github-actions

name	github-actions
description	Provides patterns for building fast, reliable CI/CD workflows with GitHub-hosted runners including workflow syntax, caching, secrets, and reusable workflows.

GitHub Actions

Fast, reliable CI/CD workflows with GitHub-hosted runners. Core patterns for building production pipelines.

Sources: GitHub Actions Documentation (docs.github.com/en/actions), GitHub Actions Best Practices

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Workflow Syntax

Define workflows in .github/workflows/*.yml. Triggered by push, pull_request, schedule, or manual dispatch.

name: CI
on: [push, pull_request]

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 && npm test

Reference: https://docs.github.com/en/actions/using-workflows/workflow-syntax-for-github-actions

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Events and Triggers

• push: Triggers on git push to branches/tags
• pull_request: Triggers on PR open, sync, reopen
• schedule: Cron syntax for scheduled runs
• workflow_dispatch: Manual trigger from UI
• workflow_call: Make workflow reusable

Path filters: Run only when specific files change

on:
  push:
    paths: ['src/**', '!**/*.md']

Reference: https://docs.github.com/en/actions/using-workflows/events-that-trigger-workflows

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Jobs and Steps

Jobs run in parallel by default. Use needs for sequential execution. Steps run shell commands or reusable actions.

jobs:
  build:
    runs-on: ubuntu-latest
    steps:
      - run: npm run build

  deploy:
    needs: build
    if: github.ref == 'refs/heads/main'
    steps:
      - run: npm run deploy

Reference: https://docs.github.com/en/actions/using-jobs

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Matrix Strategies

Test multiple versions/platforms in parallel.

strategy:
  matrix:
    node: [18, 20, 22]
    os: [ubuntu-latest, windows-latest]
runs-on: ubuntu-latest  # Or use matrix.os variable

Reference: https://docs.github.com/en/actions/using-jobs/using-a-matrix-for-your-jobs

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Caching Dependencies

Cache node_modules, pip packages, or build outputs. Setup actions include built-in caching.

- uses: actions/setup-node@v4
  with:
    cache: npm  # auto-caches node_modules

Manual caching:

- uses: actions/cache@v4
  with:
    path: ~/.npm
    key: OS-node-HASH  # Use: runner.os and hashFiles() variables

Reference: https://docs.github.com/en/actions/using-workflows/caching-dependencies-to-speed-up-workflows

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Secrets Management

Store sensitive data in repository/environment/organization secrets. Automatically masked in logs.

steps:
  - run: echo "API_KEY_VALUE"  # Use secrets.API_KEY variable

OIDC for cloud providers (preferred over static credentials):

Reference: https://docs.github.com/en/actions/security-guides/using-secrets-in-github-actions

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Environment Variables

Define at workflow/job/step level.

env:
  NODE_ENV: production

jobs:
  build:
    env:
      API_URL: https://api.example.com

Reference: https://docs.github.com/en/actions/learn-github-actions/variables

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Reusable Workflows

Share workflows across repositories.

# .github/workflows/reusable.yml
on:
  workflow_call:
    inputs:
      environment:
        required: true
        type: string

# Caller
jobs:
  call:
    uses: ./.github/workflows/reusable.yml
    with:
      environment: production

Reference: https://docs.github.com/en/actions/using-workflows/reusing-workflows

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Templates

Code templates for this domain (in templates/):

• github-workflow.yml — GitHub Actions CI/CD pipeline template

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Resources

• GitHub Actions Docs: https://docs.github.com/en/actions
• Workflow Syntax: https://docs.github.com/en/actions/using-workflows/workflow-syntax-for-github-actions
• Security Best Practices: https://docs.github.com/en/actions/security-guides/security-hardening-for-github-actions
• Caching: https://docs.github.com/en/actions/using-workflows/caching-dependencies-to-speed-up-workflows