFF }}
          apikey: ${{ secrets.OPENAI_API_KEY }}
          
      - name: Output explanation
        run: echo "${{ steps.explain.outputs.explanation }}"

to explain the changes and post the result as a comment in the pr

name: Explain PR Changes and Comment

on:
  pull_request:
    types: [opened, synchronize]

jobs:
  explain-diff:
    runs-on: ubuntu-latest
    permissions:
      pull-requests: write
    steps:
      - name: Checkout code
        uses: actions/checkout@v4
        with:
          fetch-depth: 0
          
      - name: Get PR diff
        id: diff
        run: |
          git fetch origin ${{ github.event.pull_request.base.ref }}
          DIFF=$(git diff origin/${{ github.event.pull_request.base.ref }}..HEAD)
          echo "DIFF<<EOF" >> $GITHUB_ENV
          echo "$DIFF" >> $GITHUB_ENV
          echo "EOF" >> $GITHUB_ENV
          
      - name: Explain Diff
        id: explain
        uses: grey/openai-summarize-diff-action@main
        with:
          diff: ${{ env.DIFF }}
          apikey: ${{ secrets.OPENAI_API_KEY }}
          
      - name: Post comment
        uses: actions/github-script@v7
        with:
          github-token: ${{ secrets.GITHUB_TOKEN }}
          script: |
            const explanation = process.env.EXPLANATION;
            github.rest.issues.createComment({
              issue_number: context.issue.number,
              owner: context.repo.owner,
              repo: context.repo.repo,
              body: `## 🤖 AI Summary of Changes\n\n${explanation}`
            });
        env:
          EXPLANATION: ${{ steps.explain.outputs.explanation }}

local development

setup

1. clone the repository:

   git clone https://github.com/your-username/openai-summarize-diff-action.git
   cd openai-summarize-diff-action

2. install dependencies:

   npm install

3. create a .env file with your openai api key:

   OPENAI_API_KEY=your_api_key_here
   

testing

run tests:

npm test

run tests with coverage:

npm run test:coverage

run tests in watch mode (useful during development):

npm run test:watch

linting

run linting:

npm run lint

building

build the action:

npm run build

this will run linting, tests, and then build the action into the dist directory.

manual testing

you can test the action locally by creating a test script:

// test-local.js
require('dotenv').config();
const { generateDiffExplanation } = require('./src/openai');

async function test() {
  const diff = `diff --git a/file.js b/file.js
index 123..456 789
--- a/file.js
+++ b/file.js
@@ -1,3 +1,4 @@
 const a = 1;
+const b = 2;
 const c = 3;`;

  try {
    const explanation = await generateDiffExplanation({
      diff,
      apiKey: process.env.OPENAI_API_KEY,
      maxTokens: 50,
      maxCharacters: 200
    });
    
    console.log('Explanation:', explanation);
  } catch (error) {
    console.error('Error:', error.message);
  }
}

test();

run the test script:

node test-local.js

notes

• this action uses openai's gpt-4o-mini model by default.
• make sure to store your openai api key as a secret in your repository settings.
• the action will ignore library folders to focus on meaningful code changes.

license

mit