Retrieving a CI variable from Gitlab project and use it within Dockerfile

Question

I have a CI variable that I would like to use within my docker file. I have tried to include it such as

ENV TESTING_UNIT=$TESTING_ID

Answer 1

It seems like that you need to specify to Dockerfile that it expects an argument variable

With the following approach it will be available in the container

Change:

ENV TESTING_UNIT=$TESTING_ID

To:

ARG TESTING_UNIT_ARG
ENV TESTING_UNIT=$TESTING_UNIT_ARG

and build the image:
docker build --build-arg TESTING_UNIT_ARG=$TESTING_ID