Description
A ContextVar set within a lifespan context manager is not available inside request handlers. By contrast, doing the same thing via an application level dependency does appear set in the require handler.
MCVE
import asyncio
from collections.abc import AsyncIterator
from contextlib import asynccontextmanager
from contextvars import ContextVar
from litestar import Litestar
from litestar import get
from litestar.testing import AsyncTestClient
VAR = ContextVar[int]("VAR", default=0)
@asynccontextmanager
async def set_var() -> AsyncIterator[None]:
token = VAR.set(1)
try:
yield
finally:
VAR.reset(token)
@get("/example")
async def example() -> int:
return VAR.get()
app = Litestar([example], lifespan=[set_var()])
async def test() -> None:
async with AsyncTestClient(app) as client:
response = await client.get("/example")
assert (value := response.json()) == 1, f"Expected 1, got {value}"
if __name__ == "__main__":
asyncio.run(test())Steps to reproduce
Run the example above. Either via python example.py or uvicorn example:app and check the /example route.
We should expect the response to be 1 since that's what's set during the lifespan context manager, but it's always 0.
If you instead swap the lifespan context manager for a dependency it works as expected:
import asyncio
from collections.abc import AsyncIterator
from contextvars import ContextVar
from litestar import Litestar
from litestar import get
from litestar.testing import AsyncTestClient
VAR = ContextVar[int]("VAR", default=0)
async def set_var() -> AsyncIterator[None]:
token = VAR.set(1)
try:
yield
finally:
VAR.reset(token)
@get("/example")
async def example(set_var: None) -> int:
return VAR.get()
app = Litestar([example], dependencies={"set_var": set_var})
async def test() -> None:
async with AsyncTestClient(app) as client:
response = await client.get("/example")
assert (value := response.json()) == 1, f"Expected 1, got {value}"
if __name__ == "__main__":
asyncio.run(test())Litestar Version
2.12.1
Platform
- Linux
- Mac
- Windows
- Other (Please specify in the description above)
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