How to get pull request id from Jenkins Pipeline - github

Question

I'm trying to analyse my source code with Sonar using Jenkins pipelines. To ask Sonar to notify Github with the results I need to specify the Pull Request ID.
How can I get this Pull Request ID from Jenkins Pipelines?
We are using GitHub Organization Folder Plugin to build pull requests, not GitHub pull request builder plugin. That's why $ghprbPullId is not working for me. Any ideas how to get the pull request id in a different way?

Answer 1

Jenkins exposes a global variable named CHANGE_ID:
For a multibranch project corresponding to some kind of
change request, this will be set to the change ID, such as a pull
request number.
This variable is only populated for pull request builds, so you have to disable branch builds and enable PR builds in your pipeline's configuration for branch sources:
My pipeline step then looks like this:
def PULL_REQUEST = env.CHANGE_ID
stage('Analysis') {
withCredentials([[$class: 'StringBinding', credentialsId: '***', variable: 'GITHUB_ACCESS_TOKEN']]) {
withSonarQubeEnv('Sonar') {
withMaven(maven: 'M3') {
sh "mvn org.sonarsource.scanner.maven:sonar-maven-plugin:3.2:sonar " +
"-Dsonar.analysis.mode=preview " +
"-Dsonar.github.pullRequest=${PULL_REQUEST} " +
"-Dsonar.github.oauth=${GITHUB_ACCESS_TOKEN}"
}
}
}
}

Answer 2

You get the PR number through for example env.BRANCH_NAME.
if (env.BRANCH_NAME.startsWith('PR-')) {
def prNum = env.BRANCH_NAME.replace(/^PR-/, '')
...
}

Answer 3

In the case that Thomas' answer doesn't work or apply to you, you may also (possibly) use the branch name to get the Pull Request number by querying the Github REST API. All you need is an API token and the branch name, lookup the pull requests in order of date updated DESC, and find the first PR that matches your branch name. That will have the Pull Request number.
This only works if you have a unique branch name for each pull request (such as a JIRA issue ticket number).