使用声明式管道执行并行阶段，仅使用列表中的最后一项

Question

我不知道我在这里做错了什么，因为目前当我试图迭代列表时，创建阶段似乎很好，但是在执行seems脚本时，所使用的值始终是列表的最后一项：

工作管道：

pipeline {
    agent any
    stages {
        stage('set servers') {
            steps {
                script {
                    my_list = ['server1','server-2','server-3']
                }
            }
        }
        stage('Execute then') {
            parallel {
                stage('shouter') {
                    steps {            
                        script {
                            shouter = [:]
                            script {
                                for(i in my_list) {
                                    shouter["${i}"] = {
                                        echo "standupandshout.sh ${i}"
                                    }
                                }
                            }                            
                            parallel shouter
                        }
                    }
                }
            }
        }
    }
}

输出：

​

​

控制台输出：

Replayed #4
Running in Durability level: MAX_SURVIVABILITY
[Pipeline] node
Running on Jenkins in /var/lib/jenkins/workspace/test
[Pipeline] {
[Pipeline] stage
[Pipeline] { (set servers)
[Pipeline] script
[Pipeline] {
[Pipeline] }
[Pipeline] // script
[Pipeline] }
[Pipeline] // stage
[Pipeline] stage
[Pipeline] { (Execute then)
[Pipeline] parallel
[Pipeline] [shouter] { (Branch: shouter)
[Pipeline] [shouter] stage
[Pipeline] [shouter] { (shouter)
[Pipeline] [shouter] script
[Pipeline] [shouter] {
[Pipeline] [shouter] script
[Pipeline] [shouter] {
[Pipeline] [shouter] }
[Pipeline] [shouter] // script
[Pipeline] [shouter] parallel
[Pipeline] [server1] { (Branch: server1)
[Pipeline] [server-2] { (Branch: server-2)
[Pipeline] [server-3] { (Branch: server-3)
[Pipeline] [server1] echo
[server1] standupandshout.sh server-3
[Pipeline] [server1] }
[Pipeline] [server-2] echo
[server-2] standupandshout.sh server-3
[Pipeline] [server-2] }
[Pipeline] [server-3] echo
[server-3] standupandshout.sh server-3
[Pipeline] [server-3] }
[Pipeline] [shouter] // parallel
[Pipeline] [shouter] }
[Pipeline] [shouter] // script
[Pipeline] [shouter] }
[Pipeline] [shouter] // stage
[Pipeline] [shouter] }
[Pipeline] // parallel
[Pipeline] }
[Pipeline] // stage
[Pipeline] }
[Pipeline] // node
[Pipeline] End of Pipeline
Finished: SUCCESS

期望输出：

[Pipeline] [server1] echo
[server1] standupandshout.sh server-1
[Pipeline] [server1] }
[Pipeline] [server-2] echo
[server-2] standupandshout.sh server-2
[Pipeline] [server-2] }
[Pipeline] [server-3] echo
[server-3] standupandshout.sh server-3

Answer 1

这是由groovy闭包造成的，当它们包含的代码被计算时。http://blog.freeside.co/2013/03/29/groovy-gotcha-for-loops-and-closure-scope/

当运行闭包时，绑定到变量i的值是它在循环的最后一次迭代中的值，而不是创建闭包的迭代。闭包的作用域具有对i的引用，在执行任何闭包时，I都是5。 循环体局部变量的行为显然不是这样的，因为每个闭包作用域都包含对不同变量的引用。

这就是为什么你的艺名是好的，但你的价值不是。

解决办法是什么？我们应该总是使用.each而不是for循环吗？嗯，在很多情况下，我有点喜欢for循环，并且可能存在内存利用率的差异(不要认为循环“更好”或“更有效”)。 如果您简单地将循环变量化名并在闭包体中引用该别名，那么所有这些都会很好。

def fns = []
for (i in (1..5)) {
    def myi = i
    def isq = i * i
    fns << {->
        println "$myi squared is $isq"
    }
}
fns.each { it() }

所以这应该是可行的：

script {
  shouter = [:]
  for(i in my_list) {
    def val = i
    shouter["${i}"] = {
      echo "standupandshout.sh ${val}"
    }
  }
  parallel shouter
}