bug: TypeError: Router.__init__() got an unexpected keyword argument 'on_startup' (Starlette 1.0.0 incompatibility)

[sarang-26]

Since the release of Starlette 1.0.0 on March 22, 2026, the webui-pipelines image is crashing on startup. This is due to a breaking change in Starlette where the on_startup argument was removed, which is still being passed by older versions of FastAPI or internal application logic.

File "/app/main.py", line 257, in
app = FastAPI(docs_url="/docs", redoc_url=None, lifespan=lifespan)
...
File "/usr/local/lib/python3.11/site-packages/fastapi/routing.py", line 787, in init
super().init(
TypeError: Router.init() got an unexpected keyword argument 'on_startup'

We need to pin the starlette to a compatible version.

[Amirka-Kh]

You can clean all version requirements:

starlette
fastapi
uvicorn[standard]
pydantic
python-multipart
python-socketio
grpcio
...

in requirements.txt and requirements-minimum.txt
it worked for me