[Solved] Consider this FastAPI lifespan function:async def lifespan(app: FastAPI): print('App is starting') yield print('App is stopping')What output will appear when the app starts and then shuts down? | FastAPI

FastAPI - Middleware and Hooks

Consider this FastAPI lifespan function:

async def lifespan(app: FastAPI):
    print('App is starting')
    yield
    print('App is stopping')

What output will appear when the app starts and then shuts down?

APrints 'App is starting' on startup and 'App is stopping' on shutdown

BPrints both messages immediately on startup

CPrints 'App is stopping' before 'App is starting'

DNo output is printed because yield stops execution

Step-by-Step Solution

Solution:

Step 1: Analyze lifespan function
Code prints before yield on startup, after yield on shutdown.
Step 2: Execution order
On app start: 'App is starting' prints; on shutdown: 'App is stopping' prints.
Final Answer:
Prints 'App is starting' on startup and 'App is stopping' on shutdown -> Option A
Quick Check:
Yield separates startup and shutdown phases [OK]

Quick Trick: Code before yield runs on startup, after yield on shutdown [OK]

Common Mistakes:

MISTAKES

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