I have a Python program that uses the Docker Python SDK to run a container for a third-party docker image. Something like that in my code:
import docker
docker.from_env().containers.run(image="<other_image>")
My program is also packaged in Docker, and I would like to test with gitlab CI. So my .gitlab-ci.yml looks like that:
image: <my_image>:latest
stages:
- Tests
pytest:
stage: Tests
script:
- pytest
And the python code from above is covered by the tests. The problem is that the CI fails on docker.from_env() with docker.errors.DockerException: Error while fetching server API version: ('Connection aborted.', FileNotFoundError(2, 'No such file or directory')).
I assume that is because there's no docker server accessible from within <my_image> container. I searched for solutions, and I found the docker:dind one + the "expose docker socket" i.e. /var/run/docker.sock:/var/run/docker.sock one, but I can't make it work.
All the examples that I found for docker:dind are for calling docker directly in the .gitlab-ci.yml, but I have found none that explains how to leverage it for using a Docker SDK in your own code. Also, the socket solution requires you to change the gitlab runner configuration, but I don't have access to it (I am using a gitlab free account and don't have the opportunity to host my own runner).
What I need is basically:
image:
name: <my_image>:latest
volumes:
- /var/run/docker.sock:/var/run/docker.sock
But AFAIK it doesn't exist.
Is there any solution?
Update: I realize that this would actually work:
image: docker
services:
- docker:dind
stages:
- Tests
pytest:
stage: Tests
script:
- docker run -v /var/run/docker.sock:/var/run/docker.sock <my_image>:latest pytest
But I would still be interested to know if it's possible to do it while still using my image as the base (for example, maybe I don't want to have pytest installed in my image, but I would do it with a before_script instruction in .gitlab-ci.yml... this I could also do in a script to be executed instead of running pytest directly, so I agree that this might not be a very good reason).
