GitHub Actions中如何基于下拉选择动态设置Environment的URL值

问题描述 #

我在GitHub Actions中遇到问题：无法基于输入下拉选择设置Environment的url值。我的Workflow配置如下：

# This is a basic workflow to help you get started with running Fortify scans using ScanCentral into Fortify SSC

name: Namelink Scan

# Controls when the workflow will run
on:
  workflow_dispatch:
    inputs:
      choice:
        type: choice
        description: Please select the project to scan
        options:
        - Factorysite
        - HouseSite
env:
    Factorysite: "https://company.com"
    HouseSite: "https://house.com"

# A workflow run is made up of one or more jobs that can run sequentially or in parallel
jobs:
  # This workflow contains a single job called "Scan"
  Scan:
    # The type of runner that the job will run on
    runs-on: windows-latest
    environment:
      name: Test
      url: ${{ env.${{ inputs.choice }} }}
    steps:
      - uses: actions/checkout@v3

运行时出现错误：

The workflow is not valid. .github/workflows/Namelink.yml (Line: 27, Col: 12): Unexpected symbol: '${{'. Located at position 5 within expression: env.${{ inputs.choice

我尝试修改Environment部分的写法，比如改成：

environment:
      name: Test
      url: ${{env.echo ${{ inputs.choice }}}}

但仍然无法解决问题，请问该如何正确实现基于下拉选择动态设置Environment的url值？

解决方案 #

GitHub Actions表达式不支持嵌套的${{ }}语法，要实现动态引用环境变量，需使用方括号属性访问语法：

将environment部分的url字段修改为：

environment:
  name: Test
  url: ${{ env[inputs.choice] }}

关键说明 #

• env在GitHub Actions中是一个对象，当需要通过动态变量作为键名访问其属性时，必须使用对象[动态键名]的形式，对象.静态键名仅适用于固定键名的场景。
• 此前的错误源于嵌套了${{ }}，违反了表达式语法规则；而env.echo的写法也是错误的——echo并非env对象的属性，且无法在表达式中直接执行shell命令。

内容的提问来源于stack exchange，提问作者Mahesh