# 502 Error Fixes - Deployment Guide

This guide covers the comprehensive fixes implemented to resolve the 502 errors in the Port Nimara Client Portal.

## Overview of Changes

### 1. Health Check System
- **New Files:**
  - `server/api/health.ts` - Health check endpoint
  - `server/utils/health-checker.ts` - Application readiness management
  - `server/utils/service-checks.ts` - Service availability checks
  - `server/plugins/startup-health.ts` - Startup health monitoring

### 2. Process Management (PM2)
- **New Files:**
  - `ecosystem.config.js` - PM2 configuration with cluster mode
  - `docker-entrypoint.sh` - Custom entrypoint with service checks
- **Modified Files:**
  - `Dockerfile` - Added PM2, health checks, and tini init process

### 3. Nginx Configuration
- **New Files:**
  - `nginx/upstream.conf` - Upstream configuration with health checks
  - `nginx/client.portnimara.dev.conf` - Enhanced Nginx configuration
  - `nginx/error-pages/error-502.html` - Custom 502 error page with auto-retry

### 4. External Service Resilience
- **New Files:**
  - `server/utils/resilient-http.ts` - HTTP client with retry logic and circuit breaker
  - `server/utils/documeso.ts` - Enhanced Documenso client
- **Modified Files:**
  - `server/utils/nocodb.ts` - Updated to use resilient HTTP client

### 5. Memory & Performance Optimization
- **New Files:**
  - `server/plugins/memory-monitor.ts` - Memory usage monitoring
  - `server/utils/cleanup-manager.ts` - Resource cleanup utilities
  - `server/utils/request-queue.ts` - Request queue system

## Deployment Steps

### Step 1: Build Docker Image

```bash
# Build the new Docker image with PM2 support
docker build -t port-nimara-client-portal:resilient .
```

### Step 2: Update Nginx Configuration

1. Copy the new Nginx configuration files to your server:
```bash
# Copy upstream configuration
sudo cp nginx/upstream.conf /etc/nginx/conf.d/

# Copy site configuration
sudo cp nginx/client.portnimara.dev.conf /etc/nginx/sites-available/client.portnimara.dev

# Create error pages directory
sudo mkdir -p /etc/nginx/error-pages
sudo cp nginx/error-pages/error-502.html /etc/nginx/error-pages/

# Test Nginx configuration
sudo nginx -t

# Reload Nginx
sudo nginx -s reload
```

### Step 3: Update Environment Variables

Ensure all required environment variables are set:

```bash
# Required for health checks
NUXT_NOCODB_URL=your-nocodb-url
NUXT_NOCODB_TOKEN=your-nocodb-token
NUXT_MINIO_ACCESS_KEY=your-minio-key
NUXT_MINIO_SECRET_KEY=your-minio-secret
NUXT_DOCUMENSO_API_KEY=your-documenso-key
NUXT_DOCUMENSO_BASE_URL=https://signatures.portnimara.dev

# Optional - for enabling garbage collection monitoring
NODE_OPTIONS="--max-old-space-size=8192 --expose-gc"
```

### Step 4: Deploy with Docker Compose

Create or update your `docker-compose.yml`:

```yaml
version: '3.8'

services:
  client-portal:
    image: port-nimara-client-portal:resilient
    ports:
      - "3028:3000"
    environment:
      - NODE_ENV=production
      - NUXT_NOCODB_URL=${NUXT_NOCODB_URL}
      - NUXT_NOCODB_TOKEN=${NUXT_NOCODB_TOKEN}
      - NUXT_MINIO_ACCESS_KEY=${NUXT_MINIO_ACCESS_KEY}
      - NUXT_MINIO_SECRET_KEY=${NUXT_MINIO_SECRET_KEY}
      - NUXT_DOCUMENSO_API_KEY=${NUXT_DOCUMENSO_API_KEY}
      - NUXT_DOCUMENSO_BASE_URL=${NUXT_DOCUMENSO_BASE_URL}
    volumes:
      - ./logs:/app/logs
    healthcheck:
      test: ["CMD", "curl", "-f", "http://localhost:3000/api/health"]
      interval: 30s
      timeout: 10s
      retries: 3
      start_period: 60s
    restart: unless-stopped
    networks:
      - port-nimara-network

networks:
  port-nimara-network:
    external: true
```

Deploy:
```bash
docker-compose up -d
```

### Step 5: Verify Deployment

1. Check health endpoint:
```bash
curl https://client.portnimara.dev/api/health
```

2. Monitor PM2 processes:
```bash
docker exec -it <container-id> pm2 list
docker exec -it <container-id> pm2 monit
```

3. Check logs:
```bash
# PM2 logs
docker exec -it <container-id> pm2 logs

# Container logs
docker logs -f <container-id>
```

## Monitoring & Maintenance

### Health Check Monitoring

The health endpoint provides comprehensive information:
- Service availability (NocoDB, Directus, MinIO, Documenso)
- Memory usage
- Response times
- Circuit breaker status

### PM2 Commands

```bash
# Inside the container
pm2 list              # List all processes
pm2 monit             # Real-time monitoring
pm2 reload all        # Zero-downtime reload
pm2 logs              # View logs
pm2 flush             # Clear logs
```

### Troubleshooting

1. **If 502 errors persist:**
   - Check `/api/health` to identify failing services
   - Review PM2 logs for crash information
   - Verify all environment variables are set
   - Check Nginx error logs: `sudo tail -f /var/log/nginx/error.log`

2. **High memory usage:**
   - Monitor memory via health endpoint
   - PM2 will auto-restart at 7GB limit
   - Check for memory leaks in logs

3. **Slow responses:**
   - Check circuit breaker status in health endpoint
   - Review queue status for backlogs
   - Monitor external service response times

## Benefits of These Changes

1. **Automatic Recovery:** PM2 cluster mode ensures the app restarts on crashes
2. **Graceful Degradation:** Circuit breakers prevent cascading failures
3. **Better Error Handling:** Retry logic handles temporary failures
4. **Improved Visibility:** Health checks and monitoring provide insights
5. **User Experience:** Custom 502 page with auto-retry improves UX
6. **Resource Management:** Memory monitoring and cleanup prevent leaks

## Rollback Plan

If issues arise:

1. Keep the previous Docker image tagged
2. Revert Nginx configuration:
   ```bash
   sudo cp /etc/nginx/sites-available/client.portnimara.dev.backup /etc/nginx/sites-available/client.portnimara.dev
   sudo nginx -s reload
   ```
3. Deploy previous Docker image:
   ```bash
   docker-compose down
   docker-compose up -d