DevOps CI/CD Patterns

DevOps CI/CD Patterns

Core Principles

1. Automate Everything — Every step from linting to deployment should be codified in pipeline configuration. Manual steps introduce drift and human error.
2. Fast Feedback Loops — Developers should know within minutes whether their change broke something. Prioritize quick checks early in the pipeline.
3. Reproducibility — Builds must produce identical artifacts given the same inputs. Pin dependency versions, use immutable base images, and avoid relying on ambient state.
4. Fail Fast, Fail Loud — Place the cheapest and most likely-to-fail checks first. Notify the right people immediately on failure.
5. Security as a First-Class Concern — Secrets must never appear in logs, artifacts, or version control. Scope credentials to the narrowest permission set possible.

GitHub Actions Fundamentals

Workflows live in .github/workflows/ and are triggered by repository events. Structure jobs to maximize parallelism while respecting dependency ordering.

# .github/workflows/ci.yml
name: CI Pipeline
on:
  push:
    branches: [main]
  pull_request:
    branches: [main]

jobs:
  lint:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
      - uses: actions/setup-node@v4
        with:
          node-version: 20
          cache: npm
      - run: npm ci
      - run: npm run lint

  test:
    runs-on: ubuntu-latest
    needs: lint
    strategy:
      matrix:
        node-version: [18, 20, 22]
    steps:
      - uses: actions/checkout@v4
      - uses: actions/setup-node@v4
        with:
          node-version: ${{ matrix.node-version }}
          cache: npm
      - run: npm ci
      - run: npm test

See github-actions-patterns for: workflow triggers, matrix builds, reusable workflows, and composite actions.

GitLab CI Patterns

GitLab CI uses a .gitlab-ci.yml file at the repository root. Stages define the execution order, and jobs within the same stage run in parallel by default.