docker-compose/CLAUDE.md

# CLAUDE.md

This file provides guidance to Claude Code (claude.ai/code) when working with code in this repository.

## Overview

Multi-service Docker Compose stack named "falcon" managing production services on pivoine.art domain. Uses Arty for configuration management with centralized environment variables and custom scripts.

## Architecture

### Compose Include Pattern
Root `compose.yaml` uses Docker Compose's `include` directive to orchestrate multiple service stacks:
- **core**: Shared PostgreSQL 16 + Redis 7 infrastructure
- **proxy**: Traefik reverse proxy with Let's Encrypt SSL
- **sexy**: Directus 11 CMS + SvelteKit frontend
- **awsm**: Next.js application with SQLite
- **track**: Umami analytics (PostgreSQL)
- **gotify**: Push notification server
- **scrapy**: Scrapyd web scraping cluster (scrapyd, scrapy, scrapyrt)
- **n8n**: Workflow automation platform (PostgreSQL)
- **stash**: Filestash web-based file manager
- **links**: Linkwarden bookmark manager (PostgreSQL + Meilisearch)
- **vault**: Vaultwarden password manager (SQLite)
- **joplin**: Joplin Server note-taking and sync platform (PostgreSQL)
- **kit**: Unified toolkit with Vert file converter and miniPaint image editor (path-routed)
- **jelly**: Jellyfin media server with hardware transcoding
- **drop**: PairDrop peer-to-peer file sharing
- **restic**: Backrest backup system with restic backend
- **sablier**: Dynamic scaling plugin for Traefik
- **vpn**: WireGuard VPN (wg-easy)

All services connect to a single external Docker network (`falcon_network` by default, defined by `$NETWORK_NAME`).

### Environment Management via Arty
Configuration is centralized in `arty.yml`:
- **envs.default**: All environment variables with sensible defaults
- **scripts**: Common Docker Compose and operational commands
- Variables follow naming pattern: `{SERVICE}_COMPOSE_PROJECT_NAME`, `{SERVICE}_TRAEFIK_HOST`, etc.

Sensitive values (passwords, secrets) live in `.env` and override arty.yml defaults.

### Traefik Routing & Security Architecture
Services expose themselves via Docker labels:
- HTTP → HTTPS redirect on `web` entrypoint (port 80)
- SSL termination on `web-secure` entrypoint (port 443)
- Let's Encrypt certificates stored in `proxy` volume
- Path-based routing: `/api` routes to Directus backend, root to frontend
- Compression middleware applied via labels
- All routers scoped to `$NETWORK_NAME` network

**Security Features:**
- **TLS Security**: Minimum TLS 1.2, strong cipher suites (ECDHE, AES-GCM, ChaCha20), SNI strict mode
- **Security Headers**: HSTS (1-year), X-Frame-Options, X-XSS-Protection, Content-Type-Options, Referrer-Policy, Permissions-Policy
- **Dynamic Configuration**: Security settings in `proxy/dynamic/security.yaml` with auto-reload
- **Rate Limiting**: Available middlewares (100 req/s general, 30 req/s API)
- **HTTP Basic Auth**: Scrapyd protected with username/password authentication

### Database Initialization
`core/postgres/init/01-init-databases.sh` runs on first PostgreSQL startup:
- Creates `directus` database for Sexy CMS
- Creates `umami` database for Track analytics
- Creates `n8n` database for workflow automation
- Creates `linkwarden` database for Links bookmark manager
- Creates `joplin` database for Joplin Server
- Grants privileges to `$DB_USER`

## Common Commands

All commands use `pnpm arty` (leveraging scripts in arty.yml):

### Stack Management
```bash
# Start all services
pnpm arty up

# Stop all services
pnpm arty down

# View running containers
pnpm arty ps

# Follow logs for all services
pnpm arty logs

# Restart all services
pnpm arty restart

# Pull latest images
pnpm arty pull

# View rendered configuration (with variables substituted)
pnpm arty config
```

### Network Setup
```bash
# Create external Docker network (required before first up)
pnpm arty net/create
```

### Database Operations (Sexy/Directus)
```bash
# Export Directus database + schema snapshot
pnpm arty db/dump

# Import database dump + apply schema snapshot
pnpm arty db/import

# Export Directus uploads directory
pnpm arty uploads/export

# Import Directus uploads directory
pnpm arty uploads/import
```

### Deployment
```bash
# Sync .env file to remote VPS
pnpm arty env/sync
```

## Service-Specific Details

### Core Services (core/compose.yaml)
- **postgres**: PostgreSQL 16 Alpine, exposed on host port 5432
  - Uses scram-sha-256 authentication
  - Health check via `pg_isready`
  - Init scripts mounted from `./postgres/init/`
- **redis**: Redis 7 Alpine for caching
  - Used by Directus for cache and websocket storage

### Sexy (sexy/compose.yaml)
Directus headless CMS + SvelteKit frontend:
- **directus**: Directus 11.12.0
  - Admin panel + GraphQL/REST API
  - Traefik routes `/api` path to port 8055
  - Volumes: `directus_uploads` for media, `directus_bundle` for extensions
  - Email via SMTP (IONOS configuration in .env)
- **frontend**: Custom SvelteKit app from ghcr.io/valknarxxx/sexy
  - Serves on port 3000
  - Shared `directus_bundle` volume for Directus extensions

### Proxy (proxy/compose.yaml)
Traefik 3.x reverse proxy:
- Global HTTP→HTTPS redirect
- Let's Encrypt via TLS challenge
- Dashboard disabled (`api.dashboard=false`)
- Reads labels from Docker socket (`/var/run/docker.sock`)
- Scoped to `$NETWORK_NAME` network via provider configuration

### AWSM (awsm/compose.yaml)
Next.js app with embedded SQLite:
- Serves awesome-app list directory
- Optional GitHub token for API rate limits
- Optional webhook secret for database updates
- Database persisted in `awesome_data` volume

### Scrapy (scrapy/compose.yaml)
Web scraping cluster with three services:
- **scrapyd**: Scrapyd daemon exposed at `scrapy.pivoine.art:6800`
  - Web interface for deploying and managing spiders
  - Protected by HTTP Basic Auth (credentials in `.env`)
  - Data persisted in `scrapyd_data` volume
- **scrapy**: Development container for running Scrapy commands
  - Shared `scrapy_code` volume for spider projects
- **scrapyrt**: Scrapyd Real-Time API on port 9080
  - Run spiders via HTTP API without scheduling

**Authentication**: Access requires username/password (stored as `SCRAPY_AUTH_USERS` in `.env` using htpasswd format)

### n8n (n8n/compose.yaml)
Workflow automation platform:
- **n8n**: n8n application exposed at `n8n.pivoine.art:5678`
  - Visual workflow builder with 200+ integrations
  - PostgreSQL backend for workflow persistence
  - Runners enabled for task execution
  - Webhook support for external triggers
  - Data persisted in `n8n_data` volume

### Stash (stash/compose.yaml)
Web-based file manager:
- **filestash**: Filestash app exposed at `stash.pivoine.art:8334`
  - Support for multiple storage backends (SFTP, S3, Dropbox, Google Drive, FTP, WebDAV)
  - In-browser file viewer and media player
  - File sharing capabilities
  - Data persisted in `filestash_data` volume

### Links (links/compose.yaml)
Linkwarden bookmark manager with full-text search:
- **linkwarden**: Linkwarden app exposed at `links.pivoine.art:3000`
  - Bookmark and link management with collections
  - Full-text search via Meilisearch
  - Collaborative bookmark sharing
  - Screenshot and PDF archiving
  - Browser extension support
  - PostgreSQL backend for bookmark persistence
  - Data persisted in `linkwarden_data` volume
- **linkwarden_meilisearch**: Meilisearch v1.12.8 search engine
  - Powers full-text search for bookmarks
  - Data persisted in `linkwarden_meili_data` volume

**Required Environment Variables** (add to `.env`):
- `LINKS_NEXTAUTH_SECRET`: NextAuth.js secret for session encryption
- `LINKS_MEILI_MASTER_KEY`: Meilisearch master key for API authentication

### Vault (vault/compose.yaml)
Vaultwarden password manager (Bitwarden-compatible server):
- **vaultwarden**: Vaultwarden app exposed at `vault.pivoine.art:80`
  - Self-hosted password manager compatible with Bitwarden clients
  - Supports TOTP, WebAuthn/U2F two-factor authentication
  - Secure password generation and sharing
  - Browser extensions and mobile apps available
  - Emergency access and organization support
  - Data persisted in `vaultwarden_data` volume (SQLite database)

**Configuration**:
- **DOMAIN**: `https://vault.pivoine.art` (required for proper HTTPS operation)
- **WEBSOCKET_ENABLED**: `true` (enables real-time sync)
- **SIGNUPS_ALLOWED**: `false` (disable open registrations for security)
- **INVITATIONS_ALLOWED**: `true` (allow inviting users)
- **SHOW_PASSWORD_HINT**: `false` (security best practice)

**Important**:
- First user to register becomes the admin
- Use strong master password - it cannot be recovered
- Enable 2FA for all accounts
- Access admin panel at `/admin` (requires `ADMIN_TOKEN` in `.env`)

### Joplin (joplin/compose.yaml)
Joplin Server note-taking and synchronization platform:
- **joplin**: Joplin Server app exposed at `joplin.pivoine.art:22300`
  - Self-hosted sync server for Joplin note-taking clients
  - End-to-end encryption support for notebooks
  - Multi-device synchronization (desktop, mobile, CLI)
  - Markdown-based notes with attachments
  - PostgreSQL backend for data persistence
  - Compatible with official Joplin clients (Windows, macOS, Linux, Android, iOS)
  - Data persisted in PostgreSQL `joplin` database

**Configuration**:
- **APP_BASE_URL**: `https://joplin.pivoine.art` (required for client synchronization)
- **APP_PORT**: `22300` (Joplin Server default port)
- **DB_CLIENT**: `pg` (PostgreSQL database driver)
- Uses shared core PostgreSQL instance

**Usage**:
1. Access https://joplin.pivoine.art to create an account
2. In Joplin desktop/mobile app, go to Settings → Synchronization
3. Select "Joplin Server" as sync target
4. Enter server URL: `https://joplin.pivoine.art`
5. Enter email and password created in step 1

### Kit (kit/compose.yaml)
Unified toolkit with landing page, file conversion, image editing, and color palette generation using subdomain routing:
- **Landing**: `kit.pivoine.art` - Toolkit landing page
- **Vert**: `vert.kit.pivoine.art` - Universal file format converter
- **Paint**: `paint.kit.pivoine.art` - Web-based image editor
- **Pastel**: `pastel.kit.pivoine.art` - Color palette generator (API + UI)

#### Landing Page (kit.pivoine.art)
Kit toolkit landing page:
- Main entry point for the toolkit
- Links to Vert and Paint services
- Clean, simple interface

#### Vert Service (vert.kit.pivoine.art)
VERT universal file format converter:
- WebAssembly-based file conversion (client-side processing)
- Supports 250+ file formats (images, audio, documents, video)
- No file size limits
- Privacy-focused: all conversions happen in the browser
- No persistent data storage required
- Publicly accessible (no authentication required)

**Configuration**:
- **PUB_HOSTNAME**: `vert.kit.pivoine.art` (public hostname)
- **PUB_ENV**: `production` (environment mode)
- **PUB_DISABLE_ALL_EXTERNAL_REQUESTS**: `true` (privacy mode)

**Usage**:
Access https://vert.kit.pivoine.art and drag/drop files to convert between formats. All processing happens in your browser using WebAssembly - no data is uploaded to the server.

#### Paint Service (paint.kit.pivoine.art)
miniPaint web-based image editor built from GitHub:
- Online image editor with layer support
- Built directly from https://github.com/viliusle/miniPaint
- Supports PNG, JPG, GIF, WebP formats
- Features: layers, filters, drawing tools, text, shapes
- Client-side processing (no uploads to server)
- No persistent data storage required
- Stateless architecture

**Build Process**:
- Multi-stage Docker build clones from GitHub
- Builds using Node.js 18
- Serves static files via nginx

**Usage**:
Access https://paint.kit.pivoine.art to use the image editor. All editing happens in the browser - images are not uploaded to the server.

#### Pastel Service (pastel.kit.pivoine.art)
Pastel color palette generator with API and UI:
- Generate beautiful color palettes
- API endpoint at `/api` for programmatic access
- Web UI for interactive palette generation
- Color harmony algorithms
- Export palettes in various formats
- Stateless architecture

**Architecture**:
- **API**: Backend service handling color generation logic
- **UI**: Frontend application consuming the API

**Images**:
- API: `ghcr.io/valknarness/pastel-api:latest`
- UI: `ghcr.io/valknarness/pastel-ui:latest`

**Routing**:
- UI: `https://pastel.kit.pivoine.art` (root path)
- API: `https://pastel.kit.pivoine.art/api` (path prefix)

**Usage**:
Access https://pastel.kit.pivoine.art to generate and explore color palettes interactively.

**Note**: Kit services (Vert, Paint, Pastel) are stateless and don't require backups as no data is persisted.

### PairDrop (drop/compose.yaml)
PairDrop peer-to-peer file sharing service:
- **pairdrop**: PairDrop app (linuxserver/pairdrop image) exposed at `drop.pivoine.art:3000`
  - Browser-based peer-to-peer file sharing
  - WebRTC-based direct device-to-device transfers
  - No server-side storage - files transfer directly between devices
  - Works across different networks using STUN servers
  - No account required - devices are discovered automatically
  - Supports sharing files, text, and clipboard content
  - Mobile and desktop browser support

**Configuration**:
- **RTC_CONFIG**: WebRTC configuration file at `/rtc_config.json`
  - Configures STUN servers for NAT traversal
  - Uses Google's public STUN servers for cross-network connectivity
  - Enables peer connections between devices on different networks (WiFi to cellular, etc.)
- **RATE_LIMIT**: `true` (prevents abuse)
- **WS_FALLBACK**: `false` (disables WebSocket fallback)

**Usage**:
1. Access https://drop.pivoine.art on both devices
2. Devices will automatically discover each other if on the same network
3. For different networks, STUN servers enable peer discovery
4. Click on discovered device to share files or text

**Technical Details**:
- Uses WebRTC for direct peer-to-peer connections
- STUN servers help with NAT traversal and cross-network connections
- Configuration file mounted at `/rtc_config.json` with Google STUN servers
- No data persisted - stateless service

**Note**: PairDrop doesn't require backups as no data is stored on the server.

### Jellyfin (jelly/compose.yaml)
Jellyfin media server for streaming photos and videos:
- **jellyfin**: Jellyfin app exposed at `jelly.pivoine.art:8096`
  - Self-hosted media streaming server
  - Hardware transcoding support for video playback
  - Automatic media library organization with metadata
  - Multi-device support (web, mobile apps, TV apps)
  - User management with watch history and favorites
  - Subtitle support and on-the-fly transcoding
  - Data persisted in `jellyfin_config` and `jellyfin_cache` volumes

**Media Sources**:
- **Pictures**: `/mnt/hidrive/users/valknar/Pictures` (read-only)
- **Videos**: `/mnt/hidrive/users/valknar/Videos` (read-only)
- Uses HiDrive WebDAV mount via davfs2 on host

**Configuration**:
- First access: Create admin account at https://jelly.pivoine.art
- Add media libraries pointing to `/media/pictures` and `/media/videos`
- Configure transcoding settings in Dashboard → Playback
- Enable hardware acceleration if available

**Usage**:
Access https://jelly.pivoine.art to browse and stream your media. Jellyfin will automatically organize your content, fetch metadata, and provide optimized streaming to any device.

**Note**: Jellyfin requires the HiDrive WebDAV mount to be active on the host at `/mnt/hidrive`.

### PairDrop (drop/compose.yaml)
PairDrop peer-to-peer file sharing service:
- **pairdrop**: PairDrop app exposed at `drop.pivoine.art:3000`
  - Local network file sharing between devices
  - Peer-to-peer file transfer via WebRTC
  - No file size limits
  - Works across platforms (desktop, mobile, tablets)
  - End-to-end encrypted transfers
  - No file uploads to server (direct peer connections)
  - Rate limiting enabled for security
  - Stateless architecture (no data persistence)

**Features**:
- Share files by opening the same URL on multiple devices
- Devices on the same network automatically discover each other
- Works across different networks via public room codes
- Text messages and file sharing support
- Progressive Web App (PWA) installable on mobile

**Usage**:
1. Open https://drop.pivoine.art on your device
2. Open the same URL on another device
3. Devices will appear and you can share files directly
4. Files transfer peer-to-peer without uploading to server

**Note**: PairDrop is stateless and doesn't require backups as no data is persisted. All transfers happen directly between devices.

### Restic (restic/compose.yaml)
Backrest backup system with restic backend:
- **backrest**: Backrest web UI exposed at `restic.pivoine.art:9898`
  - Web-based interface for managing restic backups
  - Automated scheduled backups with retention policies
  - Support for multiple backup plans and repositories
  - Real-time backup status and history
  - Restore capabilities via web UI
  - Data persisted in `backrest_data`, `backrest_config`, `backrest_cache` volumes

**Repository Configuration**:
- **Name**: `hidrive-backup`
- **URI**: `/repos` (mounted from `/mnt/hidrive/users/valknar/Backup`)
- **Password**: `falcon-backup-2025`
- **Auto-initialize**: Enabled (creates repository if missing)
- **Auto-unlock**: Enabled (automatically unlocks stuck repositories)
- **Maintenance**:
  - Prune: Weekly (Sundays at 2 AM) - removes old snapshots per retention policy
  - Check: Weekly (Sundays at 3 AM) - verifies repository integrity

**Backup Plans** (11 automated daily backups):
1. **postgres-backup** (2 AM daily)
   - Path: `/volumes/core_postgres_data`
   - Retention: 7 daily, 4 weekly, 6 monthly, 2 yearly

2. **redis-backup** (3 AM daily)
   - Path: `/volumes/core_redis_data`
   - Retention: 7 daily, 4 weekly, 3 monthly

3. **directus-uploads-backup** (4 AM daily)
   - Path: `/volumes/directus_uploads`
   - Retention: 7 daily, 4 weekly, 6 monthly, 2 yearly

4. **directus-bundle-backup** (4 AM daily)
   - Path: `/volumes/directus_bundle`
   - Retention: 7 daily, 4 weekly, 3 monthly

5. **awesome-backup** (5 AM daily)
   - Path: `/volumes/awesome_data`
   - Retention: 7 daily, 4 weekly, 6 monthly

6. **gotify-backup** (5 AM daily)
   - Path: `/volumes/gotify_data`
   - Retention: 7 daily, 4 weekly, 3 monthly

7. **scrapy-backup** (6 AM daily)
   - Paths: `/volumes/scrapyd_data`, `/volumes/scrapy_code`
   - Retention: 7 daily, 4 weekly, 3 monthly

8. **n8n-backup** (6 AM daily)
   - Path: `/volumes/n8n_data`
   - Retention: 7 daily, 4 weekly, 6 monthly

9. **filestash-backup** (7 AM daily)
   - Path: `/volumes/filestash_data`
   - Retention: 7 daily, 4 weekly, 3 monthly

10. **linkwarden-backup** (7 AM daily)
    - Paths: `/volumes/linkwarden_data`, `/volumes/linkwarden_meili_data`
    - Retention: 7 daily, 4 weekly, 6 monthly

11. **letsencrypt-backup** (8 AM daily)
    - Path: `/volumes/letsencrypt_data`
    - Retention: 7 daily, 4 weekly, 12 monthly, 3 yearly

12. **vaultwarden-backup** (8 AM daily)
    - Path: `/volumes/vaultwarden_data`
    - Retention: 7 daily, 4 weekly, 12 monthly, 3 yearly

13. **joplin-backup** (2 AM daily)
    - Path: `/volumes/joplin_data`
    - Retention: 7 daily, 4 weekly, 6 monthly, 2 yearly

14. **jellyfin-backup** (9 AM daily)
    - Path: `/volumes/jelly_config`
    - Retention: 7 daily, 4 weekly, 6 monthly, 2 yearly

**Volume Mounting**:
All Docker volumes are mounted read-only to `/volumes/` with prefixed names (e.g., `backup_core_postgres_data`) to avoid naming conflicts with other compose stacks.

**Configuration Management**:
- `config.json` template in repository defines all backup plans
- On first run, copy config into volume: `docker cp restic/config.json restic_app:/config/config.json`
- Config version must be `4` for Backrest 1.10.1 compatibility
- Backrest manages auth automatically (username: `valknar`, password set via web UI on first access)

**Important**: The backup destination path `/mnt/hidrive/users/valknar/Backup` must be accessible from the container. Ensure HiDrive is mounted on the host before starting the backup service.

## Important Environment Variables

Key variables defined in `arty.yml` and overridden in `.env`:
- `NETWORK_NAME`: Docker network name (default: `falcon_network`)
- `ADMIN_EMAIL`: Used for Let's Encrypt and service admin accounts
- `DB_USER`, `DB_PASSWORD`: PostgreSQL credentials
- `CORE_DB_HOST`, `CORE_DB_PORT`: PostgreSQL connection (default: `postgres:5432`)
- `CORE_REDIS_HOST`, `CORE_REDIS_PORT`: Redis connection (default: `redis:6379`)
- `{SERVICE}_TRAEFIK_HOST`: Domain for each service
- `{SERVICE}_TRAEFIK_ENABLED`: Toggle Traefik exposure
- `SEXY_DIRECTUS_SECRET`: Directus security secret
- `TRACK_APP_SECRET`: Umami analytics secret

## Volume Management

Each service uses named volumes prefixed with project name:
- `core_postgres_data`, `core_redis_data`: Database persistence
- `core_directus_uploads`, `core_directus_bundle`: Directus media/extensions
- `awesome_data`: AWSM SQLite database
- `scrapy_scrapyd_data`, `scrapy_scrapy_code`: Scrapy spider data and code
- `n8n_n8n_data`: n8n workflow data
- `stash_filestash_data`: Filestash configuration and state
- `links_data`, `links_meili_data`: Linkwarden bookmarks and Meilisearch index
- `vault_data`: Vaultwarden password vault (SQLite database)
- `restic_data`, `restic_config`, `restic_cache`, `restic_tmp`: Backrest backup system
- `proxy_letsencrypt_data`: SSL certificates

Volumes can be inspected with:
```bash
docker volume ls | grep falcon
docker volume inspect <volume_name>
```

## Security Configuration

### HTTP Basic Authentication
Protected services (Scrapy, VERT, Proxy dashboard) use HTTP Basic Auth via Traefik middleware:
- **Shared credentials** stored in `.env` as `AUTH_USERS`
- Format: `username:$apr1$hash` (Apache htpasswd format)
- Generate new hash: `openssl passwd -apr1 'your_password'`
- Remember to escape `$` signs with `$$` in `.env` files

**Protected Services:**
- Scrapy (scrapyd + UI)
- VERT (file converter)
- Traefik Proxy dashboard

**To update credentials:**
```bash
# Generate hash
echo "username:$(openssl passwd -apr1 'new_password')"

# Update .env with shared credentials
AUTH_USERS=username:$$apr1$$hash$$here

# Sync to VPS
rsync -avzhe ssh .env root@vps:~/Projects/docker-compose/

# Restart services
ssh -A root@vps "cd ~/Projects/docker-compose && arty restart"
```

### Security Headers & TLS
Global security settings applied via `proxy/dynamic/security.yaml`:
- **TLS**: Minimum TLS 1.2, strong ciphers only, SNI strict mode
- **Headers**: HSTS, X-Frame-Options, CSP, Referrer-Policy, etc.
- **Rate Limiting**: Available middlewares for DDoS protection

Test security:
```bash
# Check headers
curl -I https://scrapy.pivoine.art

# SSL Labs test
# Visit: https://www.ssllabs.com/ssltest/analyze.html?d=scrapy.pivoine.art
```

### Modifying Security Settings
Edit `proxy/dynamic/security.yaml` to customize:
- TLS versions and cipher suites
- Security header values
- Rate limiting thresholds

Traefik automatically reloads changes (no restart needed).

## Troubleshooting

### Services won't start
1. Ensure external network exists: `pnpm arty net/create`
2. Check if services reference correct `$NETWORK_NAME` in labels
3. Verify `.env` has required secrets (compare with `arty.yml` envs.default)

### SSL certificates failing
1. Check `ADMIN_EMAIL` is set in `.env`
2. Ensure ports 80/443 are accessible from internet
3. Inspect Traefik logs: `docker logs proxy_app`

### Database connection errors
1. Check PostgreSQL is healthy: `docker ps` (should show healthy status)
2. Verify database exists: `docker exec core_postgres psql -U $DB_USER -l`
3. Check credentials match between `.env` and service configs

### Directus schema migration
- Export schema: `pnpm arty db/dump` (creates `sexy/directus.yaml`)
- Import to new instance: `pnpm arty db/import` (applies schema snapshot)
- Schema file stored in `sexy/directus.yaml` for version control