[git] Get git branch name in Jenkins Pipeline/Jenkinsfile

I've create a jenkins pipeline and it is pulling the pipeline script from scm.
I set the branch specifier to 'all', so it builds on any change to any branch.

How do I access the branch name causing this build from the Jenkinsfile?

Everything I have tried echos out null except

sh(returnStdout: true, script: 'git rev-parse --abbrev-ref HEAD').trim()

which is always master.

This is for simple Pipeline type - not multibranch. Using Jenkins 2.150.1

environment { FULL_PATH_BRANCH = "${sh(script:'git name-rev --name-only HEAD', returnStdout: true)}" GIT_BRANCH = FULL_PATH_BRANCH.substring(FULL_PATH_BRANCH.lastIndexOf('/') + 1, FULL_PATH_BRANCH.length()) }

then use it env.GIT_BRANCH

For me this worked: (using Jenkins 2.150, using simple Pipeline type - not multibranch, my branch specifier: '**')

echo 'Pulling... ' + env.GIT_BRANCH

Output:

Pulling... origin/myBranch

where myBranch is the name of the feature branch

A colleague told me to use scm.branches[0].name and it worked. I wrapped it to a function in my Jenkinsfile:

def getGitBranchName() {
    return scm.branches[0].name
}

Use multibranch pipeline job type, not the plain pipeline job type. The multibranch pipeline jobs do posess the environment variable env.BRANCH_NAME which describes the branch.

In my script..

stage('Build') {
    node {
        echo 'Pulling...' + env.BRANCH_NAME
        checkout scm
        
    }
}

Yields...

Pulling...master

For pipeline:

pipeline {
  environment {
     BRANCH_NAME = "${GIT_BRANCH.split("/")[1]}"
  }
}

FWIW the only thing that worked for me in PR builds was ${CHANGE_BRANCH}

(may not work on master, haven't seen that yet)

Switching to a multibranch pipeline allowed me to access the branch name. A regular pipeline was not advised.

Just getting the name from scm.branches is not enough if you've used a build parameter as a branch specifier, e.g. ${BRANCH}. You need to expand that string into a real name:

scm.branches.first().getExpandedName(env.getEnvironment())

Note that getEnvironment() must be an explicit getter otherwise env will look up for an environment variable called environment.

Don't forget that you need to approve those methods to make them accessible from the sandbox.