GitHub Actions: From First Workflow to Reusable

GitHub Actions in 30 minutes: enough to ship; the reusable pattern is what scales it across an org.

Step 1: First workflow

# .github/workflows/ci.yml
on: [push]
jobs:
  test:
    runs-on: ubuntu-latest
    steps:
      - run: echo "hello"

Step 2: Real CI

• Add: checkout, setup-node, npm install, npm test.
• Configure caching for node_modules.

Step 3: Make it reusable

Refactor: workflow_call trigger; inputs for variation.

Move to a shared repo; tag the version.

Step 4: Consume from other repos

jobs:
  ci:
    uses: org/shared-ci/.github/workflows/ci.yml@v1
    with:
      node-version: 20

One source of truth; many consumers.

Antipatterns

• Copy-pasted workflows across 50 repos. Drift.
• Pinning to @main. Surprise breakage.
• Reusable workflow as 100% rigid. Inputs allow flexibility.

What to do this week

Three moves. (1) Run the tutorial end-to-end on your own laptop / sandbox. (2) Apply the pattern to one production workload. (3) Document the variations you needed; share with the team.