如何在Jenkins声明式流水线阶段锁中使用运行时环境变量

问题场景 #

配置Jenkins声明式流水线的阶段锁时，希望使用前置阶段设置的运行时环境变量作为锁资源名称，但直接使用${env.MYVAR}时，锁名称显示为null。

原始测试流水线代码 #

import hudson.console.*

pipeline {
    agent none
    stages {
        stage('Init') {
            stages{
                stage('init_1') {
                    steps {
                        script {
                          env.MYVAR = "value"
                        }
                    }
                }
                stage('init_2') {
                    steps {
                        print("${env.MYVAR}")
                    }
                   // other init stuff
                }
            }
        }

        stage('run') {
            agent any

            options {
                lock resource: "${env.MYVAR}"
            }

            stages {
                stage('actually do stuff') {
                    steps {
                        print("${env.MYVAR}")
                    }
                }
            }
        }
    }
}

执行输出日志 #

10:30:47  [Pipeline] Start of Pipeline
10:30:47  [Pipeline] stage
10:30:47  [Pipeline] { (Init)
10:30:47  [Pipeline] stage
10:30:47  [Pipeline] { (init_1)
10:30:47  [Pipeline] script
10:30:47  [Pipeline] {
10:30:47  [Pipeline] }
10:30:47  [Pipeline] // script
10:30:47  [Pipeline] }
10:30:47  [Pipeline] // stage
10:30:47  [Pipeline] stage
10:30:47  [Pipeline] { (init_2)
10:30:47  [Pipeline] echo
10:30:47  value
10:30:47  [Pipeline] }
10:30:47  [Pipeline] // stage
10:30:47  [Pipeline] }
10:30:47  [Pipeline] // stage
10:30:47  [Pipeline] stage
10:30:47  [Pipeline] { (run)
10:30:47  [Pipeline] lock
10:30:47  Trying to acquire lock on [null]
10:30:47  Resource [null] did not exist. Created.
10:30:47  Lock acquired on [null]
10:30:47  [Pipeline] {
10:30:48  [Pipeline] node
10:30:48  Running on Jenkins in /var/jenkins_home/workspace/Pipeline for tests
10:30:48  [Pipeline] {
10:30:48  [Pipeline] stage
10:30:48  [Pipeline] { (actually do stuff)
10:30:48  [Pipeline] echo
10:30:48  value
10:30:48  [Pipeline] }
10:30:48  [Pipeline] // stage
10:30:48  [Pipeline] }
10:30:48  [Pipeline] // node
10:30:48  [Pipeline] }
10:30:48  Lock released on resource [null]
10:30:48  [Pipeline] // lock
10:30:48  [Pipeline] }
10:30:48  [Pipeline] // stage
10:30:48  [Pipeline] End of Pipeline
10:30:48  Finished: SUCCESS

问题原因 #

声明式流水线的options块属于流水线的初始化配置阶段，会在流水线开始执行任何阶段前就被解析。而原始代码中env.MYVAR是在Init阶段内设置的，此时options块已经完成解析，所以无法获取到该变量值，导致锁名称为null。

解决方案 #

将环境变量的初始化逻辑移到pipeline块外部的node中执行，这样变量会在流水线解析前就被设置到全局环境里，后续options块就能正确读取到变量值。

修改后的适配代码 #

import hudson.console.*

node {
    stage('init_1') {
        script {
            env.MYVAR = "value"
        }
    }
}

pipeline {
    agent none
    stages {
        stage('Init') {
            stages{
                stage('init_2') {
                    steps {
                        print("${env.MYVAR}")
                    }
                   // other init stuff
                }
            }
        }
        stage('run') {
            agent any

            options {
                lock(resource: "${env.MYVAR}")
            }

            stages {
                stage('actually do stuff') {
                    steps {
                        print("${env.MYVAR}")
                    }
                }
            }
        }
    }
}

内容的提问来源于stack exchange，提问作者Coco