1. If you need to store API keys or other sensitive information in app.yaml as environment variables for deployment on Google App Engine.
2. If you don't like the idea to push secret environment variables app.yaml to GitHub.
3. If you don't like the idea to store the environment variables in a datastore.

1. Modify the app.yaml file:

    env_variables:
        MY_ENV_VAR1: $MY_ENV_VAR1
        MY_ENV_VAR2: $MY_ENV_VAR2
   

2. Add this action to your workflow:

    - uses: actions/checkout@v1
    - uses: golang-enthusiast/[email protected]
      env:
        MY_ENV_VAR1: ${{ secrets.MY_ENV_VAR1 }}
        MY_ENV_VAR2: ${{ secrets.MY_ENV_VAR2 }}  
   

Note: app.yaml file should be in the root project directory

Full example with deployment to Google App Engine:

deploy:
    name: Deploy
    runs-on: ubuntu-latest
    needs: [build]
steps:
    - uses: actions/checkout@v1
    - uses: golang-enthusiast/[email protected]
      env:
        MY_ENV_VAR1: ${{ secrets.MY_ENV_VAR1 }}
        MY_ENV_VAR2: ${{ secrets.MY_ENV_VAR2 }}              
    - uses: actions-hub/gcloud@master
      env:
        PROJECT_ID: ${{ secrets.GCLOUD_PROJECT_ID }}
        APPLICATION_CREDENTIALS: ${{ secrets.GCLOUD_AUTH }}
        CLOUDSDK_CORE_DISABLE_PROMPTS: 1
      with:
        args: app deploy app.yaml