Refactor Database Connection Management and Improve Storage Lifecycle Handling

[ArnoChenFx]

This PR refactors the database connection management for PostgreSQL, Oracle, and TiDB by introducing a ClientManager class. It also enhances the lifecycle management of storage components in LightRAG, ensuring consistency and better maintainability.

Key Changes:

1. Unified Database Initialization for All Backends:

   • Previously, PostgreSQL, Oracle, and TiDB could not be automatically created and configured like other backends when used outside the lightrag_server environment. This update ensures that all backends now exhibit consistent behavior.

2. Decoupled Backend Implementations from lightrag_server:

   • Previously, lightrag_server explicitly imported and initialized PostgreSQL, Oracle, and TiDB, which increased backend maintenance complexity and violated the principle of backend isolation.
   • With this refactor, these backends are now fully self-contained within their respective implementation files, restoring modularity and reducing unnecessary dependencies in the server code.

3. Improved Storage Lifecycle Management:

   • Added initialize() and finalize() methods to StorageNameSpace to handle storage setup and cleanup.
   • LightRAG now explicitly manages storage lifecycle with initialize_storages() and finalize_storages(), ensuring proper resource management.

Benefits:

• Consistent Behavior Across Backends: PostgreSQL, Oracle, and TiDB now behave like other backends, automatically initializing when needed.
• Reduced Maintenance Complexity: Backend implementations are now self-contained, making them easier to maintain and extend.
• Improved Modularity: Decouples backend logic from the server, making the system more flexible and scalable.

Testing:

• Verified that PostgreSQL, Oracle, and TiDB are now automatically initialized and configured correctly.
• Confirmed that storage lifecycle methods are called appropriately during server startup and shutdown.

[YanSte]

Thanks a lot, I will have a look. 🙏🏻

[YanSte]

Really nice feature 🙏🏻

[YanSte]

Let me know when is good I will test it directly.

[ArnoChenFx]

Let me know when is good I will test it directly.

It‘s ready for test!

[YanSte]

Let's go, I merge it. In case of issues we update directly.

[YanSte]

Got some error see my issue: #849