Lab: Event - Discussion Comment

Introduction

In this lab, you will create a GitHub Actions workflow that reacts when someone comments on a GitHub Discussion. You will also use the contains function to conditionally run logic based on the comment’s content and demonstrate how to restrict workflow permissions for better security.

Estimated Duration: 25–30 minutes

Instructions

Step 1: Prepare your repository

Ensure that GitHub Discussions is enabled in your repository:

  1. Navigate to your repository on GitHub.
  2. Click Settings > General.
  3. Under Features, ensure Discussions is checked.

Step 2: Create the workflow

  1. In your repository, click the Code tab.

  2. Create a new workflow file:

    • Path: .github/workflows/event-discussion-comment.yml
    • File content:
    name: Event - Discussion Comment

on:
  discussion_comment:
    types: [created]

permissions:
  contents: read
  discussions: read

jobs:
  check-comment:
    runs-on: ubuntu-latest
    steps:
      - name: Log comment
        run: echo "Comment: $"

      - name: Check for keyword in comment
        if: contains(github.event.comment.body, 'urgent')
        run: echo "This comment is marked as URGENT!"

      - name: Check for unauthorized keyword
        if: contains(github.event.comment.body, 'shutdown')
        run: |
          echo "::warning::Detected sensitive keyword 'shutdown'. Manual review recommended."

  3. Commit the file to the main branch.

Step 3: Trigger the workflow

  1. Go to the Discussions tab.
  2. Open any existing discussion or create a new one.
  3. Add a comment that contains the word urgent or shutdown.

Example comments:

Step 4: View the workflow output

  1. Click the Actions tab.
  2. Open the latest run of Handle Discussion Comments.

  3. Review the logs under each step:

    • See the full comment body.
    • Observe if the urgent message is logged.
    • See a warning if shutdown is detected.

Explanation of Key Concepts

1. discussion_comment Event

2. contains Function

Used for conditional logic based on strings:

if: contains(github.event.comment.body, 'urgent')

3. permissions

Restrict workflow token scope:

permissions:
  contents: read
  discussions: read

This ensures the workflow can’t modify content or discussions—only read access is allowed.

Summary

In this lab, you created a workflow that responds to new discussion comments, uses conditional logic based on comment content, and demonstrates scoped GitHub token permissions. This sets the foundation for building more secure and context-aware workflows in collaborative projects.

Additional Resources