Enhance GaussDB Python Driver Examples with SSL, Logical Replication, and Load Balancing Demos

[pangpang20]

Description

This pull request enhances the GaussDB Python driver repository by adding comprehensive usage examples and improving existing documentation. Key additions include a new SSL setup script, logical replication demo, master-standby and distributed load balancing examples, and detailed READMEs with setup instructions. The changes improve usability, add type safety, and enhance the demonstration of advanced GaussDB features like SSL connections, logical replication, and high-availability scenarios.

Changes Made

• Added README for master-standby usage examples.
• Improved cluster_ha_showcase.py with type hints and better formatting.
• Updated master-standby README to remove hardcoded passwords.
• Added screenshots to example/imgs for visual demonstration.
• Fixed image path separators in master-standby README for cross-platform compatibility.
• Added example/README.md with setup instructions for SSL and non-SSL modes.
• Introduced ssl_demo.py to demonstrate SSL and non-SSL database connections.
• Added README for distributed load balancing demo and logical replication setup.
• Fixed async comprehension in copy tests and applied minor formatting to logical replication demo.
• Simplified OpenGauss SSL setup in README.rst by referencing ssl_opengauss_docker.sh.
• Added ssl_opengauss_docker.sh for streamlined SSL certificate generation and Docker container setup.
• Added logical_replication_demo.py to demonstrate logical replication functionality.
• Removed outdated user creation commands from cluster_opengauss_docker.sh.
• Improved output formatting in demo.py for better readability.
• Added skip markers for unsupported binary copy operations in copy tests.

Why

These changes aim to:

• Improve user experience with clear setup instructions for GaussDB with Docker and SSL.
• Demonstrate advanced features like logical replication and load balancing.
• Enhance code quality with type hints and consistent formatting.
• Ensure security by removing hardcoded credentials and standardizing SSL configurations.
• Improve cross-platform compatibility and documentation clarity with updated image paths and screenshots.

Testing

• Local Testing:

  • Verified SSL setup using ssl_opengauss_docker.sh on a Docker environment.
  • Ran ssl_demo.py with both require and verify-ca SSL modes.
  • Tested logical_replication_demo.py to confirm replication slot creation and CRUD operations.
  • Executed cluster_ha_showcase.py to validate master-standby and load balancing scenarios.
  • Ran pytest to ensure all tests pass, including updated copy tests.

• Environment:

  • Tested on a Linux environment with Docker and Python.
  • Used the latest OpenGauss Docker image.
  • Validated environment variables for correct configuration.