Custom docker-compose.yml

Is it possible to customise the docker-compose.yml file for the underlying containers after install (but before starting)?

I would like to supply some extra Environment Variables to the nginx container and put them on a specific Docker-defined network.

I have tried manually editing, but when ./bitwarden.sh update is run, it overwrites the file back to the default configuration.

So I saw in the ./bwdata/docker/docker-compose.yml file instruction to use an extra docker-compose-override.yml file, to provide additional settings which will be merged at runtime.

Using another thread with a similar Docker configuration to my own, I have the following content in this file:

version: '3'

services:
  nginx:
    environment:
      - VIRTUAL_HOST=sub.domain.com
      - VIRTUAL_PORT=8080
      - LETSENCRYPT_HOST=sub.domain.com
      - [email protected]
    networks:
      webproxy:

networks:
  webproxy:
    external:
      name: nginx-proxy-net

The network is the specific one for my nginx-proxy container. All other containers are on a default network created by Docker Compose. The CNAME DNS entry sub.domain.com exists.

The bitwarden config.yml file has http_port = 8280. The bitwarden-nginx container has a 8280:8080 mapping being applied (not sure where or why it is picking up this specific configuration… My config could allow this to use the default 80/443).

This bitwarden-nginx container does not pick up an IP address. If I run docker ps -a it seems to be restarting constantly. The log file contains:

nginx: [emerg] host not found in upstream "web" in /etc/nginx/conf.d/default.conf:15

Can I view how / what Docker Compose is executing? What does this actual final merged YAML file look like?

If I delete the override.yml file, and update the bitwarden, the bitwarden-nginx container starts with an IP address from the default network and I can access on my LAN, but I will not be able to use my own nginx-proxy configuration.

Any help / pointers please?

Resolved myself, with minor change to the above override file to set the default network for all containers in the stack to be the same nginx-proxy-net with the alternative config:

networks:
  default:
    external:
      name: nginx-proxy-net