Lesson 4. CI/CD and Automation in HAPI#

Why This Matters#

When a team works on a project, it’s important to automate routine tasks: code checking, building, publishing. HAPI uses GitHub Actions — GitHub’s built-in automation system — for this purpose.

CI/CD (Continuous Integration / Continuous Delivery) is the practice of automatically checking and building code with every change.

GitHub Actions is a GitHub service that runs tasks automatically on certain events (e.g., when someone pushes code or creates a pull request).

What Automations HAPI Has#

In the .github/workflows/ directory, there are 6 files — each describes one automation:

1. 🧪 Tests (test.yml)#

When it runs: on every push and pull request.

What it does:

1. Checks out the code
2. Installs Bun
3. Installs dependencies (bun install)
4. Checks types (bun typecheck)
5. Runs tests (bun run test)

Why: to make sure new code didn’t break anything.

2. 🤖 AI PR Review (codex-pr-review.yml)#

PR (Pull Request) is a request to add changes to the project. Other members review the code before accepting.

When it runs: when a new PR is opened or a PR is moved from draft to ready.

What it does:

• The Codex AI model (GPT-5.2) automatically reviews code in the PR
• Leaves a comment with remarks and recommendations
• Doesn’t review PRs from bots or PRs with the bot-skip label
• Doesn’t duplicate reviews — if the bot already left a comment, it won’t run again

Why: speeds up code review and catches common errors.

3. 💬 Auto-response to Issues (issue-auto-response.yml)#

Issue is a ticket/task in the repository: bug report, feature request, question.

When it runs: when a new issue is created or a label is added.

What it does:

• Codex analyzes the issue and responds automatically
• Skips duplicates (duplicate), spam (spam), and issues with the bot-skip label
• Responds only once

Why: users get a first response faster, and developers don’t need to answer typical questions.

4. 🗣️ Responses to Mentions (codex-mention-response.yml)#

When it runs: when someone mentions @tiann in a comment.

What it does:

• Codex responds to the question or comment
• Only works for users with write access
• Doesn’t respond to its own comments or issues with the bot-skip label

Why: quick help for developers right in the discussion.

5. 📦 Release (release.yml)#

A release is publishing a new version of the software.

When it runs: when a new version tag is created (e.g., v1.2.3).

What it does:

1. Builds binary files for all platforms
2. Packages into archives (.tar.gz for macOS/Linux, .zip for Windows)
3. Calculates checksums
4. Creates a GitHub release with downloadable files
5. Updates the Homebrew formula (package manager for macOS)

6. 🌐 Web App Deploy (webapp.yml)#

Deploy is placing an application on a server so it becomes available to users.

When it runs: when changes are made to the web/ directory in the main branch.

What it does:

1. Builds the web application
2. Publishes to GitHub Pages (free hosting from GitHub)
3. Available at app.hapi.run

How It All Connects#

Developer makes changes
         │
         ├─► Push to any branch
         │       └─► test.yml: code checks and tests
         │
         ├─► Opens a PR
         │       └─► codex-pr-review.yml: AI reviews code
         │
         ├─► PR merged to main + changes in web/
         │       └─► webapp.yml: website update
         │
         ├─► Creates tag v1.2.3
         │       └─► release.yml: build + publish
         │
         └─► New issue or comment
                 └─► issue-auto-response.yml / codex-mention-response.yml

The bot-skip Label#

If you don’t want the bot to respond to a specific issue or PR, add the bot-skip label. All AI automations check this label and skip such tasks.

Lesson Summary#

• HAPI uses 6 automations via GitHub Actions for routine tasks
• Tests run automatically with every code change
• AI (Codex) automatically reviews PRs, responds to issues and comments
• Releases are built for all platforms with a single command when a tag is created
• The web application is automatically published on changes
• The bot-skip label disables AI automations for a specific task