Jenkins Pipeline：根据参数设置环境变量

Question

我正在尝试根据传递到作业中的参数在Jenkins管道作业中设置环境变量；这样，我可以在需要它的管道的每个阶段使用环境变量。我尝试在环境块中使用Switch语句：

parameters {
    choice(name: 'ENVIRONMENT', choices: 'dev\nst\nprod', description: 'Environment')
}
environment {
  script {
    switch(env.ENVIRONMENT) {
      case 'dev':
        BRANCH = master
        break
      case 'st':
        BRANCH = 2020Q1
        break 
      case 'prod':
        BRANCH = 2019Q4
        break        
    }
  }
}

然而，这并不起作用，该作业试图将等号之前的所有行评估为KEY名称：

org.codehaus.groovy.control.MultipleCompilationErrorsException: startup failed:
WorkflowScript: 9: "script {
    switch(env.ENVIRONMENT) {
      case 'dev':
        BRANCH" is not a valid identifier and cannot be used for an environment variable. Identifiers must start with a letter or underscore and can contain only letters, numbers or underscores. @ line 9, column 7.
     script {

我该如何让它工作？

Answer 1

实现这一点的方法很少。这是其中之一:

parameters {
   choice(name: 'ENVIRONMENT', choices: 'dev\nst\nprod', description: 'Environment')
}

stages(){
  stage("some stage"){
    steps {
        script{
            switch(env.ENVIRONMENT) {
              case 'dev':
                env.BRANCH = "master"
                break
              case 'st':
                env.BRANCH = "2020Q1"
                break 
              case 'prod':
                env.BRANCH = "2019Q4"
                break        
            }
            withEnv(["BRANCH=${env.BRANCH}"]) {
                ...................................
                ...................................
                ...................................

           }
        }
     }
   }
}