Error when starting the fast api application

[AndreiToader1]

Error when starting the fast api application:

Traceback (most recent call last):
File "project/app.py", line 1, in
from fastapi import FastAPI
File "/project/venv/lib/python3.8/site-packages/fastapi/init.py", line 7, in
from .applications import FastAPI
File "project/venv/lib/python3.8/site-packages/fastapi/applications.py", line 3, in
from fastapi import routing
File "project/venv/lib/python3.8/site-packages/fastapi/routing.py", line 6, in
from fastapi import params
File "project/venv/lib/python3.8/site-packages/fastapi/params.py", line 14, in
class Param(Schema):
TypeError: function() argument 'code' must be code, not str

[prostomarkeloff]

Can you define your environment? Python version and installed packages:

python --version
python -m pip freeze

[RonquilloAeon]

Running into the same issue. I wonder if it's related to Python 3.8 because it started happening when I upgraded my Docker container to python:3.8.0-slim.

Version: Python 3.8.0

Packages:

aiofiles==0.4.0
aiosqlite==0.10.0
asyncpg==0.18.3
ciso8601==2.1.2
Click==7.0
fastapi==0.43.0
h11==0.8.1
httptools==0.0.13
migri==0.1.3
pydantic==1.1.1
PyPika==0.35.16
sqlparse==0.3.0
starlette==0.12.9
tortoise-orm==0.15.1
typing-extensions==3.7.4.1
uvicorn==0.10.8
uvloop==0.14.0
websockets==8.1

[RonquilloAeon]

@AndreiToader1 I found the issue. FastAPI doesn't work w/ pydantic v1. Modifying my requirements to pydantic==0.32.2 solved the problem for me.

See https://gitter.im/tiangolo/fastapi?at=5db558949c39821509922795

[dmontagu]

For what it’s worth, the pydantic v1 was almost certainly the source of the issue, but as of v0.44 fastapi now does support pydantic v1. Be aware there are a number of breaking changes that you may need to address when you upgrade to pydantic v1.

[AndreiToader1]

Sorry for the late response guys. I also solved the problem by changing the version of Pydantic. Since I'm new to python took me a while to figure it out. Thanks

[chamoretto]

Have the same issue after 0.45.0 release.
Installation removed pydantic 0.32.0 and force installing of version 1.2

Collecting fastapi==0.45.0
  Downloading https://files.pythonhosted.org/packages/6b/f4/8aa81e9e5de3877a3149f7e53b21cc3de28d2a474692f17b79b6baf1deb8/fastapi-0.45.0-py3-none-any.whl (43kB)
     |████████████████████████████████| 51kB 469kB/s
Collecting pydantic<2.0.0,>=0.32.2 (from fastapi==0.45.0)
  Using cached https://files.pythonhosted.org/packages/c2/66/b084a7bb0e9762b3e2e03f5051a3f645208e6c8b266e8e253f9b26bf42b9/pydantic-1.2-py36.py37.py38-none-any.whl
Requirement already satisfied: starlette<=0.12.9,>=0.12.9 in c:\users\gosha\appdata\local\packages\pythonsoftwarefoundation.python.3.7_qbz5n2kfra8p0\localcache\local-packages\python37\site-packages (from fastapi==0.45.0) (0.12.9)
Installing collected packages: pydantic, fastapi
  Found existing installation: pydantic 0.32
    Uninstalling pydantic-0.32:
      Successfully uninstalled pydantic-0.32
  Found existing installation: fastapi 0.44.1
    Uninstalling fastapi-0.44.1:
      Successfully uninstalled fastapi-0.44.1
Successfully installed fastapi-0.45.0 pydantic-1.2

And after it i getting this:

Traceback (most recent call last):
  File "C:/Users/gosha/PycharmProjects/nw_backend/main.py", line 4, in <module>
    from newwheel_backend.fastapi_app_instance import app as initial_app
  File "C:\Users\gosha\PycharmProjects\nw_backend\newwheel_backend\fastapi_app_instance.py", line 1, in <module>
    from fastapi import FastAPI
  File "C:\Users\gosha\PycharmProjects\sas\venv\lib\site-packages\fastapi\__init__.py", line 7, in <module>
    from .applications import FastAPI
  File "C:\Users\gosha\PycharmProjects\sas\venv\lib\site-packages\fastapi\applications.py", line 3, in <module>
    from fastapi import routing
  File "C:\Users\gosha\PycharmProjects\sas\venv\lib\site-packages\fastapi\routing.py", line 6, in <module>
    from fastapi import params
  File "C:\Users\gosha\PycharmProjects\sas\venv\lib\site-packages\fastapi\params.py", line 14, in <module>
    class Param(Schema):
TypeError: function() argument 1 must be code, not str

My python version is 3.7.5.

I can solve the problem only by downgrading the version of Pydantic back to 0,32.0.

[dmontagu]

@ShagonRU It looks like there might be something messed up in your environment -- try adding
from fastapi import __version__; print(__version__) somewhere in your fastapi_app_instance.py. And make sure the actual runtime version of fastapi is the same as the version you just installed.

[chamoretto]

@dmontagu
Thank you! Your reply helped me to resolve this issue.
My version was 0.43.0 instead of installer 0.45.0 by some reason...

[tiangolo]

Thanks @prostomarkeloff and @dmontagu for the help here! 🍰 🎉

I think the original problem was solved, right @AndreiToader1 ?

[github-actions[bot]]

Assuming the original issue was solved, it will be automatically closed now. But feel free to add more comments or create new issues.