Docker Compose - can I set priority of multiple environment files?

user_17143796 0
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I have a profile in my Compose file like:

  web_prod_db:
    <<: *web
    command: etc. etc.
    env_file:
      - .env
      - .env.prod-db
    profiles:
      - myprofile

I want the values in .env.prod-db to override the (same-named) variables in .env, but this doesn't seem to happen - even if I swap the order that the files are specified so .env.prod-db is specified first.

Is there anything I can do here to ensure the overrides happen as desired?

docker-compose docker
2 Answers

To override values, you can use this approach: https://docs.docker.com/compose/extends/

You can create your main docker-compose.yml file, and others dockerfiles that will override values that you desired. As an example:

docker-compose.yml

web:
  image: example/my_web_app:latest
  depends_on:
    - db
    - cache

db:
  image: postgres:latest

cache:
  image: redis:latest

docker-compose.prod.yml

web:
  ports:
    - 80:80
  environment:
    PRODUCTION: 'true'

cache:
  environment:
    TTL: '500'

And run the command:

docker-compose -f docker-compose.yml -f docker-compose.prod.yml up -d

That will run your containers and will override/merge the values from docker-compose.yml with the values defined in docker-compose.prod.yml

Hope this can be usefull

user_67307200

As stated here:

Environment Files Order: The environment files in the Docker Compose are processed from the top down. For example, for the same variable specified in the file ./common.env and assigned a different value in the file ./apps/db.env, the value from ./apps/db.env stands as this file is listed below (after) the ./common.env file.

So the variable defined for a second time in .env.prod-db takes president over .env

user_100930700
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