Docker - Supervisord container with Nginx (sudo user) - docker

Question

I have created a base image with supervisord installed.
Summary of steps:
FROM ubuntu:20.04
Then I installed some base utilities (time zone/nano/sudo/zip etc)
FROM current_timezone/base-utils:1.04
Then I created a base supervisord image including a user with sudo privileges and password.
RUN apt-get update \
&& groupadd ${DOCKER_CONTAINER_WEBGROUP} -f \
&& useradd -m -s $(which bash) -G sudo ${DOCKER_CONTAINER_USERNAME} \
&& echo "${DOCKER_CONTAINER_USERNAME}:${DOCKER_CONTAINER_PASSWORD}" | chpasswd \
&& usermod -aG www-data ${DOCKER_CONTAINER_USERNAME}
So in any Docker image deriving from this I can run supervisor :
USER ${DOCKER_CONTAINER_USERNAME}
CMD ["/usr/bin/supervisord"]`
So, I have Dockerfile entries for my images deriving from this image :
Apache
Nginx
Varnish
etc
Most of the applications can launch with supervisord like this:
[program:apache2]
command=/bin/bash -c "source /etc/apache2/envvars && exec /usr/sbin/apache2 -DFOREGROUND"
autorestart=false
startretries=0
But Nginx doesn't launch, the error:
the "user" directive makes sense only if the master process runs with super-user privileges, ignored in /etc/nginx/nginx.conf:1
So I created this and thought I would get an input prompt once the container starts: (the objective was to receive input prompt when container starts so that password can be sent to sudo -S to start Nginx)
[program:nginx]
command=sudo -K && read -s -p "Nginx requires a super-privileges (sudo user) to start - Please enter password for your sudo user: " TMP_PW && echo $TMP_PW | sudo -S service nginx start && unset TMP_PW
user=userdefinedinstagesupwards
Running that command above in command-line once I am inside the container already (docker exec -ti container_nginx bash) works, and I can input password from command-line.
The Issues
Nginx does not start automatically, and I have to enter container to start Nginx manually.
NOTE: I have seen the docker nginx image
docker run -d -v $PWD/nginx.conf:/etc/nginx/nginx.conf nginx but this only has Nginx - I have some tools I would like to reuse (as explained above I created an image that has those installed) which means I would have to recreate the steps backwards just for Nginx.
Additional information
As requested below by users, the reasoning why I am using supervisord like this is because I run multiple scripts (debug info/dynamic paths/secrets) and the main application (eg. Apache/Nginx/Varnish) etc alongside.
A simple example: Apache web-server with two files (tried to make a brief example):
When supervisord initializes (CMD ["/usr/bin/supervisord"]) the main application starts, and the helper scripts (in this example some environment variables built from parent images). I can then access all output in /var/log/supervisor/app-stdout(or stderr)* as required.
For instance: I then have information on ${INSTALLED_BASE_APPS_TEXT} available which tells me which apps my base-utils are installed. If I ever see I need to add another tool, for argument here let's say htop, I can go and update the parent image and rebuild this child stage later. Some tools I would always like to be available regardless of which container is running - nano,zip etc are things permanently used by me.
supervisor/conf.d/config-webserver.conf
[supervisord]
nodaemon=true
[program:apache2]
command=/bin/bash -c "source /etc/apache2/envvars && exec /usr/sbin/apache2 -DFOREGROUND"
autorestart=false
startretries=0
supervisor/conf.d/config-information.conf
[program:echo]
command=/bin/bash -c "echo Loaded Supervisord program 'echo' - Stage 5 operation \(Custom Nginx supervisord config\)"
autorestart=false
startretries=1
[program:echo_base_utils]
command=/bin/bash -c "echo ${INSTALLED_BASE_APPS_TEXT}"
autorestart=false
startretries=0
[program:echo_test_item]
command=/bin/bash -c "echo ${ENV_TEST_ITEM}"
autorestart=false
startretries=0
QUESTION
Is there any way that supervisord commands can be made so that they prompt for input as soon as container starts? I would like to keep using the images described above.