How to replace github branch inside jenkins job scm from parameter value - jenkins

Question

I have a jenkins job groovy script like below. I want the Github branch to be taken from the parameter value.
Groovy Script :
git_url = "git#github.deere.com:ABC/XYZ.git" jenkins_node = "master"
freeStyleJob('myjob') {
logRotator(numToKeep = 100)
parameters { stringParam("GIT_BRANCH", "master" , "master cert dev") }
label(jenkins_node)
scm {
git {
remote { url(git_url) }
branch($GIT_BRANCH)
extensions { }
}
}

Answer 1

You have to put $GIT_BRANCH variable into single quotes so it is not get parsed by job DSL script. Paste your script to this Job DSL playground app and you will get an exception:
javaposse.jobdsl.dsl.DslScriptException: (script, line 12) No such property: $GIT_BRANCH for class: javaposse.jobdsl.dsl.helpers.scm.GitContext
at javaposse.jobdsl.dsl.AbstractDslScriptLoader.runScriptEngine(AbstractDslScriptLoader.groovy:112)
at javaposse.jobdsl.dsl.AbstractDslScriptLoader$_runScripts_closure1.doCall(AbstractDslScriptLoader.groovy:59)
at javaposse.jobdsl.dsl.AbstractDslScriptLoader.runScripts(AbstractDslScriptLoader.groovy:46)
at javaposse.jobdsl.dsl.AbstractDslScriptLoader$runScripts$0.callCurrent(Unknown Source)
But if you add single quotes:
branch('$GIT_BRANCH')
then you will get your job XML file generated correctly:
<!-- 1. myjob -->
<project>
<actions></actions>
<description></description>
<keepDependencies>false</keepDependencies>
<properties>
<hudson.model.ParametersDefinitionProperty>
<parameterDefinitions>
<hudson.model.StringParameterDefinition>
<name>GIT_BRANCH</name>
<defaultValue>master</defaultValue>
<description>master cert dev</description>
</hudson.model.StringParameterDefinition>
</parameterDefinitions>
</hudson.model.ParametersDefinitionProperty>
</properties>
<canRoam>false</canRoam>
<disabled>false</disabled>
<blockBuildWhenDownstreamBuilding>false</blockBuildWhenDownstreamBuilding>
<blockBuildWhenUpstreamBuilding>false</blockBuildWhenUpstreamBuilding>
<triggers></triggers>
<concurrentBuild>false</concurrentBuild>
<builders></builders>
<publishers></publishers>
<buildWrappers></buildWrappers>
<logRotator>
<daysToKeep>100</daysToKeep>
<numToKeep>-1</numToKeep>
<artifactDaysToKeep>-1</artifactDaysToKeep>
<artifactNumToKeep>-1</artifactNumToKeep>
</logRotator>
<assignedNode>master</assignedNode>
<scm class='hudson.plugins.git.GitSCM'>
<userRemoteConfigs>
<hudson.plugins.git.UserRemoteConfig>
<url>git#github.deere.com:ABC/XYZ.git</url>
</hudson.plugins.git.UserRemoteConfig>
</userRemoteConfigs>
<branches>
<hudson.plugins.git.BranchSpec>
<name>$GIT_BRANCH</name>
</hudson.plugins.git.BranchSpec>
</branches>
<configVersion>2</configVersion>
<doGenerateSubmoduleConfigurations>false</doGenerateSubmoduleConfigurations>
<gitTool>Default</gitTool>
</scm>
</project>
Here is job DSL I used in the sandbox:
git_url = "git#github.deere.com:ABC/XYZ.git"
jenkins_node = "master"
freeStyleJob('myjob') {
logRotator(numToKeep = 100)
parameters {
stringParam("GIT_BRANCH", "master" , "master cert dev")
}
label(jenkins_node)
scm {
git {
remote { url(git_url) }
branch('$GIT_BRANCH')
extensions { }
}
}
}
Now when you run a job generated from this DSL it will ask you for GIT_BRANCH parameter and the value you pass will be used to set up the branch.