using shell variables in Jenkins pipeline - jenkins

Question

I have a use case in which I have to write a shell script as a variable in Jenkins Pipeline and run the same. The short notion of my use case is as follows
pipeline{
agent any
stages{
stage('print Vars'){
steps{
script{
String script = """
export pipelineScriptVar='This is a var'
echo "${pipelineScriptVar}" """
sh script
}
}
}
}
}
When I try to run the same, I am getting the following error.
groovy.lang.MissingPropertyException: No such property: pipelineScriptVar for class: groovy.lang.Binding
at groovy.lang.Binding.getVariable(Binding.java:63)
at org.jenkinsci.plugins.scriptsecurity.sandbox.groovy.SandboxInterceptor.onGetProperty(SandboxInterceptor.java:251)
at org.kohsuke.groovy.sandbox.impl.Checker$7.call(Checker.java:353)
at org.kohsuke.groovy.sandbox.impl.Checker.checkedGetProperty(Checker.java:357)
at org.kohsuke.groovy.sandbox.impl.Checker.checkedGetProperty(Checker.java:333)
at org.kohsuke.groovy.sandbox.impl.Checker.checkedGetProperty(Checker.java:333)
at org.kohsuke.groovy.sandbox.impl.Checker.checkedGetProperty(Checker.java:333)
at com.cloudbees.groovy.cps.sandbox.SandboxInvoker.getProperty(SandboxInvoker.java:29)
at com.cloudbees.groovy.cps.impl.PropertyAccessBlock.rawGet(PropertyAccessBlock.java:20)
at WorkflowScript.run(WorkflowScript:12)
at ___cps.transform___(Native Method)
at com.cloudbees.groovy.cps.impl.PropertyishBlock$ContinuationImpl.get(PropertyishBlock.java:74)
at com.cloudbees.groovy.cps.LValueBlock$GetAdapter.receive(LValueBlock.java:30)
at com.cloudbees.groovy.cps.impl.PropertyishBlock$ContinuationImpl.fixName(PropertyishBlock.java:66)
at jdk.internal.reflect.GeneratedMethodAccessor176.invoke(Unknown Source)
at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.base/java.lang.reflect.Method.invoke(Method.java:566)
at com.cloudbees.groovy.cps.impl.ContinuationPtr$ContinuationImpl.receive(ContinuationPtr.java:72)
at com.cloudbees.groovy.cps.impl.ConstantBlock.eval(ConstantBlock.java:21)
at com.cloudbees.groovy.cps.Next.step(Next.java:83)
at com.cloudbees.groovy.cps.Continuable$1.call(Continuable.java:174)
at com.cloudbees.groovy.cps.Continuable$1.call(Continuable.java:163)
at org.codehaus.groovy.runtime.GroovyCategorySupport$ThreadCategoryInfo.use(GroovyCategorySupport.java:136)
at org.codehaus.groovy.runtime.GroovyCategorySupport.use(GroovyCategorySupport.java:275)
at com.cloudbees.groovy.cps.Continuable.run0(Continuable.java:163)
at org.jenkinsci.plugins.workflow.cps.SandboxContinuable.access$001(SandboxContinuable.java:18)
at org.jenkinsci.plugins.workflow.cps.SandboxContinuable.run0(SandboxContinuable.java:51)
at org.jenkinsci.plugins.workflow.cps.CpsThread.runNextChunk(CpsThread.java:187)
at org.jenkinsci.plugins.workflow.cps.CpsThreadGroup.run(CpsThreadGroup.java:420)
at org.jenkinsci.plugins.workflow.cps.CpsThreadGroup.access$400(CpsThreadGroup.java:95)
at org.jenkinsci.plugins.workflow.cps.CpsThreadGroup$2.call(CpsThreadGroup.java:330)
at org.jenkinsci.plugins.workflow.cps.CpsThreadGroup$2.call(CpsThreadGroup.java:294)
at org.jenkinsci.plugins.workflow.cps.CpsVmExecutorService$2.call(CpsVmExecutorService.java:67)
at java.base/java.util.concurrent.FutureTask.run(FutureTask.java:264)
at hudson.remoting.SingleLaneExecutorService$1.run(SingleLaneExecutorService.java:139)
at jenkins.util.ContextResettingExecutorService$1.run(ContextResettingExecutorService.java:28)
at jenkins.security.ImpersonatingExecutorService$1.run(ImpersonatingExecutorService.java:68)
at java.base/java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:515)
at java.base/java.util.concurrent.FutureTask.run(FutureTask.java:264)
at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128)
at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628)
at java.base/java.lang.Thread.run(Thread.java:829)
Finished: FAILURE
but when I remove the echo step and try to grep the environment variable like this.
export pipelineScriptVar='This is a var'
env | grep "pipeline"
I am getting the expected output.

Answer 1

In your case you are declaring pipelineScriptVar inside a string called script, so when you run this script variable as shell jenkins consider pipelineScriptVar as jenkins variable not a shell variable.
So you can use '\' to suppress the string notation of jenkins. Use '\' before ${pipelineScriptVar} like \${pipelineScriptVar}. Hope you find this useful

Answer 2

When you use double-quotes(") surrounding your script(or any other String variable) the string is interpolated and the variables are replaced by Jenkins. So instead of surrounding with double-quotes surround your script with single-quotes.
pipeline{
agent any
stages{
stage('print Vars'){
steps{
script{
String script = '''
export pipelineScriptVar='This is a var'
echo "${pipelineScriptVar}" '''
sh script
}
}
}
}
}
Or as Dharani mentioned you can escape the $ with a backslash. \$