Chapter 26: CI/CD Workflow

We configure the robot using YAML (Yet Another Markup Language). It's just key-value pairs, like JSON but without brackets.

26.1 Anatomy of a Workflow File

File: .github/workflows/go-check.yml

name: Go Check                # 1. The Name of the Workflow
on: [push, pull_request]      # 2. Even Triggers

jobs:
  test:                       # 3. The Job Name
    runs-on: ubuntu-latest    # 4. The Computer (Runner)
    steps:
      - uses: actions/checkout@v3  # 5. Step: Download Code
      - uses: actions/setup-go@v4  # 6. Step: Install Go
        with:
          go-version: '1.21'
      - name: Test
        run: go test ./...    # 7. Step: Run Command

Breaking it Down

1. on: When should the robot wake up? (On every Push).
2. runs-on: GitHub gives us a free computer running Ubuntu Linux.
3. uses: These are pre-made scripts ("Actions") written by others.
   • checkout: Downloads your repository.
   • setup-go: Installs the Go compiler.
4. run: This executes a command in the terminal of that Linux computer.

26.2 "Green Build"

If go test exits with code 0 (Success), the build is Green. If it exits with 1 (Error), the build is Red, and GitHub turns the Merge Button grey (if configured). This saves you from breaking the Main branch.

26.3 The Identity Card (Favicon)

You might notice a small image in your browser tab. That is the Favicon.

• Think of it as: An ID Card.
• Without it: Your site looks like a stranger.
• With it: Your site has an identity.

In our docs, we configure it in config.mjs:

head: [['link', { rel: 'icon', href: '/gopher.png' }]]

This tells the browser: "When you see my site, show this picture."

🎓 Knowledge Check: What does a "Green Build" mean in CI/CD?

Answer: It means the robot ran all your tests, and they passed (Exit Code 0). Ideally, you should only merge code to main if the build is Green.