如何在流水线中的函数中获取全局变量的值？

# main.py
import os

def get_global_variable():
    return os.getenv('GLOBAL_VAR')

if __name__ == "__main__":
    print(get_global_variable())

# Dockerfile
FROM python:3.8-slim

WORKDIR /app

COPY main.py .

ENV GLOBAL_VAR="Hello, World!"

CMD ["python", "main.py"]

name: CI Pipeline

on: [push]

jobs:
  build:
    runs-on: ubuntu-latest

    steps:
    - name: Checkout code
      uses: actions/checkout@v2

    - name: Set up Docker Buildx
      uses: docker/setup-buildx-action@v1

    - name: Build and push Docker image
      uses: docker/build-push-action@v2
      with:
        context: .
        push: false
        tags: user/app:latest