Docker-compose issue with multiple env_files

Docker Engine Compose
,
1

Hello, not sure if I’m looking at a bug or if things just don’t work this way.
I’m using docker-compose to stand up authentik, postgres, redis.
docker-compose version 1.29.2

First why am I doing the below: I would like to keep the values of passwords/usernames in one location (one .env file) and then reference them from other .env files.

I have seperated out the env vars for the different services into their own .env file.

authentik-server:
    env_file:
      - ./configs/postgresql/.env
      - ./configs/authentik/.env

For postgres/.env:

PG_PASS=Y1JWFVbgU35YlGZ7a3AwVBCFNK3QPyiTCSEqvvNF
PG_USER=postgres
PG_DB=postgres
POSTGRES_USER=${PG_USER}
POSTGRES_PASSWORD=${PG_PASS}
POSTGRES_DB=${PG_DB}
POSTGRES_PORT=5432
POSTGRES_HOST=postgresql

for authentik/.env:

AUTHENTIK_POSTGRESQL__HOST=${POSTGRES_HOST}
AUTHENTIK_POSTGRESQL__USER=${POSTGRES_USER}
AUTHENTIK_POSTGRESQL__PASSWORD=${$POSTGRES_PASSWORD}

The problem I’m running into is the AUTHENTIK_* vars are not assigned the values from the POSTGRES_* vars which are not contained in the same .env file. But the POSTGRES_* vars are assigned the values from the PG_* vars which are in the same .env file. I’m inspecting the env vars by running bash into the authentik-server container and $printenv.

The docs env_file say the order of the env_files matters and I have the postgres/.env listed before the authentik/.env file.

Anther thing I noticed is, if I put the POSTGRES_* AND PG_* VARS in the compose file under environment: as a list they still don’t eval into the AUTHENTIK_* vars.

Thoughts/Suggestions? I maybe trying to do something that docker-compose is not designed for.
Thanks!

2

I doubt that variable substitution works within an .env file. Since you are using it, you must have seen in it in the documentation (or someone else using it like this?). Can you share a link to the section in the documentation where you saw it?