docker-compose cannot start service: “exec: \”python3\": executable file not found

Question

(I'm not deeply experienced with docker , fwiw)

I have a django appication I'm containerizing. Currently when I run docker-compose up the redis service starts up, but api exits with error: ERROR: for api Cannot start service api: OCI runtime create failed: container_linux.go:296: starting container process caused "exec: \\"python3\\": executable file not found in $PATH": unknown

#docker-compose.yaml

version: '3'
services:
  redis:
      image: redis
      ports:
        - 6379
  api:
      build:
        context: ../backend/
        dockerfile: ../backend/Dockerfile
      env_file: .env
      volumes:
          - ../backend:/code/
      ports:
        - "8001:8001"
     depends_on:
        - redis

with

#../backend/Dockerfile
FROM python:3
ENV PYTHONUNBUFFERED 1
RUN mkdir /code
ADD . /code/
WORKDIR /code/
RUN pip install -r requirements.txt
CMD python manage.py runserver

and

#./.env 

DJANGO_SETTINGS_MODULE=backend.settings.dev
DJANGO_SECRET_KEY=<redacted>
SENTRY_URL=<redacted>

I've also, based on other issues, tried using both CMD and RUN with their differing argument types, ie in the existing shell and without, but the output hasn't changed.

I should also acknowledge that it's possible I'm not restarting actually catching the updates to docker-compose.yaml or Dockerfile . My workflow has been $ docker-compose down followed by $ docker-compose up .

EDITS:

@henrik-andersson pointed me in the right direction. The proximate cause of the error is the fact that the image itself was not built, so the executable python didn't exist. the command I needed to run was docker-compose up --build

Answer 1

docker-compose up --build showed that the images were not built. This was fixed by moving the docker-compose.yaml file to the parent directory st the Dockerfile for each service could be accessed properly