Environment Variable cannot be found in docker container

Question

I'm trying to setup a docker container on a Ubuntu server for a discord bot.

I have run the following on the Ubuntu server:

export DISCORD_TOKEN = "*****"

sudo docker run --env DISCORD_TOKEN  me/my-docker-repo

In the bot code I have:

import os
TOKEN = os.environ['DISCORD_TOKEN']

when the container is ran it gives the python error "KeyError: 'DISCORD_TOKEN'"

Try adding docker to the current user's user group. Thereafter, login into a new bash session, set the environment variable: `DISCORD_TOKEN` again and run the `docker run` command without sudo. That should fix your problem. — Divij Sehgal, Feb 01 '19 at 20:13
This works Divij Sehgal. It does Warn that the config file cannot be loaded but the container runs now. Thanks! — KGB33, Feb 01 '19 at 20:27
@KGB33 I'll add that as an answer so that you can mark this as closed. — Divij Sehgal, Feb 01 '19 at 21:05

score 2 · Accepted Answer · answered Feb 01 '19 at 21:19

Answer to the original question(From my comment above):

Try adding docker to the current user's user group. Thereafter, login into a new bash session, set the environment variable: DISCORD_TOKEN(and any other variables) again and run the command without sudo as follows:

sudo docker run --env DISCORD_TOKEN  me/my-docker-repo

That should fix your problem.

Reason

This happens because when you start a container with the sudo prefix, it looks not in the current user, but in the root user's environment variable definitions. So without the sudo prefix, it looks in the current user's environment variable definitions.

The other problem regarding load failure of config file, this might help: Docker can’t load config file, but container works fine

score 1 · Answer 2 · answered Feb 02 '19 at 00:44

sudo by default resets the shell environment variables to a minimum set of "known safe" variables. If you use the sudo -E option it will preserve environment variables

sudo -E docker run --env DISCORD_TOKEN  me/my-docker-repo

You can also pass the container-side environment variables directly on the command line, without setting it as such in the parent shell

sudo docker run --env DISCORD_TOKEN="*****" me/my-docker-repo

Environment Variable cannot be found in docker container

2 Answers2