Design a Cloud Storage Gateway

Functional Requirements:

• Provide a gateway that allows on-premises applications to access cloud storage as if it were local storage.
• Support basic file operations: read, write, delete, list files and directories.
• Support integration with at least one major cloud storage provider (e.g., AWS S3).
• Implement local caching for frequently accessed files to reduce latency.
• Ensure secure data transfer between on-premises and cloud storage (e.g., via HTTPS).
• Provide user authentication and basic access control for file operations.
• Offer simple monitoring/logging for file access and errors.

Non-Functional Requirements:

• The system should be able to handle moderate concurrent access (e.g., tens of users).
• Latency for file access should be low for cached files and reasonable for cloud-backed files.
• The system should be reliable, with minimal data loss in case of failure.
• The gateway should be easy to deploy and configure in a typical enterprise environment.
• Data should be encrypted at rest and in transit.
• The solution should be cost-effective and not require significant additional infrastructure.