Github Actions

GitHub Actions Best Practices

Workflow Structure

# .github/workflows/ci.yml
name: CI

on:
    push:
        branches: [main]
    pull_request:
        branches: [main]

concurrency:
    group: ${{ github.workflow }}-${{ github.ref }}
    cancel-in-progress: true

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
        steps:
            - uses: actions/checkout@v4
            - uses: actions/setup-node@v4
              with:
                  node-version: 20
                  cache: "npm"
            - run: npm ci
            - run: npm test

Key Principles

• Always set concurrency with cancel-in-progress: true on PR workflows — avoids wasting runners on outdated commits.
• Pin action versions to a major tag (@v4) or full SHA for security-critical actions. Never use @main or @latest.
• Use npm ci (or pnpm install --frozen-lockfile) instead of npm install — ensures deterministic installs from the lockfile.

Caching

Node.js Dependencies

The built-in cache in actions/setup-node handles most cases:

- uses: actions/setup-node@v4
  with:
      node-version: 20
      cache: "npm" # or "pnpm" or "yarn"

Custom Caching

For build outputs, Playwright browsers, or other artifacts:

- uses: actions/cache@v4
  with:
      path: |
          .next/cache
          node_modules/.cache
      key: ${{ runner.os }}-build-${{ hashFiles('**/package-lock.json') }}
      restore-keys: |
          ${{ runner.os }}-build-

Turbo Cache

For Turborepo monorepos:

- uses: actions/cache@v4
  with:
      path: .turbo
      key: ${{ runner.os }}-turbo-${{ github.sha }}
      restore-keys: |
          ${{ runner.os }}-turbo-

Parallel Jobs

Split independent checks into separate jobs for faster feedback:

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

    typecheck:
        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 typecheck

    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 test

    build:
        needs: [lint, typecheck, 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 build

Use needs to gate deployment on all checks passing.

Matrix Builds

Test across multiple versions or platforms:

jobs:
    test:
        runs-on: ${{ matrix.os }}
        strategy:
            matrix:
                os: [ubuntu-latest, macos-latest]
                node-version: [18, 20, 22]
            fail-fast: false
        steps:
            - uses: actions/checkout@v4
            - uses: actions/setup-node@v4
              with:
                  node-version: ${{ matrix.node-version }}
                  cache: "npm"
            - run: npm ci
            - run: npm test

• Set fail-fast: false to run all combinations even if one fails.
• Use include and exclude to fine-tune the matrix.

Reusable Workflows

Extract common workflow patterns into callable workflows:

# .github/workflows/reusable-ci.yml
name: Reusable CI

on:
    workflow_call:
        inputs:
            node-version:
                type: number
                default: 20
        secrets:
            NPM_TOKEN:
                required: false

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

Call it from another workflow:

# .github/workflows/ci.yml
jobs:
    ci:
        uses: ./.github/workflows/reusable-ci.yml
        with:
            node-version: 20
        secrets: inherit

• Use workflow_call trigger for reusable workflows.
• secrets: inherit passes all secrets from the caller.
• Reusable workflows can live in the same repo or a shared org repo.

Composite Actions

Bundle repeated steps into a single reusable action:

# .github/actions/setup-project/action.yml
name: "Setup Project"
description: "Checkout, setup Node, and install dependencies"
inputs:
    node-version:
        description: "Node.js version"
        default: "20"
runs:
    using: "composite"
    steps:
        - uses: actions/checkout@v4
          shell: bash
        - uses: actions/setup-node@v4
          with:
              node-version: ${{ inputs.node-version }}
              cache: "npm"
          shell: bash
        - run: npm ci
          shell: bash

Use in any workflow:

steps:
    - uses: ./.github/actions/setup-project
      with:
          node-version: 20
    - run: npm test

When to Use Each

Secrets and Security

• Never hardcode secrets — use ${{ secrets.SECRET_NAME }}.
• Use environment protection rules for production deployments (require approvals, limit branches).
• Minimize permissions with the permissions key:

permissions:
    contents: read
    pull-requests: write

• Audit third-party actions before using them. Pin to a full SHA for critical workflows:

- uses: actions/checkout@b4ffde65f46336ab88eb53be808477a3936bae11 # v4.1.1

• Use ${{ github.token }} (auto-provisioned) instead of personal access tokens when possible.

Environment-Based Deployments

jobs:
    deploy-staging:
        runs-on: ubuntu-latest
        environment: staging
        steps:
            - uses: actions/checkout@v4
            - run: npm ci && npm run build
            - run: npx deploy --env staging

    deploy-production:
        needs: deploy-staging
        runs-on: ubuntu-latest
        environment:
            name: production
            url: https://myapp.com
        steps:
            - uses: actions/checkout@v4
            - run: npm ci && npm run build
            - run: npx deploy --env production

Configure environment protection rules in GitHub settings to require manual approval before production deploys.

Path Filtering

Run workflows only when relevant files change:

on:
    push:
        paths:
            - "src/**"
            - "package.json"
            - "package-lock.json"
        paths-ignore:
            - "docs/**"
            - "**.md"

For monorepos, use path filters to run only affected package checks.

Artifacts

Share files between jobs:

jobs:
    build:
        runs-on: ubuntu-latest
        steps:
            - uses: actions/checkout@v4
            - run: npm ci && npm run build
            - uses: actions/upload-artifact@v4
              with:
                  name: build-output
                  path: dist/
                  retention-days: 1

    deploy:
        needs: build
        runs-on: ubuntu-latest
        steps:
            - uses: actions/download-artifact@v4
              with:
                  name: build-output
                  path: dist/
            - run: npx deploy dist/

Set retention-days to avoid accumulating large artifacts.

Common Patterns

PR Preview Deploys

on:
    pull_request:
        types: [opened, synchronize]

jobs:
    preview:
        runs-on: ubuntu-latest
        permissions:
            pull-requests: write
        steps:
            - uses: actions/checkout@v4
            - run: npm ci && npm run build
            - id: deploy
              run: echo "url=$(npx deploy --preview)" >> $GITHUB_OUTPUT
            - uses: actions/github-script@v7
              with:
                  script: |
                      github.rest.issues.createComment({
                        issue_number: context.issue.number,
                        owner: context.repo.owner,
                        repo: context.repo.repo,
                        body: `Preview deployed: ${{ steps.deploy.outputs.url }}`
                      })

Scheduled Jobs

on:
    schedule:
        - cron: "0 9 * * 1" # Every Monday at 9am UTC

jobs:
    dependency-audit:
        runs-on: ubuntu-latest
        steps:
            - uses: actions/checkout@v4
            - run: npm audit --production

Release on Tag

on:
    push:
        tags:
            - "v*"

jobs:
    release:
        runs-on: ubuntu-latest
        permissions:
            contents: write
        steps:
            - uses: actions/checkout@v4
            - uses: actions/setup-node@v4
              with:
                  node-version: 20
                  registry-url: "https://registry.npmjs.org"
            - run: npm ci && npm run build
            - run: npm publish
              env:
                  NODE_AUTH_TOKEN: ${{ secrets.NPM_TOKEN }}
            - uses: softprops/action-gh-release@v2
              with:
                  generate_release_notes: true

Debugging

• Enable debug logging: Set the ACTIONS_RUNNER_DEBUG repository secret to true.
• Use act for local testing: act push simulates a push event locally.
• Add diagnostic steps when debugging:

- run: |
      echo "Event: ${{ github.event_name }}"
      echo "Ref: ${{ github.ref }}"
      echo "SHA: ${{ github.sha }}"
      echo "Actor: ${{ github.actor }}"

Anti-Patterns

• Don't install dependencies in every job without caching — use actions/setup-node with cache or a composite setup action.
• Don't use @master or @main for action versions — pin to a tagged release.
• Don't store secrets in workflow files or commit them to the repo.
• Don't run all checks sequentially — parallelize independent jobs.
• Don't skip concurrency on PR workflows — stale runs waste minutes and can deploy outdated code.