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Deployment Overview

This page provides an overview of the DocuSnap-Backend system deployment in a production environment, including deployment architecture, component relationships, and key considerations.

Deployment Architecture

The DocuSnap-Backend system adopts a layered deployment architecture, separating different functional components to improve system scalability, reliability, and maintainability. The overall deployment architecture is shown in the following diagram:

Deployment Architecture Diagram

This deployment architecture includes the following main components:

  1. Client Layer:
  2. Web clients
  3. Mobile clients

  4. Third-party applications

  5. Load Balancing Layer:

  6. Nginx reverse proxy

  7. Load balancer

  8. Application Service Layer:

  9. Flask application instances

  10. Gunicorn WSGI server

  11. OCR Service Layer:

  12. CnOCR service instances

  13. Data Storage Layer:

  14. SQLite database

  15. File storage

  16. External Service Layer:

  17. Zhipu AI LLM service

Deployment Modes

The DocuSnap-Backend system supports the following deployment modes:

1. Single-Server Deployment

Suitable for development, testing, and small-scale usage scenarios.

Characteristics: - All components deployed on a single server - Simple to deploy and maintain - Shared resources, low cost - Suitable for low concurrency, low load scenarios

Deployment Steps: 1. Install necessary dependencies (Python, Flask, SQLite, etc.) 2. Clone the repository and configure the environment 3. Start the Flask application and OCR service 4. Configure Nginx as a reverse proxy (optional)

2. Distributed Deployment

Suitable for production environments and large-scale usage scenarios.

Characteristics: - Components distributed across multiple servers - Can scale each component independently - Improves system reliability and fault tolerance - Suitable for high concurrency, high load scenarios

Deployment Steps: 1. Deploy load balancing layer (Nginx) 2. Deploy multiple application service instances 3. Deploy multiple OCR service instances 4. Configure data storage layer 5. Configure external service connections

3. Containerized Deployment

Using container technologies such as Docker and Kubernetes for deployment.

Characteristics: - Environment consistency and isolation - Facilitates automated deployment and scaling - High resource utilization - Suitable for cloud environments and microservice architectures

Deployment Steps: 1. Create Docker images (application service, OCR service) 2. Write Docker Compose or Kubernetes configurations 3. Deploy container orchestration system 4. Configure service discovery and load balancing

Deployment Requirements

Hardware Requirements

Minimum Configuration (Single-server deployment): - CPU: 4 cores - Memory: 8 GB - Storage: 50 GB SSD - Network: 100 Mbps

Recommended Configuration (Distributed deployment): - Application Server: - CPU: 8+ cores - Memory: 16+ GB - Storage: 100+ GB SSD - Network: 1+ Gbps - OCR Server: - CPU: 8+ cores - Memory: 16+ GB (GPU version requires GPU support) - Storage: 100+ GB SSD - Network: 1+ Gbps

Software Requirements

Operating System: - Linux (recommended Ubuntu 20.04+ or CentOS 8+) - Windows Server supported, but not recommended for production environments

Runtime Environment: - Python 3.8+ - pip 20.0+ - virtualenv or conda (recommended)

Web Server: - Nginx 1.18+ - Gunicorn 20.0+

Database: - SQLite 3.30+ (default) - Optional: PostgreSQL 12+ (recommended for large-scale deployments)

Container Platform (optional): - Docker 19.0+ - Docker Compose 1.25+ - Kubernetes 1.18+ (recommended for distributed deployments)

Network Configuration

Port Configuration

External Ports: - HTTP: 80 (redirects to HTTPS) - HTTPS: 443

Internal Ports: - Flask application: 5000 (default) - Gunicorn: 8000 (default) - OCR service: 5001 (default)

Network Security

Recommended Configuration: - Enable HTTPS, using TLS 1.2+ - Configure appropriate CORS policies - Use Web Application Firewall (WAF) - Implement IP restrictions and access controls - Regularly update security patches

Scalability Considerations

The DocuSnap-Backend system design supports both horizontal and vertical scaling:

Horizontal Scaling

  • Application Service Layer:
  • Increase the number of application service instances
  • Use load balancing to distribute requests

  • Stateless design facilitates scaling

  • OCR Service Layer:

  • Increase the number of OCR service instances
  • Use load balancing to distribute requests
  • Can be scaled on demand

Vertical Scaling

  • Increase Single Machine Resources:
  • Upgrade CPU, memory, and storage
  • Suitable for low to medium load scenarios
  • Simple to implement, but limited scalability

Database Scaling

  • SQLite Limitations:
  • Suitable for small to medium-scale deployments
  • Limited concurrent write performance

  • Does not support distributed deployment

  • Upgrade to PostgreSQL (recommended for large-scale deployments):

  • Supports high concurrent read and write operations
  • Supports master-slave replication and sharding
  • Better data management and backup mechanisms

Monitoring and Maintenance

Monitoring Metrics

System Metrics: - CPU usage - Memory usage - Disk I/O - Network traffic

Application Metrics: - Request response time - Request success rate - Task queue length - Task processing time - OCR and LLM service response times

Log Management

Log Types: - Application logs - Access logs - Error logs - Security logs

Log Configuration: - Use structured log formats (such as JSON) - Configure appropriate log levels - Implement log rotation policies - Consider using centralized log management systems (such as ELK stack)

Backup Strategy

Backup Content: - Database files - Configuration files - Key files - Application code

Backup Frequency: - Database: Daily incremental backups, weekly full backups - Configuration and keys: Backup after each modification - Application code: Backup before each deployment

Deployment Checklist

The following is a high-level checklist for deploying the DocuSnap-Backend system:

  1. Prepare Environment:
  2. Set up servers and network
  3. Install necessary software and dependencies

  4. Configure firewall and security policies

  5. Deploy Application Service:

  6. Clone the repository
  7. Configure environment variables and configuration files
  8. Install Python dependencies

  9. Set up Gunicorn and Nginx

  10. Deploy OCR Service:

  11. Install CnOCR and its dependencies
  12. Configure OCR service

  13. Set up service auto-start

  14. Configure Database:

  15. Initialize SQLite database
  16. Set database permissions

  17. Configure backup strategy

  18. Configure External Services:

  19. Set up Zhipu AI API keys
  20. Configure connection parameters

  21. Test connections

  22. Set Up Monitoring:

  23. Configure system monitoring
  24. Set up application monitoring

  25. Configure alert mechanisms

  26. Test and Verify:

  27. Functional testing
  28. Performance testing

  29. Security testing

  30. Go Live:

  31. Switch traffic
  32. Monitor system status
  33. Prepare rollback plan

Through this layered deployment architecture and flexible deployment modes, the DocuSnap-Backend system can adapt to usage scenarios of different scales and requirements, providing efficient and reliable document and form processing services.