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fastmcp.utilities.lifespan

Lifespan utilities for combining async context manager lifespans.

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Functions

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combine_lifespans 

combine_lifespans(*lifespans: Callable[[AppT], AbstractAsyncContextManager[dict[str, Any] | None]]) -> Callable[[AppT], AbstractAsyncContextManager[dict[str, Any]]]
Combine multiple lifespans into a single lifespan. Useful when mounting FastMCP into FastAPI and you need to run both your app’s lifespan and the MCP server’s lifespan. Works with both FastAPI-style lifespans (yield None) and FastMCP-style lifespans (yield dict). Results are merged; later lifespans override earlier ones on key conflicts. Lifespans are entered in order and exited in reverse order (LIFO). Args:
  • *lifespans: Lifespan context manager factories to combine.
Returns:
  • A combined lifespan context manager factory.