ModuleNotFoundError: No module named 'app'

[jmandt]

Hi, the error as mentioned in the title is thrown when running the container. Below I tried to describe my setup in detail.

I have setup everything exactly as described in the readme. Therefore, this is how my Dockerfile looks like.

FROM python:3.10 as requirements-stage

WORKDIR /tmp

RUN pip install poetry

COPY ./pyproject.toml ./poetry.lock* /tmp/

RUN poetry export -f requirements.txt --output requirements.txt --without-hashes

FROM tiangolo/uvicorn-gunicorn-fastapi:python3.10

COPY --from=requirements-stage /tmp/requirements.txt /app/requirements.txt

RUN pip install --no-cache-dir --upgrade -r /app/requirements.txt

COPY ./app /app

my directory structure is as follows.

app
├── main.py
├── api
│  └── __init__.py
|  └── user.py
└── tests
     └── __init__.py
pyproject.toml
Dockerfile

then, in the app/main.py I am trying to import user from the api-directory by doing:
from app.api import user

When running the container, the following error is thrown.
ModuleNotFoundError: No module named 'app'

This is probably because app is not in the PYTHONPATH. I have tried to add it to the Dockerfile, but this did not help.
I want to keep the structure and the way of importing it as is as it is also needed by my test setup.

How can I fix this? The problem has probably a very trivial solution, but I am currently stuck.

Thanks in advance

[JaeHyunL]

I've just had a similar error.
I solved it this way.

My source code directory is app.
DockerFile "COPY"
"./app" "/app" 이라
formed by a structure called /app/app
You change Dockerfile.

COPY . /app

OR

COPY ./app /app_code
WORKDIR /app_code

[tedsecretsource]

@JaeHyunL nailed it! Thank you, whoever you are!

I am using the Heroku container stack. My Dockerfile looked like this:

FROM tiangolo/uvicorn-gunicorn-fastapi:python3.11-slim

COPY ./requirements.txt /app/requirements.txt

RUN pip install --no-cache-dir --upgrade -r /app/requirements.txt

COPY ./app /app

I changed it to this (appended /app on the COPY line):

FROM tiangolo/uvicorn-gunicorn-fastapi:python3.11-slim

COPY ./requirements.txt /app/requirements.txt

RUN pip install --no-cache-dir --upgrade -r /app/requirements.txt

COPY ./app /app/app

Also, FWIW, my heroku.yml file looks like this:

build:
  docker:
    web: Dockerfile
run:
  web: sh /start.sh

[tiangolo]

Now that Uvicorn supports managing workers with --workers, including restarting dead ones, there's no need for Gunicorn. That also means that it's much simpler to build a Docker image from scratch now, I updated the docs to explain it.

Because of that, I deprecated this Docker image: https://github.com/tiangolo/uvicorn-gunicorn-fastapi-docker#-warning-you-probably-dont-need-this-docker-image

That should also make it simpler to copy and setup the Docker image, making it easier to debug as well. 🤓