wsgi.url_scheme http in docker using nginx - django

Question

I am using Apache on CentOS. On this server I have a Django project with docker. There are two containers in docker (nginx and python).
In the Apache I have .conf that have proxy to nginx container that is exposed on port 803. SSL is set in the Apache conf as well.
ProxyPreserveHost On
RequestHeader set X-Forwarded-Proto "https"
RequestHeader set X-Scheme "https"
ProxyPass / http://127.0.0.1:803/
ProxyPassReverse / http://127.0.0.1:803/
On the docker I have app.conf for nginx that looks like this:
upstream project {
server project-python:5000;
}
server {
listen 80;
server_name _;
error_log /var/log/nginx/error.log;
access_log /var/log/nginx/access.log;
client_max_body_size 64M;
location / {
gzip_static on;
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
proxy_set_header Host $http_host;
proxy_set_header X-Scheme "https";
proxy_set_header X-Forwarded-Proto "https";
proxy_set_header X-Forwarded-Protocol "ssl";
proxy_set_header X-Forwarded-Ssl=on;
proxy_set_header Host $host;
proxy_pass http://project;
proxy_redirect off;
}
}
In the Dockerfile Python is exposed on port 5000 and in the docker-compose.prod.yml file for production the python is started with gunicorn with this command:
gunicorn project.wsgi:application --preload --bind 0.0.0.0:5000
So I have two issues.
In the Django when I dump request.META I got wsgi.url_scheme that is http.
The second one is that I don't even understand how nginx is communicating with gunicorn because when I set app.conf to be just like below it is working also. How the nginx know that Python is exposed on port 5000.
server {
listen 80;
server_name _;
error_log /var/log/nginx/error.log;
access_log /var/log/nginx/access.log;
client_max_body_size 64M;
location / {
proxy_pass http://project;
proxy_redirect off;
}
}
docker-compose.yml
version: '3'
services:
project-python:
build:
context: .
dockerfile: docker/python/Dockerfile
container_name: project-python
volumes:
- .:/var/www:rw
- .aws:/home/www/.aws
project-nginx:
build:
context: docker/nginx
dockerfile: Dockerfile
container_name: project-nginx
ports:
- "127.0.0.1:803:80"
depends_on:
- project-python
docker-compose.prod.yml
version: '3'
services:
project-python:
restart: unless-stopped
env_file:
- ./.env.prod
command: gunicorn project.wsgi:application --preload --bind 0.0.0.0:5000
expose:
- 5000
project-nginx:
restart: unless-stopped
environment:
APP_ENV: "production"
APP_NAME: "project-nginx"
APP_DEBUG: "False"
SERVICE_NAME: "project-nginx"