Environment variables in Django container not being properly set

[davidwilby]

There's some problem with the environment variables file and the entrypoint script for the django service, resulting in:

CELERY_BROKER_URL taking it's value from reprohack_site/.envs/.local/.django, due to the line:

CELERY_BROKER_URL=REDIS_URL

and not being set by entrypoint for some reason.

similarly, this line is not being executed correctly, so DATABASE_URL is not set, meaning that a whole range of django db commands can't be run incl. createsuperuser and migrate

export DATABASE_URL="postgis://${POSTGRES_USER}:${POSTGRES_PASSWORD}@${POSTGRES_HOST}:${POSTGRES_PORT}/${POSTGRES_DB}"

[willfurnass]

I don't see how that line can be right: seems that it should really be something like:

CELERY_BROKER_URL="${REDIS_URL}"

[willfurnass]

Re the DATABASE_URL not being set: this looks pertinent: cookiecutter/cookiecutter-django#2848

[davidwilby]

CELERY_BROKER_URL=REDIS_URL is in the env variable file, but there's a note elsewhere (I think in the entrypoint) about how you can't do variable expansion in env variable files.

But it seemed to me that when running the local stack that the entrypoint script was not executing correctly as none of the environment variables set therein were actually set.

[griff-rees]

If memory serves stuff of this ilk came up when trying to sort this:

cookiecutter/cookiecutter-django#1888
cookiecutter/cookiecutter-django#2712
cookiecutter/cookiecutter-django#2413 (comment)

so it may be possible to alter the configuration, perhaps in line with this change: cookiecutter/cookiecutter-django#2674

[Joe-Heffer-Shef]

So, it looks like the environment variables set in the entrypoint script aren't being remembered because it's a different shell. I don't think it's the best idea to set environment variables in this way, see: Environment variables in Compose

I'm not sure the Django container is actually running the /entrypoint script because the compose file defines the command option (which is equivalent to the CMD statement in a Dockerfile) like this command: /start as shown here https://github.com/reprohack/reprohack_site/blob/dev/local.yml#L24

The /start script doesn't set the DATABASE_URL environment variable.

I believe that Docker Compose will only use the entrypoint/ENTRYPOINT script when using docker-compose run and will run the command/CMD script (and not the entrypoint script) when using docker-compose up.

From Docker RUN vs CMD vs ENTRYPOINT:

ENTRYPOINT instruction allows you to configure a container that will run as an executable. It looks similar to CMD, because it also allows you to specify a command with parameters.

[Joe-Heffer-Shef]

By the way, passwords should probably not be stored in an environment variable.

See: Manage sensitive data with Docker secrets

[Joe-Heffer-Shef]

Proposed fix Joe-Heffer-Shef@9747be2