Git Variables in Jenkins Workflow plugin

Depending on the SCM plugin you are using, the checkout step may return additional information about the revision. This was resolved in JENKINS-26100. It was released in the 2.6 version of the workflow-scm-step plugin.

For example, using the Git plugin, you can do something like:

final scmVars = checkout(scm)
echo "scmVars: ${scmVars}"
echo "scmVars.GIT_COMMIT: ${scmVars.GIT_COMMIT}"
echo "scmVars.GIT_BRANCH: ${scmVars.GIT_BRANCH}"

This will vary depending on the plugin you use, so the original answer may work better for you.

---

Original Answer

With the 2.4 release of the Pipeline Nodes and Processes Plugin, you can simply do:

def gitCommit = sh(returnStdout: true, script: 'git rev-parse HEAD').trim()

This is what I'm doing, based on the example provided in the Jenkins examples repo:

node {
    git url: 'https://git.com/myproject.git'

    sh 'git rev-parse --abbrev-ref HEAD > GIT_BRANCH'
    git_branch = readFile('GIT_BRANCH').trim()
    echo git_branch

    sh 'git rev-parse HEAD > GIT_COMMIT'
    git_commit = readFile('GIT_COMMIT').trim()
    echo git_commit
}

Edit you can do this shorter via

git_commit = sh(returnStdout: true, script: "git rev-parse HEAD").trim()

Depending on the information you need, there is a very straightforward solution: get the "checkout scm" operation return: it provides GIT_BRANCH, GIT_COMMIT, GIT_PREVIOUS_COMMIT, GIT_PREVIOUS_SUCCESSFUL_COMMIT and GIT_URL.

node { 
    stage ("Checkout") {

        scmInfo = checkout scm

        /*...*/
        echo "scm : ${scmInfo}"
        echo "${scmInfo.GIT_COMMIT}"


    }
}

This will output:

...
[Pipeline] echo
    scm : [GIT_BRANCH:my-branch, GIT_COMMIT:0123456789abcdefabcdef0123456789abcdef01, GIT_PREVIOUS_COMMIT:aaaabbbcccdddeeeefffe0123456789012345678, GIT_PREVIOUS_SUCCESSFUL_COMMIT:aaaabbbcccdddeeeefffe0123456789012345678, GIT_URL:http://my.si.te/my-repository.git]
[Pipeline] echo
    0123456789abcdefabcdef0123456789abcdef01
...

More details here Jenkins Pipeline SCM Steps