Set secret variable when using Docker in TravisCI - docker

Question

I build a backend with NodeJS and would like to use TravisCI and Docker to run tests.
In my code, I have a secret env: process.env.SOME_API_KEY
This is my Dockerfile.dev
FROM node:alpine
WORKDIR /app
COPY package.json .
RUN npm install
COPY . .
CMD ["npm", "run", "dev"]
My docker compose:
version: "3"
services:
api:
build:
context: .
dockerfile: Dockerfile.dev
volumes:
- /app/node_modules
- .:/app
ports:
- "3000:3000"
depends_on:
- mongo
mongo:
image: mongo:4.0.6
ports:
- "27017:27017"
And this is my TravisCI
sudo: required
services:
- docker
before_script:
- docker-compose up -d --build
script:
- docker-compose exec api npm run test
I also set SOME_API_KEY='xxx' in my travis setting variables. However, it seems that the container doesn't receive the SOME_API_KEY.
How can I pass the SOME_API_KEY from travisCI to docker? Thanks

Answer 1

Containers in general do not inherit the environment from which they are run. Consider something like this:
export SOMEVARIABLE=somevalue
docker run --rm alpine sh -c 'echo $SOMEVARIABLE'
That will never print out the value of $SOMEVARIABLE because there is no magic process to import environment variables from your local shell into the container. If you want a travis environment variable exposed inside your docker containers, you will need to do that explicitly by creating an appropriate environment block in your docker-compose.yml. For example, I use the following docker-compose.yml:
version: "3"
services:
example:
image: alpine
command: sh -c 'echo $SOMEVARIABLE'
environment:
SOMEVARIABLE: "${SOMEVARIABLE}"
I can then run the following:
export SOMEVARIABLE=somevalue
docker-compose up
And see the following output:
Recreating docker_example_1 ... done
Attaching to docker_example_1
example_1 | somevalue
docker_example_1 exited with code 0
So you will need to write something like:
version: "3"
services:
api:
build:
context: .
dockerfile: Dockerfile.dev
volumes:
- /app/node_modules
- .:/app
ports:
- "3000:3000"
depends_on:
- mongo
environment:
SOME_API_KEY: "${SOME_API_KEY}"
mongo:
image: mongo:4.0.6
ports:
- "27017:27017"

Answer 2

I have a similar issue and solve it passing the environment variable to the container in docker-compose exec command. If the variable is in the Travis environment, you can do:
sudo: required
services:
- docker
before_script:
- docker-compose up -d --build
script:
- docker-compose exec -e SOME_API_KEY=$SOME_API_KEY api npm run test