SCM polling with includedRegions in Jenkins pipeline job - jenkins

Question

I am using GitLab. Given multiple directories, e.g. folder1, folder2, folder3. I would like the job run only if there is any changes under folder1 only. Does anyone able to get includedRegions to work in Jenkins pipeline job.
checkout(
[
$class: 'GitSCM',
branches: [[name: '*/master']],
doGenerateSubmoduleConfigurations: false,
extensions: [[$class: 'PathRestriction', excludedRegions: '', includedRegions: 'folder1/.*']],
submoduleCfg: [],
userRemoteConfigs: [[credentialsId: 'user', url: 'ssh://something/experiment.git']]
]
)

Answer 1

If you use a pipeline the checkout step performs after the build was launched.
The only way to manage this is to check the changeset with the groovy and skip the build if there were no changes at the included directory.

Answer 2

I managed to get it working. Since the checkout will be used across projects in our Jenkins, I wrote shared libraries to make it handy to use.
Example: strToSparseCheckout.groovy
#!/usr/bin/env groovy
import hudson.plugins.git.extensions.impl.SparseCheckoutPath
def call(paths) {
def list = paths.split('\n')
def sparsePaths = []
def isDefaultAdded = false
list.each {
def path = it - '/.*'
def sparsePath = new SparseCheckoutPath(path)
sparsePaths.push(sparsePath)
}
return sparsePaths
}
Example: sparseCheckout.groovy
#!/usr/bin/env groovy
def call(Map namedargs) {
checkout(
[
$class: 'GitSCM',
branches: [[name: "${namedargs.branch}"]],
extensions: [
[$class: 'LocalBranch', localBranch: '**'],
[$class: 'RelativeTargetDirectory', relativeTargetDir: "${namedargs.target_dir}"],
[$class: 'SparseCheckoutPaths', sparseCheckoutPaths: strToSparseCheckout("${namedargs.included_regions}")],
[$class: 'PathRestriction', excludedRegions: """${namedargs.excluded_regions}""", includedRegions: """${namedargs.included_regions}"""]
],
userRemoteConfigs: [[credentialsId: 'user', url: "${namedargs.url}"]]
]
)
}
In the pipeline, we can call the sparseCheckout shared library.
pipeline {
stage('Checkout') {
sparseCheckout(
[
url: 'ssh://path.to.git/something.git',
branch: 'refs/heads/master',
target_dir: 'something',
excluded_regions: "${params.excluded_regions}",
included_regions: "${params.included_regions}"
]
)
}
}