send_mail (smtp) from docker-compose (django + nginx + gunicorn)

Question

I am trying to send email via Django. The mail should be sent to the user who would register to our system using Gmail.

I am also using docker-compse django, nginx, gunicorn and postgres.

This is my email configurations inside the django.

EMAIL_BACKEND = 'django.core.mail.backends.smtp.EmailBackend'

EMAIL_HOST = 'smtp.gmail.com'
EMAIL_PORT = '587'
EMAIL_USE_TLS = True

EMAIL_HOST_USER = get_secret("EMAIL_HOST_USER")
EMAIL_HOST_PASSWORD = get_secret("EMAIL_HOST_PASSWORD")
DEFAULT_FROM_EMAIL = EMAIL_HOST_USER

and docker-compose

version: '3.7'

services:
  web:
    build: 
      context: ./dj-psych
      dockerfile: Dockerfile.prod
    command: gunicorn config.wsgi:application --bind 0.0.0.0:8000
    volumes:
      - static_volume:/home/app/web/static/
      - media_volume:/home/app/web/media/
    expose:
      - 8000
    env_file:
      - ./.env.prod
    depends_on:
      - db
  db:
    image: postgres:13.0
    volumes:
      - postgres_data:/var/lib/postgresql/data/
    env_file:
      - ./.env.prod.db
  nginx:
    build: ./nginx
    volumes:
      - static_volume:/home/app/static
      - media_volume:/home/app/static
    ports:
      - server-port:80
    depends_on:
      - web

volumes:
  postgres_data:
  static_volume:
  media_volume:

nginx.conf

upstream config {
    server web:8000;
}

server {

    listen 80;

    location / {
        proxy_pass http://config;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_set_header Host $host;
        proxy_redirect off;
    }

    location /static/ {
        alias /home/app/static/;
    }

    location /media/ {
        alias /home/app/media/;
    }
}

I think the smtp server port (586) should be open in docker.

So I tried binding port web and nginx. But I can't.

how can i do it??

I tried.

from django.core.mail import EmailMessage
email = EmailMessage('subject', 'body', to=['[email protected]'])
email.send()

This is error message

OSError: [Errno 99] Cannot assign requested address

---

The assumption I made is this:

1. The port (8000->80) entering Nginx from Django is responsible for both internal server port 8000 and SMTP port 587. Therefore, both server-related functions and the SMTP service of host port 8000 connected to Nginx must be open.
2. Ports (8000->80) entering Nginx from Django must be assigned internal server port 8000 and SMTP port 587, respectively. There are two external connections (Django-Nginx-host), which should handle 8000 and 587 respectively, and the host port responsible for 587 should have SMTP service open. Can you tell me which one is the right way?