FastAPI-stream-lease – Redis lease manager for FastAPI SSE/LLM streams (github.com)

A new package, FastAPI-stream-lease, has been announced, allowing developers to manage active Server-Sent Events (SSE), token streams, and WebSocket sessions in FastAPI applications using Redis. This package introduces a unique leasing mechanism that can impose both user-specific and global limits on the number of concurrent streams, responding with HTTP 429 errors when limits are exceeded. This is particularly beneficial for applications where connections can be long-lived, as it enhances resource management and prevents server overload. For the AI/ML community, this tool offers significant implications for building scalable, real-time applications that leverage FastAPI and Redis. FastAPI-stream-lease requires Python 3.10 or later, Redis 5.0 or above, and its client redis-py 4.6.0+. Technically, it utilizes atomic Lua scripts for lease acquisition and renewal, ensuring strong safety guarantees even in the event of transient Redis connection issues. Furthermore, with the option to enable graceful degradation during Redis outages, the package can maintain service availability without losing track of active streams, thereby enhancing the robustness of AI-driven applications.