gitlab CI/CD:如何检查变量但在使用 web UI 时也允许 运行

gitlab CI/CD: How to check for variable but also allow to run when using web UI

我想在触发管道之前检查变量值。但与此同时,我不想在从网络 ui 手动触发时检查变量值

stages:
  - build

build:
  stage: build
  script: 
   - // do something
  only: // HERE WANT TO CHECK THE VARIABLE VALUE WHEN ITS NOT TRIGGERED FROM WEB UI
    variables:
      - $UPSTREAM_PROJECT == "A"
  // BUT HOW TO NOT CHECK THE VARIABLE VALUE WHEN ITS TRIGGERED USING WEB UI

如何操作。

rules: 必须用于此用例。

build:
  rules:
    - if: '$CI_PIPELINE_SOURCE == "web"'
    - if: '$UPSTREAM_PROJECT == "A"'
  # ...