Want to run python script and Flask api from single Dockerfile

Question

I am trying to create container with following docker file. Since it is going to execute last CMD, it ignores CMD ["sh", "-c", "python3 run_scheduler.py --config=${config}"] . Is there a way to run both from single docker file. Also, is it possible to pass ${config} argument to flask api in CMD ["gunicorn", "--bind", "0.0.0.0:5000", "run_api:application", "&"]

FROM python:3.8

LABEL version="0.1"

WORKDIR /app
COPY . /app

ARG config=dev
RUN  pip install -r requirements.txt
EXPOSE 5000
CMD ["sh", "-c", "python3 run_scheduler.py --config=${config}"]
CMD ["gunicorn",  "--bind", "0.0.0.0:5000",  "run_api:application", "&"]

Answer 1

As mentioned in comments you can pass 2-line bash script in CMD. This can cause problems however. Docker is not really meant to run multiple processes in single container. I already see "&" argument in your second CMD. I guess you had problems with second process wasn't running so you tried to push it to the background.

The solution recommended by Docker is to run supervisord inside the container: https://docs.docker.com/config/containers/multi-service_container/

From naming concepts I guess you can solve your problem with Flask-APScheduler https://github.com/viniciuschiele/flask-apscheduler This way you can get rid of second sidecar script.

And lastly you asked:

Also, is it possible to pass ${config} argument to flask api

and answer is yes. Declare ENV in your Dockerfile like so:

FROM python:3.8
...
...
ENV config foo
...
CMD ["whatever_command", "--option", "${config}"]

This way "${config}" will be replaced with value foo .