fix: Lifespan pr cleanup/Extending ASGI lifespan examples #1534
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Fixes modelcontextprotocol#1484 - Add contextlib import and lifespan function to all mounting examples - Add stateless_http=True parameter to FastMCP constructors - Add lifespan=lifespan parameter to Starlette apps - Update README.md documentation with correct examples - Fixes RuntimeError: Task group is not initialized. Make sure to use run() Resolves the issue where mounting StreamableHTTP servers to existing ASGI applications would fail with RuntimeError due to missing session manager initialization.
Run scripts/update_readme_snippets.py to sync documentation with code changes.
…lifespan Extend Fix/streamable http mounting lifespan
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Removed the stateless http additions by @ranjitodedra as they weren't necessary for the issue and may add confusion as stateless_http isn't necessary for a streamable http mcp service.
Motivation and Context
Fixing #1494 and also added an example with more detailed explanation of attaching ASGI services through lifespan.
How Has This Been Tested?
I tested the new example with information from #1484. The main issue was attempting to run two separate ASGI services at the same time rather than mounting them to a main one to call other ASGI services.
Breaking Changes
No there are no breaking changes just documentation and examples.
Types of changes
Checklist
Additional context
As was said in Issue #1494 they found they could mount existing server routes onto an mcp server but were struggling on the configuration to run multiple services asynchronously. It is possible to do so with Starlette examples, the mcp service, as well as other asynchronous services can be started and stopped by a context manager lifespan function, on a Starlette app call.
The confusion with stateless_http is probably that a streamable_http mcp server requires stateless_http due to its name, unless you look deeper you won't find that it is only tied to if requests track sessions or carry persistence between requests. I removed the added stateless_http since it wasn't necessary for the examples in question.