# Deployment Guide

This guide covers deploying the Hasher application to production.

## Prerequisites

- Node.js 18.x or higher
- Elasticsearch 8.x cluster
- Domain name (optional, for custom domain)
- SSL certificate (recommended for production)

## Deployment Options

### Option 1: Vercel (Recommended for Next.js)

Vercel provides seamless deployment for Next.js applications.

#### Steps:

1. **Install Vercel CLI**:
   ```bash
   npm install -g vercel
   ```

2. **Login to Vercel**:
   ```bash
   vercel login
   ```

3. **Deploy**:
   ```bash
   vercel
   ```

4. **Set Environment Variables**:
   - Go to your project settings on Vercel
   - Add environment variable: `ELASTICSEARCH_NODE=http://your-elasticsearch-host:9200`
   - Redeploy: `vercel --prod`

#### Important Notes:
- Ensure Elasticsearch is accessible from Vercel's servers
- Consider using Elastic Cloud or a publicly accessible Elasticsearch instance
- Use environment variables for sensitive configuration

---

### Option 2: Docker

Deploy using Docker containers.

#### Create Dockerfile:

```dockerfile
# Create this file: Dockerfile
FROM node:18-alpine AS base

# Install dependencies only when needed
FROM base AS deps
RUN apk add --no-cache libc6-compat
WORKDIR /app

COPY package.json package-lock.json ./
RUN npm ci

# Rebuild the source code only when needed
FROM base AS builder
WORKDIR /app
COPY --from=deps /app/node_modules ./node_modules
COPY . .

ENV NEXT_TELEMETRY_DISABLED=1
RUN npm run build

# Production image, copy all the files and run next
FROM base AS runner
WORKDIR /app

ENV NODE_ENV=production
ENV NEXT_TELEMETRY_DISABLED=1

RUN addgroup --system --gid 1001 nodejs
RUN adduser --system --uid 1001 nextjs

COPY --from=builder /app/public ./public
COPY --from=builder --chown=nextjs:nodejs /app/.next/standalone ./
COPY --from=builder --chown=nextjs:nodejs /app/.next/static ./.next/static

USER nextjs

EXPOSE 3000

ENV PORT=3000
ENV HOSTNAME="0.0.0.0"

CMD ["node", "server.js"]
```

#### Update next.config.ts:

```typescript
import type { NextConfig } from 'next';

const nextConfig: NextConfig = {
  output: 'standalone',
};

export default nextConfig;
```

#### Build and Run:

```bash
# Build the Docker image
docker build -t hasher:latest .

# Run the container
docker run -d \
  -p 3000:3000 \
  -e ELASTICSEARCH_NODE=http://elasticsearch:9200 \
  --name hasher \
  hasher:latest
```

#### Docker Compose:

Create `docker-compose.yml`:

```yaml
version: '3.8'

services:
  app:
    build: .
    ports:
      - "3000:3000"
    environment:
      - ELASTICSEARCH_NODE=http://elasticsearch:9200
    depends_on:
      - elasticsearch
    restart: unless-stopped

  elasticsearch:
    image: docker.elastic.co/elasticsearch/elasticsearch:8.11.0
    environment:
      - discovery.type=single-node
      - xpack.security.enabled=false
      - "ES_JAVA_OPTS=-Xms512m -Xmx512m"
    ports:
      - "9200:9200"
    volumes:
      - elasticsearch-data:/usr/share/elasticsearch/data
    restart: unless-stopped

volumes:
  elasticsearch-data:
```

Run with:
```bash
docker-compose up -d
```

---

### Option 3: Traditional VPS (Ubuntu/Debian)

Deploy to a traditional server.

#### 1. Install Node.js:

```bash
curl -fsSL https://deb.nodesource.com/setup_18.x | sudo -E bash -
sudo apt-get install -y nodejs
```

#### 2. Install PM2 (Process Manager):

```bash
sudo npm install -g pm2
```

#### 3. Clone and Build:

```bash
cd /var/www
git clone <your-repo-url> hasher
cd hasher
npm install
npm run build
```

#### 4. Configure Environment:

```bash
cat > .env.local << EOF
ELASTICSEARCH_NODE=http://localhost:9200
NODE_ENV=production
EOF
```

#### 5. Start with PM2:

```bash
pm2 start npm --name "hasher" -- start
pm2 save
pm2 startup
```

#### 6. Configure Nginx (Optional):

```nginx
server {
    listen 80;
    server_name your-domain.com;

    location / {
        proxy_pass http://localhost:3000;
        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;
    }
}
```

Enable the site:
```bash
sudo ln -s /etc/nginx/sites-available/hasher /etc/nginx/sites-enabled/
sudo nginx -t
sudo systemctl reload nginx
```

---

## Elasticsearch Setup

### Option 1: Elastic Cloud (Managed)

1. Sign up at [Elastic Cloud](https://cloud.elastic.co/)
2. Create a deployment
3. Note the endpoint URL
4. Update `ELASTICSEARCH_NODE` environment variable

### Option 2: Self-Hosted

```bash
# Ubuntu/Debian
wget -qO - https://artifacts.elastic.co/GPG-KEY-elasticsearch | sudo apt-key add -
sudo sh -c 'echo "deb https://artifacts.elastic.co/packages/8.x/apt stable main" > /etc/apt/sources.list.d/elastic-8.x.list'
sudo apt-get update
sudo apt-get install elasticsearch

# Configure
sudo nano /etc/elasticsearch/elasticsearch.yml
# Set: network.host: 0.0.0.0

# Start
sudo systemctl start elasticsearch
sudo systemctl enable elasticsearch
```

---

## Security Considerations

### 1. Elasticsearch Security

- Enable authentication on Elasticsearch
- Use HTTPS for Elasticsearch connection
- Restrict network access with firewall rules
- Update credentials regularly

### 2. Application Security

- Use environment variables for secrets
- Enable HTTPS (SSL/TLS)
- Implement rate limiting
- Add CORS restrictions
- Monitor logs for suspicious activity

### 3. Network Security

```bash
# Example UFW firewall rules
sudo ufw allow 80/tcp
sudo ufw allow 443/tcp
sudo ufw allow from YOUR_IP to any port 9200  # Elasticsearch
sudo ufw enable
```

---

## Monitoring

### Application Monitoring

```bash
# PM2 monitoring
pm2 monit

# View logs
pm2 logs hasher
```

### Elasticsearch Monitoring

```bash
# Health check
curl http://localhost:9200/_cluster/health?pretty

# Index stats
curl http://localhost:9200/hasher/_stats?pretty
```

---

## Backup and Recovery

### Elasticsearch Snapshots

```bash
# Configure snapshot repository
curl -X PUT "localhost:9200/_snapshot/hasher_backup" -H 'Content-Type: application/json' -d'
{
  "type": "fs",
  "settings": {
    "location": "/mnt/backups/elasticsearch"
  }
}'

# Create snapshot
curl -X PUT "localhost:9200/_snapshot/hasher_backup/snapshot_1?wait_for_completion=true"

# Restore snapshot
curl -X POST "localhost:9200/_snapshot/hasher_backup/snapshot_1/_restore"
```

---

## Scaling

### Horizontal Scaling

1. Deploy multiple Next.js instances
2. Use a load balancer (nginx, HAProxy)
3. Share the same Elasticsearch cluster

### Elasticsearch Scaling

1. Add more nodes to the cluster
2. Increase shard count (already set to 10)
3. Use replicas for read scaling

---

## Troubleshooting

### Check Application Status

```bash
pm2 status
pm2 logs hasher --lines 100
```

### Check Elasticsearch

```bash
curl http://localhost:9200/_cluster/health
curl http://localhost:9200/hasher/_count
```

### Common Issues

**Issue**: Cannot connect to Elasticsearch
- Check firewall rules
- Verify Elasticsearch is running
- Check `ELASTICSEARCH_NODE` environment variable

**Issue**: Out of memory
- Increase Node.js memory: `NODE_OPTIONS=--max-old-space-size=4096`
- Increase Elasticsearch heap size

**Issue**: Slow searches
- Add more Elasticsearch nodes
- Optimize queries
- Increase replica count

---

## Performance Optimization

1. **Enable Next.js Static Optimization**
2. **Use CDN for static assets**
3. **Enable Elasticsearch caching**
4. **Configure appropriate JVM heap for Elasticsearch**
5. **Use SSD storage for Elasticsearch**

---

## Support

For deployment issues, check:
- [Next.js Deployment Docs](https://nextjs.org/docs/deployment)
- [Elasticsearch Setup Guide](https://www.elastic.co/guide/en/elasticsearch/reference/current/setup.html)
- Project GitHub Issues