Jenkins Workflow Checkout Accessing BRANCH_NAME and GIT_COMMIT

Question

I cannot seem to extract $GIT_COMMIT and $BRANCH_NAME from a Jenkins Workflow Checkout step.

I would like to be able to send this information through to my Gradle scripts in order to pass it onto external sources such as Static analysis etc.

Currently I try to run this:

checkout([$class: 'GitSCM', branches: [[name: '*/master']], userRemoteConfigs: [[credentialsId: '2b74a351-67d5-4d00-abd3-49842a984201', url: 'ssh://git@corporate.com:repo.git']]])

And I would like to achieve the following or something similar:

// Specified variables that can be reused
def branch = ${BRANCH_NAME}
def commit = ${GIT_COMMIT}

Or maybe this would work too:

print "BRANCH: ${BRANCH_NAME}, COMMIT: ${GIT_COMMIT}"
// or the following
print "BRANCH: ${env.BRANCH_NAME}, COMMIT: ${env.GIT_COMMIT}"

I did find the following issue which seems to be resolved but it doesn't work in version 1.15:

https://issues.jenkins-ci.org/browse/JENKINS-30252

Anyone have any ideas how to workaround this or if there's a variable I cannot find?

score 43 · Answer 1 · answered Mar 31 '16 at 11:29

First of all,

def branch = ${BRANCH_NAME}

is not valid Groovy, or at least not doing what you think. Perhaps you meant

def branch = "${BRANCH_NAME}"

which would just be a silly way of writing

def branch = BRANCH_NAME

Anyway environment variables are not currently accessible directly as Groovy variables in Pipeline (there is a proposal to allow it); you need to use the env global variable:

def branch = env.BRANCH_NAME

From within an external process, such as a sh step, it is an actual environment variable, so

sh 'echo $BRANCH_NAME'

works (note that ' means Groovy is not interpolating the variable).

Now, JENKINS-30252 was referring to multibranch projects. If you created a standalone Pipeline job, this variable will not be set.

Anyway in your case your checkout step is always checking out the master branch. If you actually have a multibranch project, then your Jenkinsfile should be using

checkout scm

which will check out a commit on the correct branch (always matching the revision of Jenkinsfile itself).

As to the commit hash, pending JENKINS-26100 this is not available automatically, but you can use something like

sh 'git rev-parse HEAD > commit'
def commit = readFile('commit').trim()

to access it.

Alright, so this helps me understand the problem better. There's a few things I don't know about Groovy as mentioned above but this helps me understand the differences of quotes as well. Interesting, I will try this out! — Oldek, Apr 01 '16 at 09:43
As to the last paragraph, see the [currently proposed syntax](https://github.com/abayer/workflow-scm-step-plugin/blob/39a28c8611c2c06e14d9e60b4a06366c57bfec18/src/main/resources/org/jenkinsci/plugins/workflow/steps/scm/GenericSCMStep/help.html). — Jesse Glick, May 04 '17 at 12:25
"environment variables are not currently accessible directly as Groovy variables" Do you have any supporting references for this from Jenkins source? — Judy007, Jun 28 '17 at 18:36
@JoeyStallmeyer He also states "you need to use the env global variable". So, the environment variable `BRANCH_NAME` can be accessed with this: `env.BRANCH_NAME` (as stated in the answer). — alexbt, Jul 11 '17 at 21:04

score 23 · Answer 2 · answered Aug 23 '17 at 16:43

I have two Jenkins instances.

In both instances, GIT_COMMIT and BRANCH_NAME environment variables are not defined.

When I try to get them from the return value of checkout() call, each instance behaves differently.

Jenkins Instance 1

Jenkins version: 2.46.1

"Pipeline: SCM Step" plugin version: 2.5

Trying to access the environment variable as explained in the checkout documentation fails.

def scmVars = checkout([$class: 'GitSCM', branches: [[name: '*/master']], 
    userRemoteConfigs: [[credentialsId: '2b74a351-67d5-4d00-abd3-
    49842a984201', url: 'ssh://git@corporate.com:repo.git']]])
def commitHash = scmVars.GIT_COMMIT

scmVars returns NULL, and accessing scmVars.GIT_BRANCH fails with exception java.lang.NullPointerException: Cannot get property 'GIT_BRANCH' on null object.

So I had to do the following in order to get the branch:

sh 'git name-rev --name-only HEAD > GIT_BRANCH'
sh 'cat GIT_BRANCH'
git_branch = readFile('GIT_BRANCH').trim()
env.GIT_BRANCH = git_branch

Jenkins Instance 2

Jenkins version: 2.60.2

"Pipeline: SCM Step" plugin version: 2.6

In this instance, I could do the following with success:

def scmVars = checkout([$class: 'GitSCM', branches: [[name: '*/master']], 
    userRemoteConfigs: [[credentialsId: '2b74a351-67d5-4d00-abd3-
    49842a984201', url: 'ssh://git@corporate.com:repo.git']]])
env.GIT_COMMIT = scmVars.GIT_COMMIT
env.GIT_BRANCH = scmVars.GIT_BRANCH

So please check which approach works for your Jenkins instance and use it.

Thank you so much for your detailed explanation on failure regarding versions. I can confirm that for Jenkins Instance 2 with "Pipeline: SCM Step" plugin version: 2.5 also fails on your second explanation. On version 2.73.3 of Jenkins, so it's definitely an error on the plugin on versions below 2.6, updating it solved this — Ilhicas, Feb 28 '18 at 16:26
@Antony Thanks a lot for this answer you have almost saved my job!!. The second approach worked for me!. :-) — Hussain K, Aug 04 '20 at 04:10

score 1 · Answer 3 · edited Feb 19 '18 at 12:32

1

If you want to access the BRANCH_NAME from Jenkins environment variable as a shell script, use the below snippet.

sh 'echo Branch Name: $BRANCH_NAME'

The response should be as below:

Branch Name: the_checkedout_branch

edited Feb 19 '18 at 12:32

Adeel

2,901
7
24
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answered Feb 19 '18 at 11:20

Eazhilan Nagarajan

11
2

Jenkins Workflow Checkout Accessing BRANCH_NAME and GIT_COMMIT

3 Answers3

Jenkins Instance 1

Jenkins Instance 2

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