CI/CD Operations

Comprehensive patterns for continuous integration, delivery, and deployment using GitHub Actions, release automation tools, and testing pipelines.

GitHub Actions Quick Reference

Workflow File Anatomy

name: CI                          # Display name in Actions tab
on:                               # Trigger events
  push:
    branches: [main]
  pull_request:
    branches: [main]

permissions:                      # GITHUB_TOKEN scope (least privilege)
  contents: read
  pull-requests: write

concurrency:                      # Prevent duplicate runs
  group: ${{ github.workflow }}-${{ github.ref }}
  cancel-in-progress: true

env:                              # Workflow-level environment variables
  NODE_VERSION: "20"

jobs:
  test:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
      - uses: actions/setup-node@v4
        with:
          node-version: ${{ env.NODE_VERSION }}
          cache: npm
      - run: npm ci
      - run: npm test

Core Syntax Elements

Trigger Decision Tree

Trigger Filter Patterns

on:
  push:
    branches: [main, 'release/**']      # Branch patterns
    paths: ['src/**', '!src/**/*.test.*'] # Path filters (ignore tests)
    tags: ['v*']                          # Tag patterns
  pull_request:
    types: [opened, synchronize, reopened] # Default types
    paths-ignore: ['docs/**', '*.md']     # Ignore docs-only changes

Caching Strategies

Manual Cache Example

- uses: actions/cache@v4
  with:
    path: |
      ~/.cargo/bin
      ~/.cargo/registry
      ~/.cargo/git
      target
    key: cargo-${{ runner.os }}-${{ hashFiles('**/Cargo.lock') }}
    restore-keys: |
      cargo-${{ runner.os }}-

Matrix Strategy

strategy:
  fail-fast: false                    # Don't cancel siblings on failure
  max-parallel: 4                     # Limit concurrent jobs
  matrix:
    os: [ubuntu-latest, windows-latest, macos-latest]
    node-version: [18, 20, 22]
    include:                          # Add specific combos
      - os: ubuntu-latest
        node-version: 22
        coverage: true
    exclude:                          # Remove specific combos
      - os: windows-latest
        node-version: 18

Dynamic Matrix

prepare:
  runs-on: ubuntu-latest
  outputs:
    matrix: ${{ steps.set.outputs.matrix }}
  steps:
    - id: set
      run: echo "matrix=$(jq -c . matrix.json)" >> "$GITHUB_OUTPUT"

test:
  needs: prepare
  strategy:
    matrix: ${{ fromJson(needs.prepare.outputs.matrix) }}

Secrets Management

Secrets Best Practices

# Reference secrets - NEVER echo or log them
- run: deploy --token ${{ secrets.DEPLOY_TOKEN }}

# Mask custom values
- run: echo "::add-mask::$CUSTOM_SECRET"

# Use environments for deployment secrets
jobs:
  deploy:
    environment: production           # Requires approval + has secrets
    steps:
      - run: deploy --key ${{ secrets.PROD_API_KEY }}

OIDC for Cloud (No Stored Secrets)

permissions:
  id-token: write
  contents: read

steps:
  - uses: aws-actions/configure-aws-credentials@v4
    with:
      role-to-assume: arn:aws:iam::123456789:role/github-actions
      aws-region: us-east-1

Common Workflow Patterns

Test on Pull Request

name: Test
on:
  pull_request:
    branches: [main]
concurrency:
  group: test-${{ github.head_ref }}
  cancel-in-progress: true
jobs:
  test:
    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
      - run: npm test -- --coverage

Deploy on Merge to Main

name: Deploy
on:
  push:
    branches: [main]
jobs:
  deploy:
    runs-on: ubuntu-latest
    environment: production
    steps:
      - uses: actions/checkout@v4
      - run: npm ci && npm run build
      - run: npx wrangler deploy
        env:
          CLOUDFLARE_API_TOKEN: ${{ secrets.CF_API_TOKEN }}

Release on Tag

name: Release
on:
  push:
    tags: ['v*']
permissions:
  contents: write
jobs:
  release:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
        with: { fetch-depth: 0 }
      - run: |
          gh release create ${{ github.ref_name }} \
            --generate-notes \
            --title "${{ github.ref_name }}"
        env:
          GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}

Gotchas Table

Expression Syntax Quick Reference

Step Outputs

steps:
  - id: version
    run: echo "value=$(cat VERSION)" >> "$GITHUB_OUTPUT"

  - run: echo "Version is ${{ steps.version.outputs.value }}"

Job Outputs (for Cross-Job Communication)

jobs:
  build:
    runs-on: ubuntu-latest
    outputs:
      artifact-id: ${{ steps.upload.outputs.artifact-id }}
    steps:
      - id: upload
        run: echo "artifact-id=abc123" >> "$GITHUB_OUTPUT"

  deploy:
    needs: build
    runs-on: ubuntu-latest
    steps:
      - run: echo "Deploying ${{ needs.build.outputs.artifact-id }}"

Reference Files