I see, that docker-compose run olivetree env call should help, thanks. I think the next thing could try is var substitution in the environment: section. So something like:
docker-compose.yml:
environment:
DATABASE_URL: ecto://olivetree:olivetree@postgres/olivetree
HOSTNAME: localhost
PORT: 4000
GUARDIAN_SECRET_KEY: ${GUARDIAN_SECRET_KEY}
...
(source env vars at command line) OR $ export GUARDIAN_SECRET_KEY=efaw77aw6wfea6f
docker-compose up
You can get it to resolve at runtime by calling it in your code (as opposed to having it in config files, or module attributes, both of which resolve at build time). Some dependencies support taking config options at runtime, like Ecto. If, however, you want to configure eg dependencies using config/config.exs et al at runtime, Distillery supports it either through Config Providers or by setting REPLACE_OS_VARS=true and then defining your config like
config :hello, Hello.Repo,
username: "${DATABASE_USER}",
password: "${DATABASE_PASS}",
hostname: "${DATABASE_HOST}",
database: "${DATABASE_NAME}",
port: "${DATABASE_PORT}",
pool_size: 15
replace with your own options and env variables.
There’s more information in the DIstillery guide for working with Docker Deploying With Docker - Distillery Documentation
Yeah, thanks for reminding me of Config Providers. I may end up needing to stop fighting Docker and use that instead.
EDIT: there are some good tips in there about using docker-compose too, guess I’ll try that first.