# Referensi Cepat GitHub Actions

*Workflow, trigger, job, secret, caching, artifact*

> Source: GitHub Actions Documentation (docs.github.com/actions) · MIT

## Dasar Workflow

### Workflow Minimal

```
# .github/workflows/ci.yml
name: CI
on: push
jobs:
  build:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
      - run: echo "Hello from CI"
```

### Konsep Utama

| Command | Description |
|---------|-------------|
| `Workflow` | File YAML di `.github/workflows/` yang mendefinisikan otomasi |
| `Event` | Trigger yang memulai workflow (push, PR, jadwal, dll.) |
| `Job` | Kumpulan step yang berjalan di runner yang sama |
| `Step` | Tugas individual — menjalankan perintah atau menggunakan action |
| `Runner` | VM yang menjalankan job (`ubuntu-latest`, `macos-latest`, `windows-latest`) |
| `Action` | Unit kode yang bisa digunakan ulang, direferensikan dengan `uses:` |

## Trigger

### Event Umum

```
on:
  push:
    branches: [main]
  pull_request:
    branches: [main]
  schedule:
    - cron: "0 6 * * 1"    # every Monday 6 AM UTC
  workflow_dispatch:          # manual trigger
```

### Filter Event

| Command | Description |
|---------|-------------|
| `branches:` | Trigger hanya untuk branch tertentu |
| `paths:` | Trigger hanya saat file yang cocok berubah |
| `tags:` | Trigger saat push tag (`v*`) |
| `types: [opened, synchronize]` | Filter tipe aktivitas PR |
| `branches-ignore:` | Kecualikan branch tertentu |
| `paths-ignore:` | Kecualikan path file tertentu |

## Job & Step

### Konfigurasi Job

```
jobs:
  test:
    runs-on: ubuntu-latest
    needs: build            # depends on build job
    if: github.ref == 'refs/heads/main'
    timeout-minutes: 10
    steps:
      - uses: actions/checkout@v4
      - run: npm test
```

### Tipe Step

| Command | Description |
|---------|-------------|
| `run:` | Jalankan perintah shell |
| `uses:` | Gunakan action yang sudah dipublikasikan |
| `with:` | Teruskan input ke action |
| `name:` | Nama tampilan di UI |
| `id:` | Referensikan output step via `steps.<id>.outputs` |
| `if:` | Eksekusi kondisional |
| `continue-on-error: true` | Jangan gagalkan job jika step gagal |

## Action

### Menggunakan Action

```
steps:
  - uses: actions/checkout@v4
  - uses: actions/setup-node@v4
    with:
      node-version: 20
  - uses: ./.github/actions/my-action  # local action
```

### Action Populer

| Command | Description |
|---------|-------------|
| `actions/checkout@v4` | Checkout kode repository |
| `actions/setup-node@v4` | Install Node.js |
| `actions/setup-python@v5` | Install Python |
| `actions/upload-artifact@v4` | Upload artifact build |
| `actions/download-artifact@v4` | Unduh artifact dari job lain |
| `actions/cache@v4` | Cache dependensi antar run |
| `actions/github-script@v7` | Jalankan JS dengan klien GitHub API |

## Environment Variable

### Mengatur Variabel

```
env:                          # workflow-level
  NODE_ENV: production
jobs:
  build:
    env:                      # job-level
      CI: true
    steps:
      - run: echo "$MY_VAR"
        env:                  # step-level
          MY_VAR: hello
```

### Variabel Default

| Command | Description |
|---------|-------------|
| `github.sha` | SHA commit yang memicu workflow |
| `github.ref` | Ref branch atau tag (`refs/heads/main`) |
| `github.repository` | Nama owner/repo |
| `github.actor` | User yang memicu workflow |
| `github.event_name` | Event yang memicu workflow |
| `runner.os` | OS runner (`Linux`, `macOS`, `Windows`) |

## Secret

### Menggunakan Secret

```
steps:
  - run: deploy --token "$TOKEN"
    env:
      TOKEN: ${{ secrets.DEPLOY_TOKEN }}
  - uses: some/action@v1
    with:
      api-key: ${{ secrets.API_KEY }}
```

### Aturan Secret

| Command | Description |
|---------|-------------|
| `secrets.GITHUB_TOKEN` | Token yang dibuat otomatis, dicakup ke repo |
| `Settings → Secrets` | Tambah secret di pengaturan repo atau org |
| `Masking` | Nilai secret disembunyikan di log secara otomatis |
| `Environment secrets` | Dicakup ke environment deployment |
| `Org secrets` | Dibagikan ke seluruh repo dalam organisasi |

## Matrix Strategy

### Matrix Build

```
jobs:
  test:
    strategy:
      matrix:
        os: [ubuntu-latest, macos-latest]
        node: [18, 20]
    runs-on: ${{ matrix.os }}
    steps:
      - uses: actions/setup-node@v4
        with:
          node-version: ${{ matrix.node }}
```

### Opsi Matrix

| Command | Description |
|---------|-------------|
| `matrix:` | Definisikan kombinasi variabel yang akan di-expand |
| `include:` | Tambah kombinasi tambahan ke matrix |
| `exclude:` | Hapus kombinasi tertentu |
| `fail-fast: false` | Lanjutkan job lain jika satu gagal |
| `max-parallel: 2` | Batasi job matrix yang berjalan bersamaan |

## Caching

### Cache Dependensi

```
- uses: actions/cache@v4
  with:
    path: ~/.npm
    key: npm-${{ hashFiles('package-lock.json') }}
    restore-keys: npm-
```

### Caching Bawaan

```
- uses: actions/setup-node@v4
  with:
    node-version: 20
    cache: npm            # auto-cache for npm/yarn/pnpm
- uses: actions/setup-python@v5
  with:
    python-version: "3.12"
    cache: pip            # auto-cache for pip
```

## Artifact

### Upload & Download

```
- uses: actions/upload-artifact@v4
  with:
    name: build-output
    path: dist/
    retention-days: 7
- uses: actions/download-artifact@v4
  with:
    name: build-output
```

### Catatan Artifact

| Command | Description |
|---------|-------------|
| `retention-days` | Hapus otomatis setelah N hari (default 90) |
| `path` | File atau direktori yang diunggah (mendukung glob) |
| `Lintas-job` | Upload di satu job, download di job lain dengan `needs:` |
| `compression-level` | 0 (tidak ada) hingga 9 (maksimal), default 6 |

## Pola Umum

### Deployment Kondisional

```
- name: Deploy to production
  if: github.ref == 'refs/heads/main'
  run: ./deploy.sh
- name: Post PR comment
  if: github.event_name == 'pull_request'
  run: gh pr comment $PR --body "Build passed"
```

### Ekspresi Berguna

| Command | Description |
|---------|-------------|
| `success()` | True jika semua step sebelumnya berhasil |
| `failure()` | True jika ada step sebelumnya yang gagal |
| `always()` | Jalankan terlepas dari status (cleanup) |
| `cancelled()` | True jika workflow dibatalkan |
| `contains(github.ref, 'release')` | Pemeriksaan contains string |
| `startsWith(github.ref, 'refs/tags')` | Pemeriksaan prefix string |
| `hashFiles('**/lock*')` | SHA-256 file (untuk cache key) |