docker-compose not setting environment variables

Question

When I run docker-compose build && docker-compose up redis, with environment specified in docker-compose.yaml and RUN env in the Dockerfile, the environment variables I set don't get printed.

Why does this not work?

I'm using docker-compose version 1.4.2.

Here are the relevant files:

docker-compose.yaml with environment as a list of KEY=value pairs:

redis:
    build: ../storage/redis
    ports:
      - "6379:6379"
    environment:
      - FOO='bar'

docker-compose.yaml with environment as a dictionary:

redis:
    build: ../storage/redis
    ports:
      - "6379:6379"
    environment:
      - FOO: 'bar'

Dockerfile:

FROM redis:2.6
MAINTAINER [email protected]

RUN mkdir -p /var/redis && chown -R redis:redis /var/redis

RUN echo '-------------- env ---------------'
RUN env

COPY redis.conf /usr/local/etc/redis/redis.conf
EXPOSE 6379
ENTRYPOINT ["redis-server", "/usr/local/etc/redis/redis.conf"]

Answer 1

That's normal

docker-compose only sets the environment variables specified in the environment directive in the docker-compose.yaml file during the run phase of the container, and not during the build phase.

So if you do docker-compose run --entrypoint "/bin/bash" redis -c env you will be able to see your env variables.

If you want to set variables inside your Dockerfile (to be able to see them during the build phase) you can add inside your dockerfile before your RUN env:

ENV FOO bar