CI/CD Pipelines

Continuous Integration (CI) is "Merge often, test automatically." Continuous Deployment (CD) is "Ship to production automatically."

The Pipeline Anatomy

A standard pipeline has three distinct stages:

1. The Build Stage (CI)

Fast feedback. Runs on every Pull Request.

• Lint: Check code style (Prettier/ESLint).
• Test: Run Unit Tests.
• Build: Compile the code / Build the Docker Image.
• Outcome: A "Green" checkmark on GitHub.

2. The Delivery Stage (CD - Staging)

Runs on merge to main.

• Push: Upload Docker image to ECR/DockerHub.
• Deploy: Update the Staging environment (Helm upgrade / Terraform apply).
• Verify: Run Integration/Smoke tests against the live Staging URL.

3. The Release Stage (CD - Prod)

• Gate: Manual approval button (optional) or automated Canary check.
• Deploy: Update Production.

GitHub Actions Pattern

Don't copy-paste YAML across 50 repos. Use Reusable Workflows.

Central Repo (infra-modules): /.github/workflows/build-node.yml -> Defines the standard npm install && npm test logic.

App Repo:

jobs:
  ci:
    uses: my-org/infra-modules/.github/workflows/build-node.yml@v1
    with:
      node-version: 18

Trunk-Based Development

Stop using GitFlow (Develop/Release branches). It's too slow.

• The Rule: Everyone pushes to main (or short-lived feature branches merging to main daily).
• The Safety: Use Feature Flags. You can merge unfinished code to main if it is wrapped in if (flags.newCheckout). It sits in Prod, dormant, until you flip the switch.