Gunicorn runs by itself but not in docker container

Question

I am trying to run Gunicorn inside a docker container here is my docker file

FROM python:3.6-alpine

RUN pip install gunicorn

COPY . /app

EXPOSE 8000


ENTRYPOINT ["gunicorn", "-c", "/app/etc/gunicorn.py", "backend:app"]

I've tried interchanging backend:app with app:app app:backend etc but nothing works it always errors out and outputs

Failed to find application object 'app' in 'app'

After I build it I run:

docker run -it -p 8000:8000 backend:latest bash

Here is the folder structure from which I copy to /app to.

│   main.py
│   requirements.txt
│
├───backend
│   │   __init__.py
│   │
│   ├───cards
│   │      cards_views.py
│   │      __init__.py
│   │
│
└───etc
        gunicorn.py
        nginx.conf

If I run:

gunicorn -c /backend-flask/etc/gunicorn.py backend:app

Outside of the container it runs perfectly. So it must be something with my folder structure but I cant figure it out.

Answer 1

Adding:

pip install -r /app/requirements.txt

to the Dockerimage file fixed the issue, that and using:

docker run -it --entrypoint=sh [my container]

the final dockerfile looks like:

FROM python:3.6-alpine

RUN pip install gunicorn

COPY . /app

RUN pip install -r /app/requirements.txt

EXPOSE 8000


ENTRYPOINT ["gunicorn", "-c", "/app/etc/gunicorn.py", "backend:app"]