# Docker Git Deployment Strategy - Quick Guide

A proven deployment strategy for Next.js apps (or any Node.js app) on a VPS using Docker with Git integration.

## Quick Overview

**Strategy**: Docker containers + Git repo integration + Zero-downtime deployments  
**Benefits**: Reproducible builds, easy rollbacks, consistent environments  
**Time to setup**: ~30 minutes

---

## Step 1: Create Docker Files

### `Dockerfile` (Production)
```dockerfile
FROM node:22.11.0

# Set timezone (adjust for your region)
ENV TZ=Europe/Warsaw
RUN ln -snf /usr/share/zoneinfo/$TZ /etc/localtime && echo $TZ > /etc/timezone

# Install git for repo cloning
RUN apt-get update && apt-get install -y git && rm -rf /var/lib/apt/lists/*

WORKDIR /app

# Support building from Git repo
ARG GIT_REPO_URL
ARG GIT_BRANCH=main
ARG GIT_COMMIT

# Clone from git OR use local files
RUN if [ -n "$GIT_REPO_URL" ]; then \
    git clone --branch ${GIT_BRANCH} ${GIT_REPO_URL} . && \
    if [ -n "$GIT_COMMIT" ]; then git checkout ${GIT_COMMIT}; fi; \
  fi

COPY package*.json ./
RUN npm install

COPY . .
RUN npm run build

# Copy entrypoint script
COPY docker-entrypoint.sh /docker-entrypoint.sh
RUN chmod +x /docker-entrypoint.sh

EXPOSE 3000
ENTRYPOINT ["/docker-entrypoint.sh"]
```

### `docker-entrypoint.sh`
```bash
#!/bin/bash
echo "🚀 Starting application..."

# Create necessary directories
mkdir -p /app/data
mkdir -p /app/public/uploads

# Initialize database, create admin, etc.
node scripts/init-setup.js

# Start the app
exec npm start
```

### `docker-compose.prod.yml`
```yaml
version: "3.9"

services:
  app:
    build:
      context: .
      dockerfile: Dockerfile
      args:
        - GIT_REPO_URL=${GIT_REPO_URL}
        - GIT_BRANCH=${GIT_BRANCH:-main}
        - GIT_COMMIT=${GIT_COMMIT}
    ports:
      - "3001:3000"  # HOST:CONTAINER
    volumes:
      - ./data:/app/data              # Persist database
      - ./uploads:/app/public/uploads # Persist files
    environment:
      - NODE_ENV=production
      - TZ=Europe/Warsaw
      - NEXTAUTH_SECRET=${NEXTAUTH_SECRET}
      - NEXTAUTH_URL=${NEXTAUTH_URL}
      - AUTH_TRUST_HOST=true
    restart: unless-stopped
```

---

## Step 2: Create Deployment Script

### `deploy.sh` (Linux/Mac)
```bash
#!/bin/bash
set -e

GIT_REPO_URL=${1:-""}
GIT_BRANCH=${2:-"main"}
GIT_COMMIT=${3:-""}

# Load environment variables
if [ -f .env.production ]; then
    export $(grep -v '^#' .env.production | xargs)
fi

# Validate critical vars
if [ -z "$NEXTAUTH_SECRET" ] || [ -z "$NEXTAUTH_URL" ]; then
    echo "ERROR: Set NEXTAUTH_SECRET and NEXTAUTH_URL in .env.production"
    exit 1
fi

# Build from Git or local files
if [ -z "$GIT_REPO_URL" ]; then
    echo "Building from local files..."
    docker-compose -f docker-compose.prod.yml build
else
    echo "Building from git: $GIT_REPO_URL (branch: $GIT_BRANCH)"
    GIT_REPO_URL=$GIT_REPO_URL GIT_BRANCH=$GIT_BRANCH GIT_COMMIT=$GIT_COMMIT \
    docker-compose -f docker-compose.prod.yml build
fi

# Deploy
echo "Deploying..."
docker-compose -f docker-compose.prod.yml down
docker-compose -f docker-compose.prod.yml up -d

echo "✅ Deployment completed!"
echo "Application running at: $NEXTAUTH_URL (port 3001 on host)"
```

Make it executable:
```bash
chmod +x deploy.sh
```

---

## Step 3: Configure Environment

### `.env.production`
```bash
# Generate secret: openssl rand -base64 32
NEXTAUTH_SECRET=your-super-long-random-secret-at-least-32-chars

# Your public URL
NEXTAUTH_URL=https://yourdomain.com

NODE_ENV=production
AUTH_TRUST_HOST=true
```

**⚠️ NEVER commit `.env.production` to Git!**

---

## Step 4: Setup VPS

### Initial VPS Setup
```bash
# SSH to VPS
ssh user@your-vps-ip

# Install Docker & Docker Compose
curl -fsSL https://get.docker.com -o get-docker.sh
sudo sh get-docker.sh
sudo usermod -aG docker $USER
sudo apt install docker-compose-plugin

# Logout and login again for docker group to take effect
exit
```

### Setup Project Directory
```bash
ssh user@your-vps-ip

# Create project directory
mkdir -p ~/app
cd ~/app

# Copy deployment files (from local machine):
# scp docker-compose.prod.yml deploy.sh user@vps-ip:~/app/
# scp .env.production user@vps-ip:~/app/

# OR clone entire repo if using local file deployment:
git clone https://your-repo-url.git .
```

---

## Step 5: Setup Nginx Reverse Proxy

### Install Nginx
```bash
sudo apt update
sudo apt install nginx certbot python3-certbot-nginx
```

### Configure Nginx
Create `/etc/nginx/sites-available/yourapp`:
```nginx
server {
    listen 80;
    server_name yourdomain.com;

    location / {
        proxy_pass http://localhost:3001;
        proxy_http_version 1.1;
        proxy_set_header Upgrade $http_upgrade;
        proxy_set_header Connection 'upgrade';
        proxy_set_header Host $host;
        proxy_cache_bypass $http_upgrade;
        proxy_set_header X-Real-IP $remote_addr;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_set_header X-Forwarded-Proto $scheme;
    }
}
```

Enable site:
```bash
sudo ln -s /etc/nginx/sites-available/yourapp /etc/nginx/sites-enabled/
sudo nginx -t
sudo systemctl restart nginx
```

### Setup SSL (HTTPS)
```bash
sudo certbot --nginx -d yourdomain.com
# Follow prompts to get free SSL certificate
```

---

## Step 6: Deploy!

### Deployment Methods

**Method 1: From Local Files**
```bash
cd ~/app
git pull origin main  # Update code
./deploy.sh
```

**Method 2: From Git Repository**
```bash
cd ~/app
./deploy.sh https://git.yourserver.com/user/repo.git main
```

**Method 3: Specific Commit**
```bash
./deploy.sh https://git.yourserver.com/user/repo.git main abc123def
```

---

## Ongoing Maintenance

### View Logs
```bash
docker-compose -f docker-compose.prod.yml logs -f
```

### Restart App
```bash
docker-compose -f docker-compose.prod.yml restart
```

### Full Rebuild (for Dockerfile changes)
```bash
docker-compose -f docker-compose.prod.yml down
docker-compose -f docker-compose.prod.yml build --no-cache
docker-compose -f docker-compose.prod.yml up -d
```

### Check Container Status
```bash
docker-compose -f docker-compose.prod.yml ps
docker-compose -f docker-compose.prod.yml exec app date  # Check timezone
```

### Backup Data
```bash
# Automated daily database backups are scheduled at 2 AM
# Backups are stored in ./backups/ directory, keeping last 30
# Check backup logs: docker-compose -f docker-compose.prod.yml exec app cat /app/data/backup.log

# Manual backup (if needed)
tar -czf backup-$(date +%Y%m%d).tar.gz data/ uploads/

# Download backups to local machine
scp user@vps-ip:~/app/backups/backup-*.sqlite ./local-backups/
```

### Rollback to Previous Version
```bash
# If using Git commits
./deploy.sh https://git.yourserver.com/user/repo.git main PREVIOUS_COMMIT_HASH
```

---

## Troubleshooting

### Container won't start
```bash
docker-compose -f docker-compose.prod.yml logs app
docker-compose -f docker-compose.prod.yml exec app sh  # Get shell inside container
```

### Timezone issues
- Make sure `TZ` env var is set in docker-compose
- Rebuild image: timezone config is baked in during build
- Verify: `docker-compose -f docker-compose.prod.yml exec app date`

### Permission issues with volumes
```bash
# Fix ownership
sudo chown -R $USER:$USER data/ uploads/
```

### Port already in use
```bash
# Check what's using port 3001
sudo netstat -tulpn | grep 3001
# Change port in docker-compose.prod.yml if needed
```

---

## Security Checklist

- [ ] Strong `NEXTAUTH_SECRET` generated (min 32 chars)
- [ ] `.env.production` has secure permissions: `chmod 600 .env.production`
- [ ] Firewall configured: `sudo ufw allow 80,443/tcp`
- [ ] SSL certificate installed via Certbot
- [ ] Regular security updates: `sudo apt update && sudo apt upgrade`
- [ ] Docker images updated periodically
- [ ] Database backups automated
- [ ] Git credentials NOT stored in environment files

---

## Quick Reference

```bash
# Deploy from Git
./deploy.sh https://git.server.com/user/repo.git main

# Deploy from local files
git pull && ./deploy.sh

# View logs
docker-compose -f docker-compose.prod.yml logs -f

# Restart
docker-compose -f docker-compose.prod.yml restart

# Rebuild completely
docker-compose -f docker-compose.prod.yml down
docker-compose -f docker-compose.prod.yml build --no-cache
docker-compose -f docker-compose.prod.yml up -d

# Backup
tar -czf backup-$(date +%Y%m%d).tar.gz data/ uploads/
```

---

## Key Advantages of This Strategy

✅ **Git Integration**: Deploy specific commits, branches, or tags  
✅ **Reproducible**: Same build every time  
✅ **Easy Rollbacks**: Just deploy previous commit  
✅ **Isolated**: Container doesn't pollute host system  
✅ **Persistent Data**: Volumes survive container rebuilds  
✅ **Zero-Config Deployment**: Clone and run `./deploy.sh`  
✅ **Works Offline**: Can build from local files without Git  
✅ **Auto-Restart**: Container restarts on crash or reboot  

---

## Notes to Future Self

1. **Always use volumes** for data persistence (database, uploads)
2. **Timezone matters**: Set it in both Dockerfile and docker-compose
3. **Rebuild vs Restart**: Dockerfile changes need rebuild, code changes just restart
4. **Port mapping**: Be consistent (I use 3001:3000 - HOST:CONTAINER)
5. **Environment secrets**: Never commit, always use `.env.production`
6. **Nginx**: Don't forget to setup reverse proxy and SSL
7. **Git auth**: For private repos, use SSH keys or tokens in URL
8. **Test locally first**: Use `docker-compose.yml` with `Dockerfile.dev`
9. **Monitor logs**: Set up log rotation if app is chatty
10. **Automate backups**: Cron job for daily database/file backups

---

**Time to deploy a new app with this strategy: ~20 minutes** ⚡

Copy these files, adjust for your app (mainly environment variables and init scripts), and you're production-ready!