Jenkins groovy - How to retrieve tag from latest commit?

Question

To fetch the latest commit from branchName, we run below code:

treeMapData = git(branch: branchName, credentialsId: credential, url: "${gitLabServer}/${projectName}/${repo}.git")

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It is ensured that there is one tag per commit, as per our workflow

We want to build the code, only if the commit is tagged.

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How to retrieve the tag name for that latest commit?

Answer 1

We can fetch the tags from the repo in case Jenkins hasn't already.

git fetch --tags

We need to find a tag(s) which point to a specific commit or HEAD in our case. Thankfully there is a handy command in git which allows us to do this.

git tag --points-at HEAD

Using awk we can turn this into an output which groovy can falsify.

awk NF

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So we, first we check if the pushed branch is master

if (env.BRANCH_NAME == 'master') {

lock it down

  lock('publish master') {

execute the git tag shell script and assign it to TAG

    TAG = sh (
      returnStdout: true,
      script: 'git fetch --tags && git tag --points-at HEAD | awk NF'
    ).trim()

if a tag exists, do something!

    if (TAG) {
      stage('Deploy Prod') {
        echo "Deploying to Prod ${TAG}"
      }
    }

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Hopefully this answers your question, or at the very least will get you on the right track.

Answer 2

Just in case anyone needs this (like I did): you need to build from a tag, not from a commit. Then env.TAG_NAME becomes available and you can write code like this:

if(env.TAG_NAME) {
    ...
}