Jenkins checking change in repository before build - github

Question

I am using a monorepo for my microservices and i have a pipeline for each service.I have a webhook that notifies jenkins whenever a change is made in the repository. So the problem now is i want to check a particular folder in the repository if there is a change before some operations. Thanks

Answer 1

Solution 01 Processing the Webhook Request
When the Webhook notifies Jenkins it will send a bunch of details to Jenkins. Including the change logs. You should be receiving the below details. So as the initial step you can process the details coming from Github and determine whether the folder you are looking for is changed.
"added": [ ],
"removed": [ ],
"modified": ["test/testfile.yaml"]
You can use this as a reference.
Solution 02 without Processng the Webhook
It seems you cannot get this done with a simple pattern matching as directory name checking is not supported at the moment. But as a workaround, you can use something like the below. You can specify the directory name you want to check as folderName = "DIR_NAME"
pipeline {
agent any
stages {
stage('Cloning') {
steps {
// Get some code from a GitHub repository
git branch: 'main', url: 'https://github.com/yasassri/sample.git'
}
}
stage('Example Deploy') {
when { expression {
def changeLogSets = currentBuild.changeSets
def folderName = "testdir2"
for (int i = 0; i < changeLogSets.size(); i++) {
def entries = changeLogSets[i].items
for (int j = 0; j < entries.length; j++) {
def entry = entries[j]
def files = new ArrayList(entry.affectedFiles)
for (int k = 0; k < files.size(); k++) {
def file = files[k]
if(file.path.contains(folderName)){
return true
}
}
}
}
return false
}
}
steps {
echo 'Deploying==================='
}
}
}
}
References: https://support.cloudbees.com/hc/en-us/articles/217630098-How-to-access-Changelogs-in-a-Pipeline-Job-