Is it possible to use GitHub Action inputs inside the Dockerfile?

Question

I created a GitHub action and am passing input arguments to the action. I am using these arguments in a bash script, which is being called by the Dockerfile . However, it is possible to use any of these inputs in the Dockerfile ?

Specifically I am trying to make the python version a variable input. The Dockerfile is:

FROM python:3
RUN pip install flake8
COPY entrypoint.sh /
RUN chmod +x /entrypoint.sh
ENTRYPOINT ["/entrypoint.sh"]

Where I want the first line to be

FROM python:<github_action_input_arg>

Answer 1

First, I suggest you to use docker/build-push-action@v2 . Then in pipeline, you could use next to pass argument from github actions to Dockerfile:

-
  name: Build and push
  uses: docker/build-push-action@v2
  with:
    context: .
    push: true
    tags: $your_account/$your_repo
    build-args: |
      github_action_input_arg=xxx

Of course, for Dockerfile , you should change to next:

ARG github_action_input_arg
FROM python:${github_action_input_arg}

You could refers to understand-how-arg-and-from-interact & build-push-action . If you mean you are the owner of your own action, you could also refers to build-push-action to know how it handle this.