See this StackOverflow question: "GitHub Actions: env: Use pre-defined environment variables on RHS within env section".

I would like to declare some environment variables in a top level env section in my main.yml whose values use some pre-defined environment variables such as those documented in the GitHub Actions documentation. However, it appears I cannot use those pre-defined variables in the right hand side of my env section. For example:

env:
  resourceGroup: ${GITHUB_RUN_ID}${GITHUB_RUN_NUMBER}

Is there a way to make it so any step that needs ${resourceGroup} can get it without having to manually define it within each step?

Use this action as the first step in your workflow, and pass in the JSON-stringified map of env vars that you want set for all steps in the workflow.

test: # make sure the action works on a clean machine without building
  runs-on: ubuntu-latest
  steps:
    - name: Setup env
      uses: jwulf/add-env-vars-action@master
      with:
        map: '{"resourceGroup1": "${{ github.run_id }}-${{ github.run_number }}", "resourceGroup2": "${{ github.run_id }}-${{ github.run_number }}"}'   
    - name: test1
      run: echo ${{ env.resourceGroup1 }}
    - name: test2
      run: echo ${{ env.resourceGroup2 }}