Support for expansion of environment variables in environment variables

Thanks to Support global environment variables it is possible now to define environment variables on a workflow or job level.

What do you think about also allowing expansion of environment variables used in environment variables?

For example, then the following would be possible:

    DOCKER_IMAGE: foo/bar:baz
    DOCKER_RUN: docker run --tty --volume ${PWD}:/usr/src/app ${DOCKER_IMAGE}

name: "List content of working directory"
run: ${DOCKER_RUN} ls -la

Hi @localheinz,

At the moment that is not supported since the yaml is not parsed through a shell to interpret environment variables. However you can use ::set-env to effectively do the same thing. 

Thank you,

Ilya Tillis

Actions Product Manager

::set-env has to be repeated for every job that uses the variable though, right?