无法基于YAML参数设置变量，请求协助并咨询多变量声明可行性

原代码的核心问题 #

1. 缺失parameters顶层块：直接定义参数项但未包裹在parameters:下，导致参数无法被正确识别。
2. 变量条件判断语法错误：在eq()函数里嵌套了${{ }}表达式，正确写法是直接引用parameters.azure_subscription，无需额外表达式包裹。
3. Stage中Pool的缩进错误：两个条件判断块缩进不一致，引发YAML结构解析失败。
4. 未覆盖全参数分支：service-connection-tes和service-connection-prd的情况未定义对应key_vault变量，可能导致后续执行错误。

修正后的完整YAML代码 #

parameters:
- name: azure_subscription
  displayName: "Select subscription"
  type: string
  default: "service-connection-dev"
  values: 
    - 'service-connection-dev' 
    - 'service-connection-sit'
    - 'service-connection-tes'
    - 'service-connection-prd'

variables:
- ${{ if eq(parameters.azure_subscription, 'service-connection-sit') }}:
  - name: key_vault
    value: 'core-kv-sit'
  - name: additional_var1
    value: 'sit-custom-value-1'
  - name: additional_var2
    value: 'sit-custom-value-2'
- ${{ if eq(parameters.azure_subscription, 'service-connection-dev') }}:
  - name: key_vault
    value: 'core-kv-dev'
  - name: additional_var1
    value: 'dev-custom-value-1'
  - name: additional_var2
    value: 'dev-custom-value-2'
- ${{ if eq(parameters.azure_subscription, 'service-connection-tes') }}:
  - name: key_vault
    value: 'core-kv-tes'
  - name: additional_var1
    value: 'tes-custom-value-1'
  - name: additional_var2
    value: 'tes-custom-value-2'
- ${{ if eq(parameters.azure_subscription, 'service-connection-prd') }}:
  - name: key_vault
    value: 'core-kv-prd'
  - name: additional_var1
    value: 'prd-custom-value-1'
  - name: additional_var2
    value: 'prd-custom-value-2'

stages:
- stage: Validate
  ${{ if eq(parameters.azure_subscription, 'service-connection-dev') }}:
    pool:
      name: agent-pool-win-dev
  ${{ if eq(parameters.azure_subscription, 'service-connection-sit') }}:
    pool:
      name: agent-pool-win-sit
  ${{ if eq(parameters.azure_subscription, 'service-connection-tes') }}:
    pool:
      name: agent-pool-win-tes # 替换为实际测试环境代理池名称
  ${{ if eq(parameters.azure_subscription, 'service-connection-prd') }}:
    pool:
      name: agent-pool-win-prd # 替换为实际生产环境代理池名称

  jobs:
  - job: Validate
    steps:
    - task: AzureKeyVault@2
      inputs:
        KeyVaultName: "${{ variables.key_vault }}"
        SecretsFilter: "*"
        RunAsPreJob: false
        azureSubscription: ${{ parameters.azure_subscription }}
    # 验证新增变量的输出
    - script: |
        echo 自定义变量1: $(additional_var1)
        echo 自定义变量2: $(additional_var2)

关键修正点说明 #

1. 补全parameters块：将参数定义放在parameters:下，确保Azure DevOps正确识别参数配置。
2. 修正条件判断语法：移除表达式嵌套，直接使用eq(parameters.azure_subscription, '目标值')的正确写法。
3. 统一缩进格式：所有条件判断块保持相同缩进层级，保证YAML结构合法。
4. 支持多变量声明：在每个参数分支下可直接新增任意数量的变量，完全满足根据参数输入定义多变量的需求。

优化写法（可选） #

如果参数与变量的映射关系规整，可使用对象映射简化代码，减少重复的if判断：

variables:
- name: env_config
  value:
    service-connection-dev:
      key_vault: 'core-kv-dev'
      pool: 'agent-pool-win-dev'
      additional_var1: 'dev-custom-value-1'
      additional_var2: 'dev-custom-value-2'
    service-connection-sit:
      key_vault: 'core-kv-sit'
      pool: 'agent-pool-win-sit'
      additional_var1: 'sit-custom-value-1'
      additional_var2: 'sit-custom-value-2'
    service-connection-tes:
      key_vault: 'core-kv-tes'
      pool: 'agent-pool-win-tes'
      additional_var1: 'tes-custom-value-1'
      additional_var2: 'tes-custom-value-2'
    service-connection-prd:
      key_vault: 'core-kv-prd'
      pool: 'agent-pool-win-prd'
      additional_var1: 'prd-custom-value-1'
      additional_var2: 'prd-custom-value-2'
- name: key_vault
  value: ${{ variables.env_config[parameters.azure_subscription].key_vault }}
- name: pool_name
  value: ${{ variables.env_config[parameters.azure_subscription].pool }}
- name: additional_var1
  value: ${{ variables.env_config[parameters.azure_subscription].additional_var1 }}
- name: additional_var2
  value: ${{ variables.env_config[parameters.azure_subscription].additional_var2 }}

stages:
- stage: Validate
  pool:
    name: ${{ variables.pool_name }}
  jobs:
  - job: Validate
    steps:
    - task: AzureKeyVault@2
      inputs:
        KeyVaultName: "${{ variables.key_vault }}"
        SecretsFilter: "*"
        RunAsPreJob: false
        azureSubscription: ${{ parameters.azure_subscription }}

这种写法更易维护，新增环境或变量时只需修改映射对象即可。

内容的提问来源于stack exchange，提问作者P Kishan