要查看其工作原理，请使用
GString对象执行a
println并同时返回agentName的变量。您可以从输出中看到，该行在任何其他管道代码之前的评估效果都很好。
agentName = "Windows"agentLabel = "${println 'Right Now the Agent Name is ' + agentName; return agentName}"pipeline { agent none stages { stage('Prep') { steps { script { agentName = "Linux" } } } stage('Checking') { steps { script { println agentLabel println agentName } } } stage('Final') { agent { label agentLabel } steps { script { println agentLabel println agentName } } } }}控制台输出（请注意，在此实例上我实际上没有节点标记为Windows，因此在找不到该节点后中止了操作）：
Started by user Admin[Pipeline] echoRight Now the Agent Name is Windows[Pipeline] stage[Pipeline] { (Prep)[Pipeline] script[Pipeline] {[Pipeline] }[Pipeline] // script[Pipeline] }[Pipeline] // stage[Pipeline] stage[Pipeline] { (Checking)[Pipeline] script[Pipeline] {[Pipeline] echoWindows[Pipeline] echoLinux[Pipeline] }[Pipeline] // script[Pipeline] }[Pipeline] // stage[Pipeline] stage[Pipeline] { (Final)[Pipeline] nodeStill waiting to schedule taskThere are no nodes with the label ‘Windows’Aborted by Admin[Pipeline] // node[Pipeline] }[Pipeline] // stage[Pipeline] End of PipelineERROR: Queue task was cancelledFinished: ABORTED请注意，该行在
Right Now the Agent Name isWindows输出中很早就出现了。这说明了为什么您的值为空。在您的脚本修改变量之前很久就对该语句进行了评估。
我可能稍后会尝试使用惰性
GString来获取变量。
agentLabel = "${-> println 'Right Now the Agent Name is ' + agentName; return agentName}"不幸的是，这会引发错误，因为它期望使用String类型。显然，它可以自行将非惰性GString强制转换为String，而不是强制性版本。因此，当我强制强制使用String时，它会在那时（也就是在管道代码实际运行之前）对变量进行求值。
agent { label agentLabel as String }您可以通过使用旧的节点分配方法来解决此问题：
agentName = "Windows"agentLabel = "${-> println 'Right Now the Agent Name is ' + agentName; return agentName}"pipeline { agent none stages { stage('Prep') { steps { script { agentName = "Linux" } } } stage('Checking') { steps { script { println agentLabel println agentName } } } stage('Final') { steps { node( agentLabel as String ) { // evaluate the node label later echo "TEST" } script { println agentLabel println agentName } } } }}您可以从此控制台输出中看到，它现在可以正确找到Linux节点并完成管道。Windows永远不会发生agentName == Windows的早期评估：
Started by user Admin[Pipeline] stage[Pipeline] { (Prep)[Pipeline] script[Pipeline] {[Pipeline] }[Pipeline] // script[Pipeline] }[Pipeline] // stage[Pipeline] stage[Pipeline] { (Checking)[Pipeline] script[Pipeline] {[Pipeline] echoRight Now the Agent Name is Linux[Pipeline] echoLinux[Pipeline] }[Pipeline] // script[Pipeline] }[Pipeline] // stage[Pipeline] stage[Pipeline] { (Final)[Pipeline] echoRight Now the Agent Name is Linux[Pipeline] nodeRunning on Slave 1 in /home/jenkinsslave/jenkins/workspace/test[Pipeline] {[Pipeline] echoTEST[Pipeline] }[Pipeline] // node[Pipeline] script[Pipeline] {[Pipeline] echoRight Now the Agent Name is Linux[Pipeline] echoLinux[Pipeline] }[Pipeline] // script[Pipeline] }[Pipeline] // stage[Pipeline] End of PipelineFinished: SUCCESS如果没有延迟
GString和类型强制，这可能会起作用，但是我没有尝试过。
