groovy.lang.MissingPropertyException while stopping a container - docker

Question

I am trying to use hadolint for my Dockerfile and then stop and remove the container right after the linting is done.
The provided code was working just fine but it was not showing any errors when there are linting issues as the container was by default running in detached mode. After adding --detach=false option, I can see the messages when there are linting issues. However, now error arises when it tries to execute the always post condition. Any help or suggestion will be greatly appreciated. Thank you.
stage('Lint') {
steps {
script {
hado = docker.image('hadolint/hadolint').run('--rm -i --detach=false', '< Dockerfile')
}
}
post {
always {
script {
hado.stop()
}
}
}
}
[Pipeline] stage
[Pipeline] { (Lint)
[Pipeline] script
[Pipeline] {
[Pipeline] sh
+ docker run -d -i --detach=false hadolint/hadolint
[Pipeline] dockerFingerprintRun
[Pipeline] }
[Pipeline] // script
Post stage
[Pipeline] script
[Pipeline] {
[Pipeline] }
[Pipeline] // script
Error when executing always post condition:
groovy.lang.MissingPropertyException: No such property: hado for class: groovy.lang.Binding
at groovy.lang.Binding.getVariable(Binding.java:63)
at org.jenkinsci.plugins.scriptsecurity.sandbox.groovy.SandboxInterceptor.onGetProperty(SandboxInterceptor.java:270)
at org.kohsuke.groovy.sandbox.impl.Checker$6.call(Checker.java:289)
at org.kohsuke.groovy.sandbox.impl.Checker.checkedGetProperty(Checker.java:293)
at org.kohsuke.groovy.sandbox.impl.Checker.checkedGetProperty(Checker.java:269)
at org.kohsuke.groovy.sandbox.impl.Checker.checkedGetProperty(Checker.java:269)
at org.kohsuke.groovy.sandbox.impl.Checker.checkedGetProperty(Checker.java:269)
at com.cloudbees.groovy.cps.sandbox.SandboxInvoker.getProperty(SandboxInvoker.java:29)
at com.cloudbees.groovy.cps.impl.PropertyAccessBlock.rawGet(PropertyAccessBlock.java:20)
at WorkflowScript.run(WorkflowScript:29)
at ___cps.transform___(Native Method)
at com.cloudbees.groovy.cps.impl.PropertyishBlock$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 sun.reflect.GeneratedMethodAccessor365.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
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:129)
at org.codehaus.groovy.runtime.GroovyCategorySupport.use(GroovyCategorySupport.java:268)
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:186)
at org.jenkinsci.plugins.workflow.cps.CpsThreadGroup.run(CpsThreadGroup.java:370)
at org.jenkinsci.plugins.workflow.cps.CpsThreadGroup.access$200(CpsThreadGroup.java:93)
at org.jenkinsci.plugins.workflow.cps.CpsThreadGroup$2.call(CpsThreadGroup.java:282)
at org.jenkinsci.plugins.workflow.cps.CpsThreadGroup$2.call(CpsThreadGroup.java:270)
at org.jenkinsci.plugins.workflow.cps.CpsVmExecutorService$2.call(CpsVmExecutorService.java:66)
at java.util.concurrent.FutureTask.run(FutureTask.java:266)
at hudson.remoting.SingleLaneExecutorService$1.run(SingleLaneExecutorService.java:131)
at jenkins.util.ContextResettingExecutorService$1.run(ContextResettingExecutorService.java:28)
at jenkins.security.ImpersonatingExecutorService$1.run(ImpersonatingExecutorService.java:59)
at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
at java.util.concurrent.FutureTask.run(FutureTask.java:266)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
at java.lang.Thread.run(Thread.java:748)
[Pipeline] }
[Pipeline] // stage

Answer 1

The field hado has a local scope. Define it globally and you could use it in post actions.
def hado
pipeline {
stages {
stage('Lint') {
steps {
hado = ...
}
}
}
post {
always {
hado.stop()
}
}
}