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Manuals / CI/CD Pipelines / Ch 3

A · FoundationsBeginner55 min read

3. First GitHub Actions workflow

CI/CD Pipelines · 48 pages source format

YAML workflow: on trigger, jobs, steps, runs-on. Install, test, fail loud on red.

What you'll learn

  • Workflow structure
  • Triggers
  • Jobs and steps
  • Action marketplace

Hello workflow

on: push, jobs.test, runs-on: ubuntu-latest, steps: checkout, setup, run tests.

name: CI
on:
  push:
    branches: [main]
  pull_request:
    branches: [main]
jobs:
  test:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
      - uses: actions/setup-node@v4
        with:
          node-version: "20"
      - run: npm ci
      - run: npm test

Do this now

Add .github/workflows/ci.yml. Push. See green check on commit.

Clear?

pull_request trigger

Same workflow on PR shows checks before merge. This is the daily loop.

Do this now

Open PR with trivial change. Confirm check runs on PR.

Clear?

Read workflow logs

Expand steps, find failure line, re-run failed jobs. Triage skill #1.

Do this now

Break a test intentionally. Read log. Fix. Re-run.

Clear?

Action versioning

Pin major version: actions/checkout@v4. Avoid @main for supply chain stability.

Do this now

Audit workflow — all actions use version tags.

Clear?

Checklist