Setting up dockerized Couchdb with python

Question

Long story short I need to extend apache/couchdb/ Dockerfile so that would do some magic processing to get 2 values (username and password) and then start the couchdb instance with an admin.

Normally you would do it by running docker run ... -e COUCHDB_USER=admin -e COUCHDB_PASSWORD=password couchdb but I may not know the values beforehand and I want those to be retrieve from somewhere every time container is starting.

I made a Dockerfile that looks more or less like this:

FROM couchdb:2.1.1
RUN apt-get update --force-yes && apt-get install -y python3
RUN curl https://bootstrap.pypa.io/get-pip.py | python3
ADD . /app
RUN pip install -r /app/requirements.txt
CMD ["python3", "/app/start_couch.py"]

Where start_couch.py looks like this:

import os
import subprocess

user,password = very_complex_stuff()

os.environ['COUCHDB_USER'] = user
os.environ['COUCHDB_PASSWORD'] = password

subprocess.call(["/opt/couchdb/bin/couchdb"], env=os.environ)

yet when build and run my image the couchdb starts without an pre-set admin (I mean i can do everything without login)

Can someone point out what am i doing wrong or suggest a different solution?

The criteria is that admin credentials are taken from a python script (function) and it needs to executed on docker run

Answer 1

Mistery solved

that image have a custom entrypoint ENTRYPOINT ["tini", "--", "/docker-entrypoint.sh"], so the -e switch sets up env vars before the .sh is execute however my python script is run later.

I fix this by changing adding to Dockerfile

ENTRYPOINT ["tini", "--"]
CMD ["python3", "/app/start_couch.py"]

and calling couch from python like this:

subprocess.call(
    ["/docker-entrypoint.sh", "/opt/couchdb/bin/couchdb"],
    env=os.environ
)