🧩 PR Commenter for GitHub & Gitea

A composite Action that posts PR comments from large output files, such as Terraform/OpenTofu plans, logs, or diffs — directly to GitHub or Gitea pull requests.

It’s based on tofu-pr-commenter but extended for Gitea compatibility, multi-line comment templates, and general-purpose content handling (not just diffs).

---

🚀 Features

• ✅ Works with GitHub and Gitea PR APIs
• ✅ Handles large text outputs (plans, diffs, logs, etc.)
• ✅ Allows multiline comment templates with placeholders
• ✅ Defaults to environment variables from the Action runner (no hardcoded repo info required)
• ✅ Can run on both GitHub Actions and Gitea Actions

---

⚙️ Inputs

Name	Required	Default	Description
platform	❌	github	Platform type (github or gitea)
token	✅	—	Access token for API requests (GITHUB_TOKEN or personal token)
pr_index	✅	—	Pull request number or index
repo_owner	❌	${{ github.repository_owner }}	Repository owner
repo_name	❌	${{ github.repository }}	Repository name
api_url	❌	${{ github.api_url }}	API URL for Gitea (required only for Gitea)
content	❌	—	Large text input — diff, plan, or log content
comment_template	❌	See below	Comment body template supporting {line} and {lines} placeholders

🧠 Template Variables

Placeholder	Description
{line}	The specific line being commented on (when parsed from diff-style input)
{lines}	The full set of added lines for that file or section

---

🧩 Default comment_template

comment_template: |
  Auto-comment:
  ---
  {line}

💡 Example: GitHub Action Workflow

name: Comment Terraform Plan on PR
on:
  pull_request:
    branches:
      - main

jobs:
  plan-comment:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4

      - name: Run Terraform Plan
        id: plan
        run: |
          terraform plan -no-color > plan.txt
          echo "plan_text<<EOF" >> $GITHUB_OUTPUT
          cat plan.txt >> $GITHUB_OUTPUT
          echo "EOF" >> $GITHUB_OUTPUT

      - name: Comment Plan on GitHub PR
        uses: "https://gitea.example.com/your-org/pr-commenter-action@main"
        with:
          platform: github
          token: ${{ secrets.GITHUB_TOKEN }}
          pr_index: ${{ github.event.pull_request.number }}
          content: ${{ steps.plan.outputs.plan_text }}
          comment_template: |
            🚀 **Terraform Plan Summary**
            ```
            {lines}
            ```

💡 Example: Gitea Action Workflow

name: Comment Plan on PR (Gitea)
on:
  pull_request:
    branches:
      - main

jobs:
  plan-comment:
    runs-on: ubuntu-latest
    steps:
      - name: Checkout
        uses: actions/checkout@v4

      - name: Run Tofu Plan
        id: tofu
        run: |
          tofu plan -no-color > tofu-plan.txt
          echo "plan_text<<EOF" >> $GITEA_OUTPUT
          cat tofu-plan.txt >> $GITEA_OUTPUT
          echo "EOF" >> $GITEA_OUTPUT

      - name: Post Plan to Gitea PR
        uses: "https://gitea.example.com/your-org/pr-commenter-action@main"
        with:
          platform: gitea
          token: ${{ secrets.GITEA_TOKEN }}
          api_url: "https://gitea.example.com/api/v1"
          pr_index: ${{ gitea.event.pull_request.number }}
          content: ${{ steps.tofu.outputs.plan_text }}
          comment_template: |
            🧠 **OpenTofu Plan Diff**
            ```
            {lines}
            ```

🪵 Example: Posting Large Log Output

- name: Upload build logs to PR
  uses: "https://gitea.example.com/your-org/pr-commenter-action@main"
  with:
    platform: gitea
    token: ${{ secrets.GITEA_TOKEN }}
    api_url: "https://gitea.example.com/api/v1"
    pr_index: 42
    content: ${{ steps.build.outputs.log }}
    comment_template: |
      🧾 **Build Log Summary**
      ```
      {lines}
      ```

🧰 Local Development

You can test the script locally by exporting the necessary environment variables and running:

export PLATFORM=gitea
export TOKEN=<your_token>
export REPO_OWNER=your-org
export REPO_NAME=your-repo
export PR_INDEX=42
export API_URL=https://gitea.example.com/api/v1
export CONTENT="$(cat plan.txt)"
python3 comment_pr.py

⚠️ Limitations & Tips for Large Files

1. GitHub & Gitea Comment Limits

   • GitHub: max ~65,536 characters per comment.
   • Gitea: may vary depending on server configuration.

2. Chunk Large Content

   • For extremely long plans/logs, split content into smaller chunks and post multiple comments.
   • Example using shell split:

split -l 5000 plan.txt plan_chunk_
for file in plan_chunk_*; do
  CONTENT=$(cat "$file")
  python3 comment_pr.py ...
done

3. Diff Parsing

   • If your content is a diff, {line} and {lines} placeholders work.
   • Otherwise, the action will post the entire content under {lines}.

4. Avoid Passing Huge Strings via Env Variables

   • Always prefer writing output to a file and reading it in the script.