Jenkins Declarative Pipeline: How to read choice from input step?

Question

I'm trying to access a variable from an input step using the declarative pipelines syntax but it seems not to be available via env or params. This is my stage definition:

stage('User Input') {     steps {         input message: 'User input required', ok: 'Release!',             parameters: [choice(name: 'RELEASE_SCOPE', choices: 'patch\nminor\nmajor', description: 'What is the release scope?')]         echo "env: ${env.RELEASE_SCOPE}"         echo "params: ${params.RELEASE_SCOPE}"     } } 

Both echo steps print null. I also tried to access the variable directly but I got the following error:

groovy.lang.MissingPropertyException: No such property: RELEASE_SCOPE for class: groovy.lang.Binding     at groovy.lang.Binding.getVariable(Binding.java:63)     at org.jenkinsci.plugins.scriptsecurity.sandbox.groovy.SandboxInterceptor.onGetProperty(SandboxInterceptor.java:224) 

What is the correct way to access this choice parameter?

Answer 1

Since you are using declarative pipelines we will need to do some tricks. Normally you save the return value from the input stage, like this

def returnValue = input message: 'Need some input', parameters: [string(defaultValue: '', description: '', name: 'Give me a value')] 

However this is not allowed directly in declarative pipeline steps. Instead, what you need to do is wrap the input step in a script step and then propagate the value into approprierte place (env seems to work good, beware that the variable is exposed to the rest of the pipeline though).

pipeline {     agent any     stages {         stage("foo") {             steps {                 script {                     env.RELEASE_SCOPE = input message: 'User input required', ok: 'Release!',                             parameters: [choice(name: 'RELEASE_SCOPE', choices: 'patch\nminor\nmajor', description: 'What is the release scope?')]                 }                 echo "${env.RELEASE_SCOPE}"             }         }     } } 

Note that if you have multiple parameters in the input step, then input will return a map and you need to use map references to get the entry that you want. From the snippet generator in Jenkins:

If just one parameter is listed, its value will become the value of the input step. If multiple parameters are listed, the return value will be a map keyed by the parameter names. If parameters are not requested, the step returns nothing if approved.